Fructose consumption induces molecular adaptations involving thyroid function and thyroid-related genes in brown adipose tissue in rats

The increasing incidence of metabolic diseases is in part due to the high fructose consumption, a carbohydrate vastly used in industry, with a potent lipogenic capacity. Thyroid hormones (TH) are essential for metabolism regulation and are associated with changes in body weight, energy expenditure, insulin sensitivity, and dyslipidemia. This study aimed to investigate the influence of fructose intake on thyroid function and thyroid-related genes. Male Wistar rats were divided into Control (CT, n=8) and Fructose (FT - 10% in drinking water, n=8) groups for three weeks. The FT group showed higher glycemia and serum triacylglycerol, indicating metabolic disturbances, and increased thyroid mass, accompanied by higher expression of Srebf1c and Lpl, suggesting increased lipid synthesis. The FT group also presented higher expression of Tpo and Dio1 in the thyroid, suggesting activation of the thyroid gland, but with no alterations in serum TH concentrations. Brown adipose tissue (BAT) of the FT group exhibited higher expression of Dio2, Thra, and Thrb, indicating increased T3 intra-tissue bioavailability and signaling. These responses were accompanied by increased BAT mass and higher expression of Adrb3, Pparg, Srebf1c, Fasn, Ppara, and Ucp1, suggesting increased BAT adrenergic sensitivity, lipid synthesis, oxidation, and thermogenesis. Therefore, short-term fructose consumption induced thyroid molecular alterations and increased BAT expression of thyroid hormone-related signaling genes that potentially contributed to higher BAT activity.

Cosmarium bromelicola sp. nov. (Desmidiaceae, Zygnematophyceae), a new desmid species from Northeast Brazil / Cosmarium bromelicola sp. nov. (Desmidiaceae, Zygnematophyceae), uma nova espécie de desmídia do nordeste do Brazil

Abstract Cosmarium bromelicola sp. nov. is a new desmid species described from samplings carried out in bromeliad tanks (phytotelmata) from an area of rocky outcrops at Serra da Jiboia, Bahia State, Northeast Brazil. Presence of subtrapeziform cells with a deep depression at the apical region and twisted X-shaped cell in side view are the diagnostic features for the species. Relationships with the morphologically closest taxa are discussed.

Resumo Cosmarium bromelicola sp. nov. é uma nova espécie de desmídia descrita a partir de amostragens realizadas em tanques de bromélias (fitotelmata) de uma área de afloramentos rochosos na Serra da Jiboia, Bahia, nordeste do Brasil. A presença de células trapeziformes com uma depressão profunda na região apical e célula em forma de X em vista lateral são as características diagnósticas da espécie. Relações com os táxons morfologicamente próximos são discutidas.

Cosmarium bromelicola sp. nov. (Desmidiaceae, Zygnematophyceae), a new desmid species from Northeast Brazil

Abstract Cosmarium bromelicola sp. nov. is a new desmid species described from samplings carried out in bromeliad tanks (phytotelmata) from an area of rocky outcrops at Serra da Jiboia, Bahia State, Northeast Brazil. Presence of subtrapeziform cells with a deep depression at the apical region and twisted X-shaped cell in side view are the diagnostic features for the species. Relationships with the morphologically closest taxa are discussed.

Resumo Cosmarium bromelicola sp. nov. é uma nova espécie de desmídia descrita a partir de amostragens realizadas em tanques de bromélias (fitotelmata) de uma área de afloramentos rochosos na Serra da Jiboia, Bahia, nordeste do Brasil. A presença de células trapeziformes com uma depressão profunda na região apical e célula em forma de X em vista lateral são as características diagnósticas da espécie. Relações com os táxons morfologicamente próximos são discutidas.

Morphology and vascularization of the corpus luteum of peccaries (Pecari tajacu, Linnaeus, 1758) throughout the estrous cycle / Morfologia e vascularização do corpo lúteo de catetos (Pecari tajacu, Linnaeus, 1758) ao longo do ciclo estral

The current paper characterizes the changes in morphology and vascularization of the corpus luteum of collared peccaries during the estrous cycle and correlates progesterone synthesis (P4). Twenty females were subjected to a treatment for estrus synchronization; an ear implant containing 1.5 mg of norgestomet was implanted on D0, whereas on D9 the peccaries received an IM injection of eCG 200UI and 50g of PGF2a. The animals were divided into four groups (G1, G2, G3 and G4) and euthanized on post-ovulation days 3, 12, 18 and 22. The ovaries were collected and the corpora lutea were measured and processed for histological and vascular density (Dv). Blood was collected for dosage of P4 serum. The morphology of the ovaries, the corpora lutea and P4 varied significantly during the estrous cycle (P<0.001). There was a significant co-relationship between weight and length of the ovaries and CL (r = 0.66, r = 0.52, P<0.05, respectively) and between weight, length and width of the CL and P4 (r = 0.51, r = 0.54 and r = 0.68, P<0.05, respectively). The luteal Dv was highly influenced by the estrous cycle phase (P<0.0001). The P4 and luteal Dv concentrations were higher in G2 and evidenced maximum secretory activity, with a highly significant correlation (P<0.0001). Assessed lutein parameters may estimate the phase of the estrous cycle in peccaries and the functional activity of the corpus luteum.

Objetivou-se caracterizar as variações na morfologia e vascularização do corpo lúteo (CL) de catetos durante ciclo estral (CE) e correlacioná-las com a concentração de progesterona (P4). Vinte fêmeas de cateto foram submetidas a tratamento de sincronização do estro; no D0 receberam implante auricular contendo 1,5mg de norgestomet, no D9 injeção via IM de 200UI de eCG e 50µg de PGF2α. Os animais foram divididos em quatro grupos (G1, G2, G3 e G4) e eutanasiados nos dias três, 12, 18 e 22 pós-ovulação. Os ovários foram coletados e os CL foram mensurados e processados para avaliação histológica e da densidade vascular (Dv). O sangue foi coletado para dosagem da P4 sérica. A morfologia dos ovários, CL e a concentração de P4 variaram significativamente durante o CE (P<0,001). Houve correlação significativa entre peso e comprimento dos ovários e CL (r = 0,66, r = 0,52, P<0,05, respectivamente) e entre peso, comprimento e largura do CL e a concentração de P4 (r=0,51, r=0,54 e r=0,68; P<0,05, respectivamente). A Dv do CL se mostrou muito influenciada pela fase do CE (P<0,001) e apresentou alta correlação significativa (P< 0,001). No G2 os maiores valores de P4 e Dv confirmaram máxima atividade secretória do CL nesse estádio. Os parâmetros luteínicos avaliados podem ser usados para estimar a fase do ciclo estral em catetos e a atividade funcional do CL.

Efeito da temperatura de descongelação na integridade de espermatozoides criopreservados de cães / The effect of the thawing temperature on the integrity of canine cryopreserved sperm

Avaliou-se a influência da temperatura de descongelação na integridade de espermatozoides criopreservados de cães. Foram utilizados reprodutores das raças Basset Hound (n=3) e Rottweiler (n=3), submetidos a colheitas de sêmen por manipulação peniana. As amostras de sêmen foram descongeladas a 37ºC/1min (G1) ou 70ºC/6s (G2) e avaliadas quanto à motilidade progressiva, vigor e integridade do acrossoma após 0, 30 e 60 minutos de incubação (37ºC), e ultraestrutura espermática imediatamente após a descongelação. Em todos os tempos de incubação, a motilidade progressiva dos espermatozoides descongelados a 70ºC por 6s (74,6%) foi mais alta (P<0,05) que a dos descongelados a 37ºC por 1min (64,6%). O vigor espermático não diferiu (P>0,05) entre os grupos, e o porcentual de gametas com acrossomas íntegros foi maior (P<0,05) nos espermatozoides do G1 do que no G2. Lesões ultraestruturais foram identificadas nos espermatozoides descongelados de ambos os grupos, em maior quantidade nos gametas do G2. Conclui-se que amostras congeladas de sêmen de cães devam ser descongeladas a 37ºC por 1min.

Aiming to evaluate the influence of the thawing temperature on the viability of canine cryopreserved sperm, Basset Hound (n=3) and Rottweiler (n=3) dogs were used, submitted to semen collected through manual manipulation. Semen samples were thawed at 37ºC during 1min (G1) or at 70ºC during 6s (G2), and evaluated for progressive motility, vigor and acrosome integrity, after 0, 30 e 60 minutes of incubation (37ºC), and sperm ultrastructure immediately after thawing. In all incubation times, the average of progressive motility was higher (P<0.05) in samples from G2 Group (74.6%) than from G1 (64.6%). Sperm vigor had no difference (P>0.05) between groups, and the percentage of gametes with intact acrosome was higher (P<0.05) on sperm cells from G1 than from G2. Ultrastructural changes were identified on dog sperm from both groups, and were observed in higher quantity in gametes from G2 Group. It can be concluded that samples of frozen dog sperm must be thawed at 37°C for 1min.

Impacto del edentulismo en la calidad de vida de individuos brasileños / Impact of the edentulism in the quality

Estimar la prevalencia del edentulismo total versus parcial y el impacto que esta condición produce en la calidad de vida. Método: La muestra fue compuesta por 182 pacientes, de ambos sexos, con edad a partir de 18 años, que vivían en la ciudad de Recife, inscritos para tratamiento en la Facultad de Odontología de la Universidad Federal de Pernambuco - UFPE. Esta investigación se realizó entre julio y septiembre de 2010. El edentulismo fue identificado a través del examen de inspección clínica y el impacto por medio del OHIP-14, el cual se compone por cinco dimensiones obtenidas después de la aplicación de un cuestionario estructurado. En la muestra analizada se verificó que 88,1% eran desdentados parciales; el grupo etario con mayor porcentaje fue de 31 a 50 años; 70,8% pertenecían al sexo femenino; 48,0% eran casados; 45,0% tenían el segundo grado completo; y 59,9% notificaron ingreso mensual superior a un salario mínimo. Resultados: En relación al impacto en la calidad de vida en las dimensiones mensuradas por el OHIP-14, los mayores porcentajes relatados por los individuos fueron: 67,8% dolor físico; 56,9% incómodo psicológico; y 61,9% limitación psicológica. Conclusión: En la presente pesquisa, el OHIP-14 mostró que los mayores problemas relatados por los individuos que perdieron sus dientes fueron de naturaleza funcional y social, como por ejemplo, incómodo para comer y el sentimiento de vergüenza, causando fuerte impacto en la calidad de vida, y aunque la prevalencia haya sido mayor para el edentulismo parcial, los impactos fueron mayores para los desdentados totales

Recém-nascido pequeno para a idade gestacional: repercussão nas habilidades motoras finas / Small-for-gestational-age newborn infant: repercussion on fine motor skills

OBJETIVO: Comparar as habilidades motoras finas de lactentes nascidos a termo pequenos para a idade gestacional (PIG) com as habilidades dos nascidos adequados para a idade gestacional (AIG) no terceiro mês de vida. MÉTODOS: Realizou-se um estudo observacional de corte transversal. Avaliaram-se 67 lactentes (21 PIG e 46 AIG) no terceiro mês de vida. Portadores de síndromes genéticas, malformações congênitas, infecções congênitas e aqueles que necessitaram de unidade de terapia intensiva neonatal foram excluídos. As Escalas Bayley II de Desenvolvimento Infantil foram utilizadas, com ênfase nos itens que avaliam as habilidades motoras finas. RESULTADOS: Não se observaram diferenças entre os grupos na escala motora (p=0,21) e mental (p=0,45) no terceiro mês de vida. No item "Alcança o Aro Suspenso", houve diferença significativa (teste Exato de Fisher; p=0,02), demonstrando maior frequência de execução para o grupo PIG no terceiro mês de vida. CONCLUSÕES: Supõe-se que a diferença encontrada no item "Alcança o Aro Suspenso" possa ser atribuída à grande ocorrência de movimentos dos braços observada no grupo PIG e não a uma condição melhor de desenvolvimento desse grupo.

OBJECTIVE: To compare the fine motor skills of full-term small-for-gestational-age (SGA) and appropriate-for-gestational-age (AGA) infants in the third month of life. METHODS: This observational cross-sectional study enrolled 67 infants (21 SGA and 46 AGA) in the third month of life. Infants presenting genetic syndromes, congenital malformations, congenital infections and those who needed neonatal intensive care were excluded. The Bayley Scales of Infant Development-II were used, with emphasis on items that evaluate the fine motor skills. RESULTS: No differences were observed between groups for motor (p=0.21) and mental (p=0.45) scales in the third month. There was a significant difference between the groups on the item "Reaches for Suspended Ring" (Fisher's exact test; p-value=0.02): a higher percentage of SGA infants accomplished this item in the third month of life. CONCLUSIONS: We hypothesize that the difference found in the item "Reaches for Suspended Ring" could be attributed to an increased frequency of arm movements observed in SGA infants and not to a better neurodevelopment of this group.

OBJETIVO: Comparar las habilidades motoras finas de lactantes nacidos a término pequeños para la edad gestacional (PEG) con adecuados para la edad gestacional (AEG) en el 3er mes de vida. MÉTODOS: Se realizó un estudio observacional de corte transversal. Se evaluaron a 67 lactantes (21 PEG y 46 AEG) en el 3er mes de vida. Síndromes genéticos, malformaciones congénitas, infecciones congénitas y aquellos que necesitaron de unidad de terapia intensiva neonatal fueron excluidos. Las Escalas Bayley II y de Desarrollo Infantil fueron utilizadas, con énfasis en los ítems que evalúan las habilidades motoras finas. RESULTADOS: No se observaron diferencias entre los grupos en la escala motora (p=0,21) y mental (p=0,45) en el 3er mes de vida. En el ítem "alcanza aro suspendido" hubo diferencia significativa (p=0,02; prueba Exacta de Fisher), demostrando mayor frecuencia de ejecución para el grupo PEG en el 3er mes de vida. CONCLUSIONES: Se supone que la diferencia encontrada en el ítem "alcanza el aro suspendido" pueda ser atribuida a la gran ocurrencia de movimientos de los brazos observada en el grupo PEG y no a una condición mejor de desarrollo en este grupo.

Fator de crescimento fibroblástico básico e seus receptores em relação à atividade proliferativa na placenta bubalina em diferentes fases da gestação / Basic fibloblast growth factor and its receptors in relation to proliferative activity in the buffalo placenta during gestation

Estudou-se a distribuição espaço-temporal do fator de crescimento fibroblástico básico (bFGF), do receptor 1 do fator de crescimento fibroblástico (FGFR1) e do receptor 2 do fator de crescimento fibroblástico (FGFR2) na placenta bubalina, correlacionando-a à proliferação celular. Para a detecção do bFGF, FGFR1, FGFR2 e antígeno Ki-67, colheram-se 12 placentas de búfalas nos terços inicial, médio e final da gestação, em abatedouros, e realizaram-se testes de imunoistoquímica. Detectou-se e avaliou-se a expressão do bFGF, do FGFR1, do FGFR2 e do antígeno Ki-67 ao longo da gestação. No compartimento fetal da placenta, observaram-se correlações positivas entre a expressão do bFGF e Ki-67, entre FGFR1 e Ki-67 e entre FGFR2 com Ki-67 (r=0,313, 0,358 e 0,384, respectivamente). No epitélio e estroma maternos observaram-se altas correlações entre FGFR1 e Ki-67 (r=0,739 e r=0,511, respectivamente). Os resultados sugerem envolvimento do bFGF, FGFR1 e FGFR2 na proliferação do trofoblasto enquanto no compartimento materno da placenta bubalina apenas o FGFR1 atuaria como modulador dessa atividade.

The space-temporal expression of basic fibroblast growth factor (bFGF), fibroblast growth factor receptor 1 (FGFR1) and fibroblast growth factor receptor 2 (FGFR2) in buffalo placenta and correlation to proliferative activity was studied. For the localization of bFGF, FGFR1, FGFR2 and Ki-67, 12 buffalo placentas from initial, middle and final gestational thirds were collected and immunohistochemistry tests were performed. Expression of bFGF and its receptors was detected and analyzed from the initial third until the end of gestation. In the fetal compartment, positive correlations were observed between the expression of bFGF and Ki-67, FGFR1 and Ki-67, besides FGFR2 and Ki-67 (r=0.313, 0.358 and 0.384, respectively). High correlations were found between FGFR1 and Ki-67 in maternal epithelium and stroma (r=0.789 and r=0.511, respectively). The results suggest that bFGF, FGFR1 and FGFR2 may be involved in the modulation of trophoblast proliferation, whereas maternal compartment proliferation in the buffalo placenta would only be modulated by FGFR1.

Diversidade de espécies dos gêneros de Crematogaster, Gnamptogenys e Pachycondyla (Hymenoptera: Formicidae) e complementaridade dos métodos de coleta durante a estação seca numa estação ecológica no estado do Pará, Brasil / Diversity of species of the genera Crematogaster,Gnamptogenys and Pachycondyla, (Hymenoptera: Formicidae) and complementarity of sampling methods during the dry season in an ecological station in the Brazilian state of Pará

As formigas são muito usadas em programas de inventários e monitoramentos, resultando em grande quantidade de material coletado com vários métodos, limitações financeiras e na falta de taxonomos para vários táxons. Para contribuir na elaboração de protocolos alternativos, analisamos a complementaridade de dois métodos de amostragem na detecção da riqueza de espécies. Em seis parcelas de 1 km² distribuídas em 33.000 ha de floresta primária, investigamos a diversidade e a freqüência das espécies de Crematogaster,Gnamptogenys e Pachycondyla, como parte do protocolo de formigas de serapilheira do Projeto TEAM. Em cada parcela, quatro transectos de 100 m foram instalados. Dez sub-amostras foram efetuadas por transecto, usando extrator de Winkler e armadilha de fosso. Registramos 36 espécies, sendo 15 novos registros para o Pará e 29 para a área de estudo. Dezessete espécies foram comuns aos dois métodos, onze foram capturadas com armadilhas de fosso e oito com Winkler. As proporções de espécies representadas por um indivíduo ("singletons") foram altas para ambos os métodos (> 0,4). Dezenove espécies foram coletadas por apenas um método e três foram representadas por apenas um indivíduo em cada método. A análise de ordenação (escalonamento multidimensional semi-híbrido) revelou diferenças na estrutura das comunidades de formigas obtidas pelos dois métodos de amostragem. Houve um efeito de complementaridade entre os dois métodos para a obtenção de um levantamento mais completo da riqueza de espécies, significando que ambos devem ser usados no protocolo. Outros recursos, como a rarefação e/ou diluição das amostras são recursos a serem avaliados em futuras investigações.

Ants are largely used for monitoring and inventory programs, resulting in great amounts of material sampled with several methodologies, financial limitations and lack of experts to do the taxonomy of many taxa. To contribute for the elaboration of alternative protocols, we analyzed the complementarity of two sampling methods in the detection of species richness. In 6 plots of 1 km² distributed in an area of 33,000 ha of continuous primary forest, in the Brazilian state of Pará, the diversity and the frequency of species of genera Crematogaster,Gnamptogenys and Pachycondyla were investigated, as part of the "Ant methodology Protocol" of the Project TEAM. Using the Winkler extractor and pitfall traps, 10 sub-samples were collected per transect. In each plot, 4 transects of 100 m were installed. We registered 36 species, and 15 are new records for the state, and 29 for the study site. Seventeen species were common to both sampling methods, 11 were captured with pitfall and 8 with Winkler. The proportions of singletons were high for both methods (>0,4). Nineteen species were captured by only one method and three were represented by only one individual in both methods. Ordination analysis (SSH, Semi-Strong Hybrid Multi-Dimensional Scaling) indicated differences in community structure between both sampling methods. There was a complementarity's effect between these two methods in order to obtain a more complete inventory of the species richness, indicating that both must be used in the protocol. Other resources like rarefaction and/or sample dilution must be evaluated in future investigations.

Avaliação histomorfométrica do parênquima testicular de ratos adultos tratados com diferentes doses de ivermectina / Histomorphometric evaluation of testicular parenchyma of adult rats treated with different dosages of ivermectin

Avaliou-se o efeito da ivermectina sobre o parênquima testicular através da produção espermática diária e da eficiência da espermatogênese em ratos Wistar adultos tratados com diferentes dosagens (200, 400 e 600æg/kg). Pela avaliação histomorfométrica, o parênquima testicular e o processo espermatogênico dos ratos Wistar não sofreram qualquer efeito deletério da aplicação de ivermectina, o que foi confirmado pela manutenção da produção espermática diária por testículo, pelo rendimento intrínseco da espermatogênese (PED/g/t) e pela manutenção da estrutura do parênquima testicular. Com base nos resultados quantitativos e qualitativos da espermatogênese, é possível concluir que a ivermectina não tem efeito tóxico-degenerativo sobre o parênquima testicular de ratos Wistar adultos.

The aim of this work was to evaluate the ivermectin effect on the testicular parenchyma through the daily spermatic production and the efficiency of the spermatogenesis in adult Wistar rats treated with different dosages (200, 400 and 600æg/kg) of ivermectin. Based on the histomorfometric evaluation, ivermectin had no deleterious effect on the testicular parenchyma and spermatogesis, which one was confirmed through the maintenance of the daily spermatic input and intrinsic income of spermatogenesis (PED/g/t), as well as by the maintenance of the testicular parenchyma structure. Based on the quantitative and qualitative results of spermatogenesis, it is possible to conclude that ivermectin does not have toxic-degenerative effect on the testicular parenchyma of adult Wistar rats.

Osteossarcoma de patela em cão. Relato de caso

O artigo não apresenta resumo.

Use of nucleotides in weanling rats with diarrhea induced by a lactose overload: effect on the evolution of diarrhea and weight and on the histopathology of intestine, liver and spleen

Until recently, dietary sources of nucleotides were thought not to be essential for good nutrition. Certain states with higher metabolic demands may require larger amounts that cannot be provided by endogenous production. The objective of the present study was to determine the action of nucleotides on the recovery from lactose-induced diarrhea in weaned rats. Thirty-six weanling Fisher rats were divided into two groups. Group 1 received a standard diet and group 2 received a diet containing lactose in place of starch. On the 10th day, six animals per group were sacrificed for histopathological evaluation. The remaining animals were divided into two other subgroups, each with 6 animals, receiving a control diet, a control diet with nucleotides (0.05 percent adenosine monophosphate, 0.05 percent guanosine monophosphate, 0.05 percent cytidine monophosphate, 0.05 percent uridine monophosphate and 0.05 percent inosine monophosphate), a diet with lactose, and a diet with lactose and nucleotides. On the 32nd day of the experiment all animals were sacrificed. Animals with diarrhea weighed less than animals without diarrhea. The introduction of nucleotides did not lead to weight gain. Mean diet consumption was lower in the group that continued to ingest lactose, with the group receiving lactose plus nucleotides showing a lower mean consumption. Animals receiving lactose had inflammatory reaction and deposits of periodic acid-Schiff-positive material in intestinal, hepatic and splenic tissues. The introduction of nucleotides led to an improvement of the intestinal inflammatory reaction. In lactose-induced diarrhea, when the stimulus is maintained - lactose overload - the nucleotides have a limited action on the weight gain and on recovery of intestinal morphology, although they have a protective effect on hepatic injury and improve the inflammatory response

Effect of medroxyprogesterone acetate on thyrotropin secretion in adult and old female rats

Steroid hormones have been implicated in the modulation of TSH secretion; however, there are few and controversial data regarding the effect of progesterone (Pg) on TSH secretion. Medroxyprogesterone acetate (MPA) is a synthetic alpha-hydroxyprogesterone analog that has been extensively employed in therapeutics for its Pg-like actions, but that also has some glucocorticoid and androgen activity. Both hormones have been shown to interfere with TSH secretion. The objective of the present study was to investigate the effects of MPA or Pg administration to ovariectomized (OVX) rats on in vivo and in vitro TSH release and pituitary TSH content. The treatment of adult OVX rats with MPA (0.25 mg/100 g body weight, sc, daily for 9 days) induced a significant (P<0.05) increase in the pituitary TSH content, which was not observed when the same treatment was used with a 10 times higher MPA dose or with Pg doses similar to those of MPA. Serum TSH was similar for all groups. MPA administered to OVX rats at the lower dose also had a stimulatory effect on the in vitro basal and TRH-induced TSH release. The in vitro basal and TRH-stimulated TSH release was not significantly affected by Pg treatment. Conversely, MPA had no effect on old OVX rats. However, in these old rats, ovariectomy alone significantly reduced (P<0.05) basal and TRH-stimulated TSH release in vitro, as well as pituitary TSH content. The results suggest that in adult, but not in old OVX rats, MPA but not Pg has a stimulatory effect on TSH stores and on the response to TRH in vitro

Interaction between substance P and gastrin-releasing peptide on thyrotropin secretion by rat pituitary in vitro

The effect of substance P (SP) on thyrotropin (TSH) secretion is controversial. In this study we evaluated the effect of SP on TSH secretion by hemipituitaries of 3-month-old Wistar rats in vitro and its interaction with gastrin-releasing peptide (GRP) at equimolar concentrations (1 µM and 10 µM). TSH release was measured under basal conditions and 30 min after incubation in the absence or presence of SP, GRP or both peptides. Pituitary TSH content was also measured in the pituitary homogenate after incubation. SP at both concentrations caused a significant (P<0.05) increase in TSH secretion compared with all other groups, which was approximately 60 percent (1 µM) and 85 percent (10 µM) higher than that of the control group (23.3 + or - 3.0 ng/ml). GRP at the lower concentration did not produce a statistically significant change in TSH secretion, whereas at the concentration of 10 µM it produced a 50 percent reduction in TSH. GRP co-incubated with substance P completely blocked the stimulatory effect of SP at both concentrations. Pituitary TSH content decreased in the SP-treated group compared to controls (0.75 + or - 0.03 µg/hemipituitary) at the same proportion as the increase in TSH secretion, and this effect was also blocked when GRP and SP were co-incubated. In conclusion, in an in vitro system, SP increased TSH secretion acting directly at the pituitary level and this effect was blocked by GRP, suggesting that GRP is more potent than SP on TSH secretion, and that this inhibitory effect could be the predominant effect in vivo

Effects of estradiol benzoate on 5'-iodothyronine deiodinase activities in female rat anterior pituitary gland, liver and thyroid gland

There is little information on the possible effects of estrogen on the activity of 5'-deiodinase (5'-ID), an enzyme responsible for the generation of T3, the biologically active thyroid hormone. In the present study, anterior pituitary sonicates or hepatic and thyroid microsomes from ovariectomized (OVX) rats treated or not with estradiol benzoate (EB, 0.7 or 14 mug/100 g body weight, sc, for 10 days) were assayed for type I 5'-ID (5'-ID-I) and type II 5'-ID (5'-ID-II, only in pituitary) activities. The 5'-ID activity was evaluated by the release of (125)I from deiodinated (125)I rT3, using specific assay conditions for type I or type II. Serum TSH and free T3 and free T4 were measured by radioimmunoassay. OVX alone induced a reduction in pituitary 5'-ID-I (control = 723.7 + 67.9 vs OVX = 413.9 + 26.9; P<0.05), while the EB-treated OVX group showed activity similar to that of the normal group. Thyroid 5'-ID-I showed the same pattern of changes, but these changes were not statistically significant. Pituitary and hepatic 5'-ID-II did not show major alterations. The treatment with the higher EB dose (14 mug), contrary to the results obtained with the lower dose, had no effect on the reduced pituitary 5'-ID-I of OVX rats. However, it induced an imporatnt increment of 5'-ID-I in the thyroid gland (0.8 times higher than that of the normal group: control = 131.9 + 23.7 vs OVX + EB 14 mug = 248.0 + 31.2; P<0.05), which is associated with increased serum TSH (0.6-fold vs OVX, P<0.05) but normal serum free T3 and free T4. The data suggest that estrogen is a physiological stimulator of anterior pituitary 5'-ID-I and a potent stimulator of the thyroid enzyme when employed at high doses.

Dose-dependent effects of 17-beta-estradiol on pituitary thyrotropin content and secretion in vitro

We studied the basal and thyrotropin-releasing hormone (TRH) (50 nM) induced thyrotropin (TSH) release in isolated hemipituitaries of ovariectomized rats treated with near-physiological or high doses of 17-Beta-estradiol benzoate (EB; sc, daily for 10 days) or with vehicle (untreated control rats, OVX). One group was sham-operated (normal control). The anterior pituitary glands were incubated in Krebs-Ringer bicarbonate medium, pH 7.4 at 37 C in an atmosphere of 95 percent O2/5 percent CO2. Medium and pituitary TSH was measured by specific RIA (NIDDK-RP-3). Ovariectomy induced a decrease (P<0.05) in basal TSH release (normal control = 44.1 + 7.2; OVX = 14.7 + 3.0 ng/ml) and tendend to reduce TRH-stimulated TSH release (normal control = 33.0 + 8.1; OVX = 16.6 + 2.4 ng/ml). The lowest dose of EB (0.7 mug/100 g body weight) did not reverse this alteration, but markedly increased the pituitary TSH content (0.6 + 0.06 mug/hemipituitary; P<0.05) above that of OVX (0.4 + 0.03 mug/hemipituitary) and normal rats (0.46 + 0.03 mug/hemipituitary). The intermediate EB dose (1.4 mug/100 g body weight) induced a nonsignificant tendency to a higher TSH response to TRH compared to OVX and a lower response compared to normal rats. Conversely, in the rats treated with the highest dose (14 mug/100 g body weight), serum 17-Beta-estradiol was 17 times higher than normal, and the basal and TRH-stimulated TSH release, as well as the pituitary TSH content, was significantly (P<0.05) reduced compared to normal rats and tended to be even lower than the values observed for the vehicle-treated OVX group, suggesting an inhibitory effect of hyperestrogenism. In conclusion, while reinforcing the concept of a positive physiological regulatory role of estradiol on the tSH response to TRH and on the pituitary stores of the hormone, the present results suggest an inhibitory effect of high levels of estrogen on these responses.

Acute effect of thyroxine on pituitary neuromedin B content of hypothyroid rats and its correlation with TSH secretion

Neuromedin B (NB) is a bombesin-like peptide that has been recently characterized as a physiological paracrine/autocrine inhibitor of thyrotropin (TSH) secretion. We report here the time course of the effect of thyroxine (T4) administration to hypothyroid rats on the anterior pituitary content of NB. Dutch-Miranda male rats weighing 250-300 g received 0.03 percent methimazole in the drinking water for 3 weeks. T4(0.8µg/100 g body weigh, sc) was given 1/2, 1,2 or 6 h before sacrifice. One group recived saline rather than T4 (hypothyroid control). The groups contained 6 to 8 animals each. NB, extracted from tissue by boiling in acetic acid, was measured by radioimmunoassay, using a highly specific anti-serum. Pituitary NB content was significantly increased 4-fold, as ealry 1/2 h after T4 injection, while serum TSH level was similar to that of the hypophyroid control group. The peak response to T4 was at 4 h after injection, when NB content was increased 8-fold (hypothyroid: 45 ñ 8; 1/2h, 223 ñ 15; 1h, 203 ñ 48; 3h, 383 ñ 31; 6h, 224 ñ 30 fmol/mg protein) and serum TSH decreased to the level of normal rats (0.93-1.5 ng/ml) generally observed in our laboratory (jypothyroid: 31 ñ 3; 1/2h, 26 ñ 3; 1h, 31 ñ 2; 3h, 1.3 ñ 0.1; 6h, 3.7 ñ 0.6 ng/ml). These data suggest that NB synthesis is rapidly induced by thyroxine and this might represent a new regulatory pathy involved in the acute inhibitory effect of thyroid hormones on TSH secretion

Paradoxical effect of neuromedin B and thyroxin on thyrotropin secretion from isolated hyperthyroid pituitaries

Neuromedin B (NB) is a bombesin-like peptide that we recently characterized as a physiological autocrine inhibitor of thyrotropin (TSH) secretion. We now report the effect of NB, thyroxin (T4) and NB + thyroxin on basal and THR (50 nM)-stimulated TSH release from isolated hemipituitaries of hyperthyroid rats. To induce hyperthyroidism, 20 rats were treated with 0.03 per cent methimazole for one month and then received T4, 4 micrograms/100 g body weight, sc, daily for 7 days. Each experimental group consisted of 7 to 9 hemipituitaries. TSH was measured using a rat TSH kit provided by NIDDK. Basal TSH release was paradoxically increased in the presence of 0.1 microM T4 or 0.1 microM NB and even two times higher in the presence of both (Control: 30.0 +/- 4.2 ng/ml; T4: 58.6 +/- 5.6 ng/ml; NB: 53.4 +/- 6.1 ng/ml; T4 + NB: 90.4 +/- 8.5 ng/ml). The percent increment above basal TSH levels after TRH was higher only in the presence of NB (Control: 44.5 +/- 8.2 per cent , NB: 105.3 +/- 18.8 per cent ; P < 0.05). Altered responsiveness in hyperthyroidism and direct modification of the intracellular metabolism of T4 are mechanisms that could explain this paradoxical effect

Nailford capillaroscopy in diabetes mellitus: morphological abnormalities and relationship with microangiopathy

the morphology and density of nailfold capillaries were evaluated in patients with Type I and Type II diabetes mellitus and in healthy controls, using videocapillaroscopy. A protocol of well-defined capillary patterns was used. Diabetic patients had more tortuous and enlarged capillaries than controls. Nodular apical elongation was found only in diabetics and was more frequent in patients with a longer history of disease. Type II diabetic patientes with chronic clinical complications had a higher frequency of enlarged capillaries and nodular apical elongation. Glycemic control was without influence. Capillary densitu did not differ among the groups