Effect of increasing doses of chitosan to grazing beef steers on the relative population and transcript abundance of Archaea and cellulolytic and amylolytic bacterias.

This paper aims to investigate the influence of increasing chitosan doses on the relative proportion and abundance of cellulotytic, amylolytic bacteria, and Archaea transcripts for grazing cattle. Five rumen cannulated crossbread steers [3.6 months and 300 ± 25 kg body LW (live weight), mean ± standard deviation] were used in a 5 × 5 latin square design, randomly assigned to treatment sequence containing chitosan added to 0, 400, 800, 1200, or 1600 mg/kg concentrate. There was the effect of chitosan on the population of Fibrobacter succinogenes, Ruminococcus albus, and Archaea. The lowest population of these bacteria of 576.60 mg/kg DM (dry matter), 1010.40 mg/kg DM, and 634.80 mg/kg DM were noted when chitosan was added at levels of 3.87, 4.16, and 3.52. Except for Ruminococcus albus, which was not affected by increasing chitosan doses, supplementation of this additive in the concentrate quadratically increased the relative abundance of Fibrobacter succinogenes and Archaea Supplemental 740 mg CHI/kg concentrate for grazing steers receiving concentrate at 150 grams/100 kg LW is recommended to promote minimal effect on the relative population and abundance of cellulolytics and amylomatics and to restrict Archaea growth.

Beta-Cyclodextrins as affordable antivirals to treat coronavirus infection

The SARS-CoV-2 pandemic made evident that we count with few coronavirus-fighting drugs. Here we aimed to identify a cost-effective antiviral with broad spectrum activity and high safety and tolerability profiles. We began elaborating a list of 116 drugs previously used to treat other pathologies or characterized in pre-clinical studies with potential to treat coronavirus infections. We next employed molecular modelling tools to rank the 44 most promising inhibitors and tested their efficacy as antivirals against a panel of and {beta} coronavirus, e.g., the HCoV-229E and SARS-CoV-2 viruses. Four drugs, OSW-1, U18666A, hydroxypropyl-{beta}-cyclodextrin (H{beta}CD) and phytol, showed antiviral activity against both HCoV-229E (in MRC5 cells) and SARS-CoV-2 (in Vero E6 cells). The mechanism of action of these compounds was studied by transmission electron microscopy (TEM) and by testing their capacity to inhibit the entry of SARS-CoV-2 pseudoviruses in ACE2-expressing HEK-293T cells. The entry was inhibited by H{beta}CD and U18666A, yet only H{beta}CD could inhibit SARS-CoV-2 replication in the pulmonary cells Calu-3. With these results and given that cyclodextrins are widely used for drug encapsulation and can be safely administered to humans, we further tested 6 native and modified cyclodextrins, which confirmed {beta}-cyclodextrins as the most potent inhibitors of SARS-CoV-2 replication in Calu-3 cells. All accumulated data points to {beta}-cyclodextrins as promising candidates to be used in the therapeutic treatments for SARS-CoV-2 and possibly other respiratory viruses.

Unraveling the antiviral activity of plitidepsin by subcellular and morphological analysis

The pandemic caused by the new coronavirus SARS-CoV-2 has made evident the need for broad-spectrum, efficient antiviral treatments to combat emerging and re-emerging viruses. Plitidepsin is an antitumor agent of marine origin that has also shown a potent pre-clinical efficacy against SARS-CoV-2. Plitidepsin targets the host protein eEF1A (eukaryotic translation factor 1 alpha 1) and affects viral infection at an early, post-entry step. Because electron microscopy is a valuable tool to study virus-cell interactions and the mechanism of action of antiviral drugs, in this work we have used transmission electron microscopy (TEM) to evaluate the effects of plitidepsin in SARS-CoV-2 infection in cultured Vero E6 cells 24 and 48h post-infection. In the absence of plitidepsin, TEM morphological analysis showed double-membrane vesicles (DMVs), organelles that support coronavirus genome replication, single-membrane vesicles with viral particles, large vacuoles with groups of viruses and numerous extracellular virions attached to the plasma membrane. When treated with plitidepsin, no viral structures were found in SARS-CoV-2-infected Vero E6 cells. Immunogold detection of SARS-CoV-2 nucleocapsid (N) protein and double-stranded RNA (dsRNA) provided clear signals in cells infected in the absence of plitidepsin, but complete absence in cells infected and treated with plitidepsin. The present study shows that plitidepsin completely blocks the biogenesis of viral replication organelles and the morphogenesis of virus progeny. Electron microscopy morphological analysis coupled to immunogold labeling of SARS-CoV-2 products offers a unique approach to understand how antivirals such as plitidepsin work.

Degradability, in vitro fermentation parameters, and kinetic degradation of diets with increasing levels of forage and chitosan.

Chitosan is the second most important natural biopolymer in the world, extracted from crustaceans, shrimps, and crabs and can modulate rumen fermentation. Our hypothesis is that the addition of chitosan alters the fermentation patterns of different diets for ruminants. This study aimed to evaluate the effects of different levels of chitosan and forage on in vitro dry degradation kinetics and fermentation in a gas production system. The chitosan levels (0, 1625, 3,500, or 7,500 mg/kg of dry matter [DM]) were arranged in a completely randomized block design, and for in vitro ruminal fermentation assay, we used a split splot arrangement. Into the incubator, all chitosan levels were distributed in the four jars, and the forage levels varying on 100, 65, 50, 35, and 20 on DM basis. There was an interaction effect for chitosan and forage levels (P ≤ 0.05) on IVDMD; IVOMD. IVDCP and IVDNDF. Chitosan negatively affected IVDMD in all roughage levels evaluated. The pH and ammonia concentration present effect only for roughage levels and incubation hours. The chitosan did not change (P = 0.3631) the total short-chain fatty acid concentration (overall mean = 21.19 mmol/L) and the C2:C3 ratio (overall mean = 5.85). The IVDCP showed the same decreasing quadratic behavior (P < 0.0001). The increasing chitosan addition increases (P < 0.0001) the gas production and decreases (P < 0.0001) the lag time (parameter C) of diets with greater concentrate participation, characterizing greater efficiency in the degradability of the diet, confirming its potential use in diets for ruminants. Chitosan changes in vitro dry degradation kinetics and fermentation at the minimum dose of 1,722 mg/kg DM for all diets. The roughage level influenced the in vitro nutrients degradability and cumulative gas production.

Potential degradation and colonization time of ruminal microorganisms on the particles of different oilseeds-crushed, and its chemical composition

This study was carried out to evaluate by-product of the biodiesel industry as canola, safflower, forage turnip, and soybean crushed on the chemical composition, in situ degradability, and colonization time. Canola (Brassica napus L. var. oleifera), safflower (Carthamus tinctorius L.), forage turnip (Raphanus stivus L. var. oleiferus Metzg), and soybean (Glycine max) grains went through the oil extraction process by means of a cold pressing, resulting in the oilseeds-crushed. The treatments identification included: CAN ­ Canola crushed; SAF ­ Safflower crushed; TUR ­ Forage turnip crushed; and SOY ­ Soybean crushed. The oilseed-crushed treatments were quantified about mineral (calcium, magnesium, copper, iron, manganese, zinc, phosphorus and potassium), chemical composition (dry matter, ash, organic matter, crude protein, ether extract, neutral detergent fiber, acid detergent fiber, total carbohydrates, non-fibrous carbohydrates, and total digestible nutrient contents), In situ degradability, and colonization time. Magnesium, phosphorus, and zinc showed the greater values for TUR treatment 3.46, 27.4, 39.8, respectively, when compared to the other oilseed-crushed treatments. The TUR treatment had the lowest organic matter, whereas had the greater (p≤0.05; TUR and SOY treatments) for the non-fibrous carbohydrates. Ether extract was not affected (p>0.05) with the different oilseed-crushed treatments. Neutral detergent fiber was affected (p≤0.05) for CAN and SAF treatments with the greater values, 344 and 500 g/kg of dry matter, respectively. Soluble and potentially degradable fractions for SAF treatment showed similar results. Whereas the constant rate of degradation, presented the lowest value when compared to the other treatments. Effective degradability of crude protein was greater for CAN 63.2% than SOY 65.9% treatment, which had the lowest value. Potential degradability of crude protein did not differ between treatments. Colonization time for dry matter and crude protein were similar between TUR and SOY treatments. In conclusion, oilseeds-crushed from the biodiesel production can be targeted/used, as feed with great protein and energetic potential in the ruminant's production, considering the need of correct formulation and ingredients knowledge.

Fatty acids profile, atherogenic and thrombogenic health lipid indices in the meat of lambs that received canola grain / Perfil de ácidos graxos, índices de lipídios aterogênicos e trombogênicos em carne de cordeiros alimentados com grãos de canola

This study evaluated the fatty acid composition and qualitative characteristics of meat from lambs feed in feedlot with increasing levels of canola grain. Meat obtained from 27 lambs fed 0, 8 and 16% inclusion of canola grain were analyzed. There was a reduction in the content of saturated fatty acids (SFA): lauric, heptadecanoic, and stearic; and unsaturated fatty acids (UFA): palmitoleic, oleic, and eicosatrienoic, with the increasing levels of canola grain. There was a linear reduction for the ω3 acid and the ω3: ω6 ratio, while the ω6: ω3 ratio increased. But the values observed for this ratio (ω6: ω3) were lower than 4, which is considered a satisfactory value. There was a slight increase (~2%) for the thrombogenicity index and atherogenicity index with the inclusion of canola grain. There was a reduction in the hypocholesterolemic: hypercholesterolemic ratio, with mean values of 2.09 for the diet with 0% inclusion, and 2.06 for 8 and 16% inclusion of canola. Although the inclusion of canola grain for lambs decreased the content of some UFA, reflecting alterations in the correlated nutritional properties, there is a reduction of SFA. The results for instrumental analysis, proximate composition, and sensory acceptance of the lamb meat were similar among the treatments.(AU)

Objetivou-se avaliar a composição dos ácidos graxos e as características qualitativas da carne de cordeiros terminados com níveis crescentes de canola grão na dieta. Foram estudadas amostras de carne provenientes de 27 cordeiros, confinados por 45 dias e alimentados com 00, 08 e 16% de inclusão de canola grão. Houve efeito para os ácidos graxos saturados (AGS): laurico, heptadecanoico e esteárico; ácidos graxos monoinsaturados (AGMI): palmitoleico e oleico; e ácidos graxos polinsaturados (AGPI): eicosatrienoico. Estes ácidos reduziram à medida que os níveis da canola grão aumentaram. Para os AGMI, houve efeito com maior concentração no músculo dos cordeiros alimentados sem a canola grão (49,80%). Houve uma redução linear para o ácido ω3 e para a relação ω3:ω6, enquanto que a relação ω6:ω3 aumentou. A canola grão influenciou o índice de aterogenicidade, com média de 0,57 para o tratamento com 0% de inclusão e 0,58 para os tratamentos com 8% e 16% de inclusão. Observou-se aumento linear para o índice de trombogenicidade com a inclusão da canola grão, cujas médias foram, respectivamente, 0,16, 0,17 e 0,18 para os tratamentos 0%, 8% e 16% de inclusão. Houve redução para a relação hipocolesterolêmicos-hipercolesterolêmicos, com médias de 2,09 para a dieta com 0% de inclusão, e 2,06 para 8% e 16% de inclusão da canola em grão na dieta. A canola grão não influenciou a análise instrumental, composição centesimal e atributos sensoriais da carne.(AU)

Nandrolone decanoate is prooxidant in the myocardium of exercised or sedentary rats / Decanoato de nandrolona é pro-oxidante no miocárdio de ratos treinados e sedentários / Decanoato de nandrolona es prooxidante en el miocardio de ratones entrenados y sedentarios

ABSTRACT Introduction: Nandrolone decanoate is a synthetic testosterone analogue considered one of the most widely used anabolic androgenic steroids (AAS) among adolescents and athletes. Chronic ingestion of AAS increases the incidence of cardiovascular abnormalities in athletes, but the mechanism that causes these changes remains unknown. Objectives: The purpose of this study is to verify the possible effects of the use of anabolic androgenic steroids (AAS) on the morphology and oxidative metabolism of the heart in exercised and sedentary rats. Methods: This is a comparative prospective level II study. Twenty-four Wistar rats were distributed in groups that performed voluntary (TG) and sedentary (SG) running exercises, and used AAS: the Anabolic Training Group (ATG), and the Anabolic Sedentary Group (ASG). During the three months of the running protocol, the animals received an intramuscular injection of 5 mg/kg b.p. of AAS. After the training period, the rats were euthanized and the hearts were removed for evaluation of lipid peroxidation and antioxidant capacity, and for morphometric analysis. Results: The anabolic groups, ASG (0.3072 ± 0.0531) and ATG (0.2732 ± 0.0413), presented higher lipid peroxidation when compared to the non-anabolic groups SG (0.1705 ± 0.0224) and TG (0.1785 ± 0.0340). Conclusion: There was no change in total antioxidant capacity or in the thickness of the interventricular septum and left ventricular wall. Thus, the use of anabolic androgenic steroids did not cause morphological changes in the myocardium. However it did alter the oxidative metabolism. It was also verified that aerobic exercise had no protective effect against lipid peroxidation in the myocardium caused by the use of AAS. Level of evidence II; Prospective comparative study.

RESUMO Introdução: O decanoato de nandrolona é um análogo sintético da testosterona, considerado um dos esteroides anabólicos androgênicos (EAA) mais utilizados entre adolescentes e atletas. Sua ingestão crônica aumenta a incidência de anormalidades cardiovasculares em atletas, porém o mecanismo que causa essas alterações ainda permanece desconhecido. Objetivos: O estudo teve como objetivo verificar os possíveis efeitos do uso de esteroides anabólicos androgênicos (EAA) na morfologia e no metabolismo oxidativo do coração de ratos treinados e sedentários. Métodos: Trata-se de um estudo prospectivo comparativo nível II. Vinte e quatro ratos Wistar foram distribuídos em grupos que realizaram exercícios de corrida voluntária (GT) e sedentários (GS) e faziam uso dos EAA, Grupo Treinado com Anabolizante (GTA) e Grupo Sedentário com Anabolizante (GSA). Durante os três meses do protocolo de corrida, os animais receberam injeção intramuscular de 5 mg/kg p.c. de EAA. Após o período de treinamento, houve a eutanásia e remoção do coração dos ratos para avaliação da peroxidação lipídica e capacidade antioxidante, além da análise morfométrica. Resultados: Verificaram-se que os grupos anabolizantes, GSA (0,3072 ± 0,0531) e GTA (0,2732 ± 0,0413), apresentaram maior peroxidação lipídica quando comparados aos grupos não anabolizantes GS (0,1705 ± 0,0224) e GT (0,1785 ± 0,0340). Conclusões: Não houve alteração na capacidade antioxidante total, assim como não houve alteração na espessura do septo interventricular e da parede ventricular esquerda. Portanto, o uso de esteroides anabólicos androgênicos não provocou alterações morfológicas no miocárdio, contudo alterou o metabolismo oxidativo. Verificou-se também que a prática de exercício aeróbico não teve efeito protetor contra a peroxidação lipídica no miocárdio provocada pelo uso dos EAA. Nível de evidência II; Estudo prospectivo comparativo.

RESUMEN Introducción: El decanoato de nandrolona es un análogo sintético de la testosterona considerado uno de los esteroides anabólicos androgénicos (EAA) más utilizados entre los adolescentes y atletas. Su ingestión crónica aumenta la incidencia de anomalías cardiovasculares en atletas, aunque el mecanismo que causa esas alteraciones sigue siendo desconocido. Objetivos: El estudio tuvo como objetivo verificar los posibles efectos del uso de esteroides anabólicos androgénicos (EAA) en la morfología y en el metabolismo oxidativo del corazón de ratones entrenados y sedentarios. Métodos: Se trata de un estudio prospectivo comparativo nivel II. Fueron distribuidos 24 ratones Wistar en grupos que realizaron ejercicios de carrera voluntaria (GE) y sedentarios (GS), y hacían uso de los EAA, Grupo Entrenado con Anabolizante (GEA) y Grupo Sedentario con Anabolizante (GSA). Durante los tres meses del protocolo de carrera, los animales recibieron inyección intramuscular de 5 mg/kg p.c. de EAA. Después del período de entrenamiento, hubo la eutanasia y remoción del corazón de los ratones, para evaluación de la peroxidación lipídica y capacidad antioxidante, además del análisis morfométrico. Resultados: Se verificó que los grupos anabolizantes, GSA (0,3072 ± 0,0531) y GEA (0,2732 ± 0,0413), presentaron mayor peroxidación lipídica cuando comparados a los grupos no anabolizantes GS (0,1705 ± 0,0224) y GE (0,1785 ± 0,0340). Conclusiones: No hubo alteración en la capacidad antioxidante total, así como no hubo alteración en el espesor del septo interventricular y de la pared ventricular izquierda. Por lo tanto, el uso de esteroides anabólicos androgénicos no provocó alteraciones morfológicas en el miocardio, aunque alteró el metabolismo oxidativo. Se verificó también que la práctica de ejercicio aeróbico no tuvo efecto protector contra la peroxidación lipídica en el miocardio provocada por el uso de EAA. Nivel de evidencia II; Estudio prospectivo comparativo.

The crambe (Crambe abyssinica Hochst) byproducts, can be used as a source of non-degradable protein in the rumen? / Coprodutos de crambe (Crambe abyssinica Hochst) podem ser utilizados como fonte de proteina não degrádavel no rúmen?

To evaluated the chemical composition and ruminal degradability of crambe byproducts (meal and crushed) and proteic supplements formulated with crushed crambe (0; 2.5; 5; 10 and 15%); five crossbred steers with average weight of 485±14 kg, were used. All the animal were kept in individual paddocks of 0.25 ha on Urochloa brizantha (syn. Brachiaria brizantha). It was observed a greater soluble fraction, higher effective degradability at 5%/h and higher degradation rate "c" and, consequent, lower indigestible fraction for crambe crushed ground in the sieve of 3 mm. The effective degradability at 5%/h was lower for the crambe crushed (55.42) in relation to the meal (48.80). The diet with 5% of inclusion of crambe showed higher effective degradability for dry matter (54.86%) and lower fraction "I" (30.64%) associated with higher fractions "c" and "b". Crambe ground in sieves of 1 and 3 mm mesh presented the highest degradability. Crushed crambe showed higher ruminal degradation than crambe meal; the crambe byproducts possibility can be use as a source of non-degradable protein in the rumen.

Para se avaliar a composição química, degradabilidade ruminal, o tempo da colonização da torta e do farelo de crambe e de suplementos protéico compostos de torta de crambe (0; 2,5; 5,0; 10 e 15%); foram utilizados cinco novilhos mestiços, com peso médio de 485 ± 14 kg. Todos os animais foram mantidos em piquetes individuais de 0,25 ha em pastagens de Urochloa brizantha (syn. Brachiaria brizantha). Observou-se uma fração solúvel maior, maior degradabilidade efetiva para a taxa de passagem de 5% / h e maior taxa de degradação "c" e, consequentemente, menor fração indigerível para a torta de crambe moído na peneira de 3 mm. A degradabilidade efetiva a 5% / h foi menor para a torta de crambe (55,42) em relação ao farelo (48,80). A dieta com adição de 5% de torta de crambe apresentou maior degradabilidade efetiva da matéria seca (54,86%) e menor fração "I" (30,64%), associada com as frações mais elevadas "c" e "b". A torta de Crambe moída em peneiras de 1 e 3 mm de diâmetro apresentaram os maiores valores de degradabilidade. A torta de apresenta maior degradação ruminal que o farelo de crambe. Os coprodutos de crambe possivelmente podem ser usados como fonte de proteína não degradada no rúmen.

Estratégias de enfrentamento utilizadas pelo paciente com deficiências físicas na hanseníase / Coping strategies used by the patient with physical disabilities in leprosy

O conhecimento das estratégias de coping (enfrentamento) usado nessas condições auxilia o indivíduo a lidar com as limitações decorrentes da hanseníase. O objetivo deste estudo foi avaliar tais estratégias utilizadas pelos referidos pacientes, bem como verificar as dificuldades na realização das atividades de vida diária (AVDs) e das atividades instrumentais de vida diária (AIVDs). Trata-se de um estudo descritivo, com 30 pacientes com hanseníase avaliados no Instituto Lauro de Souza Lima/Bauru/SP. Foram utilizados na coleta de dados: um questionário sobre os dados sociodemográficos, aspectos clínicos da doença e a independência funcional na execução das AVDs e AIVDs; checklist relacionado ao tipo de deficiência física visível encontrada no paciente; e o Inventário de Estratégias de Coping de Folkman e Lazarus, adaptado para o português. A idade média dos pacientes foi de 55 anos. Houve predomínio dos pacientes do gênero masculino (60%), com Ensino Fundamental I (70%), residentes com as famílias (76,7%) e afastados do trabalho (90%). A maioria deles era multibacilar (96,7%) e o tratamento poliquimioterapia havia sido concluído (83,3%). As dificuldades funcionais mais frequentes (80%) nas AVDs foram: locomoverse, vestir­se, realizar transferência e higiene pessoal; e, nas AIVDs foram: administrar o ambiente doméstico, cuidar da casa e da roupa. O uso de estratégias positivas, como a resolução de problemas e suporte social está relacionado à boa adaptação biopsicossocial do indivíduo, considerando-se que a maioria não utilizava o confronto. Entretanto, uma parcela expressiva de pacientes utilizava as estratégias de autocontrole, fuga e esquiva.

The knowledge of the coping strategies used in these conditions helps the individual to deal with the limitations caused by leprosy. The aim of this study was to evaluate these strategies used by patients, weel with check the difficulties in to performe the daily living activities (DLA) and daily living instrumental activities (DLIA). This is a descriptive study with 30 patients with leprosy patients evaluated at Lauro de Souza Lima Institute/Bauru/SP. It was used to collect the data, a questionnaire about sociodemographic data, clinical aspects of the disease and the functional independence in the achievement of DLA and DLIA; a checklist related to the visible physical disability found in patients; an Inventory of Coping Strategies of Folkman and Lazarus, adapted to the Portuguese language. The middle age of patients was 55 years old. There was a predominance of male patients (60%), with Elementary school (70%), living with their families (76.7%) and off to the work (90%). Most of the patients were multibacillary (96.7%) and the multidrug therapy had been completed (83.3%). The most frequent functional difficulties in DLA (80%) were: getting yourself, put on clothes, to transfer and personal hygiene; and in DLIA were: manage the home environment, caring for the home and clothe. The use of positive strategies, such as problem solving and social support is related to a good biopsychosocial adaptation of the individual, considering that the most of the individual do did not use the confrontation. However, a significant portion of patients used the self-control strategies, escape and avoidance.

Lateral parabrachial afferent areas and serotonin mechanisms activated by volume expansion.

Recent evidence has shown that the serotonergic mechanism of the lateral parabrachial nucleus (LPBN) participates in the regulation of renal and hormonal responses to isotonic blood volume expansion (BVE). We investigated the BVE-induced Fos activation along forebrain and hindbrain nuclei and particularly within the serotonergic clusters of the raphé system that directly project to the LPBN. We also examined whether there are changes in the concentration of serotonin (5HT) within the raphé nucleus in response to the same stimulus. With this purpose, we analyzed the cells doubly labeled for Fos and Fluorogold (FG) following BVE (NaCl 0.15 M, 2 ml/100 g b.w., 1 min) 7 days after FG injection into the LPBN. Compared with the control group, blood volume-expanded rats showed a significant greater number of Fos-FG double-labeled cells along the nucleus of the solitary tract, locus coeruleus, hypothalamic paraventricular nucleus, central extended amygdala complex, and dorsal raphé nucleus (DRN) cells. Our study also showed an increase in the number of serotonergic DRN neurons activated in response to isotonic BVE. We also observed decreased levels of 5HT and its metabolite 5-hydroxyindoleacetic acid (measured by high-pressure liquid chromatography) within the raphé nucleus 15 min after BVE. Given our previous evidence on the role of the serotonergic system in the LPBN after BVE, the present morphofunctional findings suggest the existence of a key pathway (DRN-LPBN) that may control BVE response through the modulation of 5HT release.

Estradiol reduces cumulative mercury and associated disturbances in the hypothalamus-pituitary axis of ovariectomized rats.

The aim of this research was to verify the incidence of endocrine dysfunction associated with mercury intoxication in the hypothalamus-pituitary reproductive system of normally cycling or castrated female rats and the possible protective action of estrogen replacement therapy. We found no differences in the frequency of estrus cycle stages (diestrus I, diestrus II, proestrus, and estrus) in normally cycling female rats during 54 days of daily oral administration of 0.004, 0.02, and 1 mg/kg MeHgCl. Conversely, the higher dose (1 mg/kg) induced a significant decrease in content of luteinizing hormone releasing hormone (LHRH) into the medial hypothalamus when administered daily during 3 days in ovariectomized rats. This effect was associated with increased levels of mercury found in the anterior pituitary gland and medial hypothalamus, rather than the anterior and posterior hypothalamus, striatum or cerebellum. A decrease in plasma levels of luteinizing hormone (LH) was also detected after administration of 7.5 mg/kg MeHgCl. These disturbances in LHRH and LH secretion induced by mercury were abolished or superimposed (respectively) by estrogenic replacement therapy (0.025 mg/kg 17beta estradiol cypionate, intramuscular). These effects were associated with a significant reduction in mercury content of the anterior pituitary gland and medial hypothalamus, suggesting a protective estrogenic effect.