Changes on corpus luteum structure and progesterone synthesis pathway after hCG or GnRH treatment during the early luteal phase in sheep.

This study investigated the effect of hCG or GnRH on structural changes of the corpora lutea (CL) and the regulation of the expression of steroidogenic enzymes involved in P4 secretion in post-ovulatory (po-CL) and accessory CL (acc-CL). Sixty-four ewes were assigned to three groups receiving: 300 IU of hCG (hCG) or 4 µg Buserelin (GnRH) or 1 mL of saline solution (Control) on Day (d) 4 post artificial insemination (FTAI). Laparoscopic ovarian were performed on d 4, 14 and, 21 post-FTAI to determine the numbers of CL. Blood samples were collected for serum LH and P4 analysis. On d 14 post-FTAI, both CL were removed from the ovary to determine large luteal cell (LLC) number and to evaluate the expression of steroidogenic enzymes (HSD3B1, STAR, CYP11A1). Only hCG and GnRH treated ewes generated acc-CL. The LLC in both po- and acc-CL were significantly greater in the hCG group compared to GnRH and Control groups (P<0.05). Overall, hCG group showed the greatest immunodetection of HSD3B1and STAR in both po- and acc-CL (P<0.05). rnRNA expression of HSD3B1, STAR and CYP11A1 in the acc-CL tended to be greater in hCG group than in GnRH group (P<0.1). The LH concentration was increased in GnRH group (P<0.05) and P4 concentration was greater in hCG group compared to the other groups (P<0.05). In conclusion, administration of hCG has a notably impact on acc-CL development and the expression of steroidogenic enzymes compared to GnRH treatment in ewes. This leads to elevated P4 concentration and improved luteal function.

Monitoring of Body Condition in Dairy Cows to Assess Disease Risk at the Individual and Herd Level.

A retrospective longitudinal study assessing the explanatory and predictive capacity of body condition score (BCS) in dairy cows on disease risk at the individual and herd level was carried out. Data from two commercial grazing herds from the Argentinean Pampa were gathered (Herd A = 2100 and herd B = 2600 milking cows per year) for 4 years. Logistic models were used to assess the association of BCS indicators with the odds for anestrus at the cow and herd level. Population attributable fraction (AFP) was estimated to assess the anestrus rate due to BCS indicators. We found that anestrus risk decreased in cows calving with BCS ≥ 3 and losing ≤ 0.5 (OR: 0.07-0.41), and that anestrus rate decreased in cohorts with a high frequency of cows with proper BCS (OR: 0.22-0.45). Despite aggregated data having a good explanatory power, their predictive capacity for anestrus rate at the herd level is poor (AUC: 0.574-0.679). The AFP varied along the study in both herds and tended to decrease every time the anestrous rate peaked. We conclude that threshold-based models with BCS indicators as predictors are useful to understand disease risk (e.g., anestrus), but conversely, they are useless to predict such multicausal disease events at the herd level.

Neuroendocrine control of brown adipocyte function by prolactin and growth hormone.

Growth hormone (GH) is fundamental for growth and glucose homeostasis, and prolactin for optimal pregnancy and lactation outcome, but additionally, both hormones have multiple functions that include a strong impact on energetic metabolism. In this respect, prolactin and GH receptors have been found in brown, and white adipocytes, as well as in hypothalamic centers regulating thermogenesis. This review describes the neuroendocrine control of the function and plasticity of brown and beige adipocytes, with a special focus on prolactin and GH actions. Most evidence points to a negative association between high prolactin levels and the thermogenic capacity of BAT, except in early development. During lactation and pregnancy, prolactin may be a contributing factor that limits unneeded thermogenesis, downregulating BAT UCP1. Furthermore, animal models of high serum prolactin have low BAT UCP1 levels and whitening of the tissue, while lack of Prlr induces beiging in WAT depots. These actions may involve hypothalamic nuclei, particularly the DMN, POA and ARN, brain centers that participate in thermogenesis. Studies on GH regulation of BAT function present some controversies. Most mouse models with GH excess or deficiency point to an inhibitory role of GH on BAT function. Even so, a stimulatory role of GH on WAT beiging has also been described, in accordance with whole-genome microarrays that demonstrate divergent response signatures of BAT and WAT genes to the loss of GH signaling. Understanding the physiology of BAT and WAT beiging may contribute to the ongoing efforts to curtail obesity.

A simple method to select high superovulatory responder goats.

In most female mammals, a common drawback to multiple ovulation embryo transfer programs is the variability in the superovulatory response to the multidose pFSH treatment. The aim of the present study was to identify embryo donor goats based on their response to superovulation before the performance of a high-cost hormonal treatment, as we have previously done in sheep. To this end, we evaluated the number of ovulations obtained in response to the administration of a one-shot eCG treatment and related it with the subsequent ovarian response to a multiple-dose pFSH treatment in 33 goats of the Criolla-Neuquina breed. Goats received a one-shot eCG treatment of 800 IU at the end of a 17-day progestational treatment; 9 days later, started a second 17-day progestational treatment and then received a multiple-dose pFSH treatment on days 15-17 (116 mg pFSH, in six decreasing doses). The number of corpora lutea (CL) per goat was recorded laparoscopically after both hormonal treatments. On day 8 after the second pessary removal, embryos were surgically recovered and classified by quality. Results showed a significant positive correlation between the number of CL obtained in response to the eCG and pFSH treatments (r = 0.41; y = 0.8352x + 6.9906; P < 0.05), although of limited value to select high ovulatory responding goats, due to its low correlation value. Then, goats were grouped into high and low ovulatory responders to the eCG (High ≥9; Low <9 CL) and pFSH treatments (High ≥13; Low <13 CL). After the eCG and pFSH treatments, 60% of the goats maintained their classification as high or low superovulatory responders (expressed as recurrence rate). Significant differences were found in the number of CL (18.2 ± 1.3 vs 9.9 ± 1.3), number of embryos + oocytes (13.5 ± 1.7 vs 7.6 ± 1.7), number of embryos (10.8 ± 1.4 vs 5.1 ± 1.4) and number of Grade 1 and Grade 2 embryos (8.8 ± 1.4 vs 4.3 ± 1.4) between high and low superovulatory responder goats (P < 0.05), while no differences were observed in the number of oocytes and in the recovery of embryos + oocytes, embryos, Grade 1 and Grade 2 embryos and fertilization rates (P > 0.05). In conclusion, the recurrence rate in ovarian response between the one-shot eCG treatment and the multiple-dose pFSH treatment would confirm the existence of an "individual or intrinsic factor" of the donor goat that would respond as a high or low ovulatory responder to superovulatory treatments.

A successful vitrification technique for goat morulae conservation.

The aim of this study was to evaluate the effect of different vitrification and warming processes on the in vitro embryo survival of caprine morulae, considering the day of recovery. A total of 136 morulae of Criolla-Neuquina goats recovered on Days 7 or 8 after sponge removal, were exposed to three different vitrification processes; V1 (n = 48): glycerol (G) + ethylene glycol (EG); V2 (n = 44): EG + 0.5 M sucrose and V3 (n = 44): G + EG + 0.5 M sucrose. The morulae of each vitrification process were randomly assigned to three warming processes; W1 (n = 45): 0.5 M sucrose at 25 °C; W2 (n = 44): 0.5 M sucrose at 39 °C; and W3 (n = 47): solution containing half the concentration of the cryoprotectants + 0.5 M sucrose at 25 °C. After, embryos were cultured in 100 µL TCM 199 drops under mineral oil, at 39 °C and a 6.5% CO2 atmosphere for 72 h according to the different treatments. There were no viable embryos in V1 and V2 in none of their three respective warmings. Only V3 showed an embryo survival rate to hatched blastocyst stage of 59.1%. When considering embryo survival according to the warming processes, the survival rate was higher in V3W2 (76.9%) and V3W3 (66.7%) groups compared to the V3W1 group (37.5%; P < 0.05). The embryo survival of V3 for Day 8 after sponge removal (81.3%) was higher compared to Day 7 (46.4%; P < 0.05). In conclusion, a successful embryo survival is obtained by using a combination of cryoprotectants (G + EG) with addition of sucrose in the vitrification process for conservation of caprine morulae in embryo transfer programs. The survival rates in vitro of vitrified-warmed morulae in goats were influenced by their recovery day. Further studies should be conducted to determine if these results are reproducible in vivo embryo transfer on field situations.

Age at First Gestation in Beef Heifers Affects Fetal and Postnatal Growth, Glucose Metabolism and IGF1 Concentration.

This study aimed to determine the effects of age at first gestation on offspring growth performance, glucose metabolism, and IGF1 concentration. Heifers impregnated by AI from a single bull at 15 months of age (15 M, n = 20), or 27 months of age (27 M, n = 20), and multiparous cows (adult, n = 20) were used. Dams from all groups were managed in a single group during gestation and lactation. Gestational length was longer in the 15 M and 27 M than in adult dams (p = 0.009). Bodyweight at birth, at weaning and ADG during lactation were higher in calves from adult dams than in those from 27 M dams, and higher in calves from the latter than in 15 M calves (p < 0.001). Calves from 15 M dams had an increased head circumference/BW ratio compared to calves from 27 M dams, while calves from this latter group had an increased ratio compared to calves from adults (p = 0.005). Body mass index was greater in calves from adults than in those from 15 M and 27 M dams (p = 0.002). Milk production from 15 M and 27 M dams was similar but lower than that from adults (p = 0.03). Calves born from adult dams had greater blood glucose concentrations than those from 15 M and 27 M dams (p < 0.05). Serum IGF1 concentrations were higher in calves from adults than in calves from 15 M and 27 M dams (p = 0.01). This study showed that age at first gestation affects offspring postnatal growth performance, glucose metabolism and IGF1 concentration.

Corrigendum to "Angiogenesis in Pituitary Adenomas: Human Studies and New Mutant Mouse Models".

[This corrects the article DOI: 10.1155/2014/608497.].

Epigenetic modifications in the GH-dependent Prlr, Hnf6, Cyp7b1, Adh1 and Cyp2a4 genes.

Many sex differences in liver gene expression originate in the brain, depend on GH secretion and may underlie sex disparities in hepatic disease. Because epigenetic mechanisms may contribute, we studied promoter methylation and microRNA abundance in the liver, associated with expression of sexual dimorphic genes in mice with selective disruption of the dopamine D2 receptor in neurons (neuroDrd2KO), which decreases hypothalamic Ghrh, pituitary GH, and serum IGFI and in neonatally androgenized female mice which have increased pituitary GH content and serum IGFI. We evaluated mRNA levels of the female predominant genes prolactin receptor (Prlr), alcohol dehydrogenase 1 (Adh1), Cyp2a4, and hepatocyte nuclear transcription factor 6 (Hnf6) and the male predominant gene, Cyp7b1. Female predominant genes had higher mRNA levels compared to males, but lower methylation was only detected in the Prlr and Cyp2a4 female promoters. In neuroDrd2KO mice, sexual dimorphism was lost for all genes; the upregulation (feminization) of Prlr and Cyp2a4 in males correlated with decreased methylation of their promoters, and the downregulation (masculinization) of Hnf-6 mRNA in females correlated inversely with its promoter methylation. Neonatal androgenization of females evoked a loss of sexual dimorphism only for the female predominant Hnf6 and Adh1 genes, but no differences in promoter methylation were found. Finally, mmu-miR-155-5p, predicted to target Cyp7b1 expression, was lower in males in association with higher Cyp7b1 mRNA levels compared to females and was not modified in neuroDrd2KO or TP mice. Our results suggest specific regulation of gene sexually dimorphic expression in the liver by methylation or miRNAs.

The Notch system during pubertal development of the bovine mammary gland.

The development of the mammary gland of cows during pre-weaning and puberty will condition its future productive capacity and warrants special study. In this respect, Notch signaling regulates tissue development and fate by modifying cell proliferation and differentiation and has been involved in stem cell maintenance, but has not been extensively studied in the developing mammary glands in cows. We therefore investigated Notch receptor expression and localization, as well as the expression of Notch ligands and target genes in the mammary gland of Holstein heifers in pre- and post-pubertal stages. Notch receptors 1 to 4 were detected by immunohistochemistry in the parenchyma and stroma of the developing gland. The subcellular localization of the four receptors was predominantly cytoplasmic except for NOTCH4, which was mostly nuclear. The membrane and the active intracellular domains of NOTCH paralogues were identified by western blot. NOTCH1 and NOTCH2 active domains increased during pubertal stages while NOTCH3 and NOTCH4 active domains decreased, suggesting strikingly different involvement of NOTCH paralogues in bovine mammary gland development and differentiation. The mRNA expression levels of the target genes HEY1 and HEY2 increased during peri-puberty whereas no variation of HES1 mRNA levels was observed. The mRNA levels of the Notch ligands JAGGED1 and DELTA1 also increased gradually during development. In conclusion, Notch signaling system dynamically varies throughout the development of the mammary gland during puberty pointing to specific time involvement of each component.

Inhibition of Notch signaling attenuates pituitary adenoma growth in Nude mice.

Preclinical and clinical studies support that Notch signaling may play an important oncogenic role in cancer, but there is scarce information for pituitary tumors. We therefore undertook a functional study to evaluate Notch participation in pituitary adenoma growth. Tumors generated in Nude mice by subcutaneous GH3 somatolactotrope cell injection were treated in vivo with DAPT, a γ-secretase inhibitor, thus inactivating Notch signaling. This treatment led to pituitary tumor reduction, lower prolactin and GH tumor content and a decrease in angiogenesis. Furthermore, in silico transcriptomic and epigenomic analyses uncovered several tumor suppressor genes related to Notch signaling in pituitary tissue, namely Btg2, Nr4a1, Men1, Zfp36 and Cnot1. Gene evaluation suggested that Btg2, Nr4a1 and Cnot1 may be possible players in GH3 xenograft growth. Btg2 mRNA expression was lower in GH3 tumors compared to the parental line, and DAPT increased its expression levels in the tumor in parallel with the inhibition of its volume. Cnot1 mRNA levels were also increased in the pituitary xenografts by DAPT treatment. And the Nr4a1 gene was lower in tumors compared to the parental line, though not modified by DAPT. Finally, because DAPT in vivo may also be acting on tumor microenvironment, we determined the direct effect of DAPT on GH3 cells in vitro. We found that DAPT decreases the proliferative, secretory and migration potential of GH3 cells. These results position selective interruption of Notch signaling as a potential therapeutic tool in adjuvant treatments for aggressive or resistant pituitary tumors.

Angiogenesis in pituitary adenomas: human studies and new mutant mouse models.

The role of angiogenesis in pituitary tumor development has been questioned, as pituitary tumors have been usually found to be less vascularized than the normal pituitary tissue. Nevertheless, a significantly higher degree of vasculature has been shown in invasive or macropituitary prolactinomas when compared to noninvasive and microprolactinomas. Many growth factors and their receptors are involved in pituitary tumor development. For example, VEGF, FGF-2, FGFR1, and PTTG, which give a particular vascular phenotype, are modified in human and experimental pituitary adenomas of different histotypes. In particular, vascular endothelial growth factor, VEGF, the central mediator of angiogenesis in endocrine glands, was encountered in experimental and human pituitary tumors at different levels of expression and, in particular, was higher in dopamine agonist resistant prolactinomas. Furthermore, several anti-VEGF techniques lowered tumor burden in human and experimental pituitary adenomas. Therefore, even though the role of angiogenesis in pituitary adenomas is contentious, VEGF, making permeable pituitary endothelia, might contribute to adequate temporal vascular supply and mechanisms other than endothelial cell proliferation. The study of angiogenic factor expression in aggressive prolactinomas with resistance to dopamine agonists will yield important data in the search of therapeutical alternatives.

Gastrointestinal parasite control during prepuberty improves mammary parenchyma development in Holstein heifers.

Parasitism during development impairs normal growth and delays the onset of puberty through altered hormone profiles, including insulin-like growth factor one (IGF-1). As mammary gland development during prepuberty is strongly dependent on IGF-1, we determined if antiparasitic treatment during this stage of growth improved mammary gland development. One group of Holstein heifers was treated monthly, rotationally with antiparasitic drugs from birth to 70 weeks of age, a second group was untreated. Treated heifer calves had between 56% and 65% less EPG counts than untreated ones. Presence of Ostertagia, Cooperia, Haemonchus and Trichostrongylus was demonstrated. Treatment effectively advanced the onset of puberty and increased IGF-1 levels. At 20, 30, 40 and 70 weeks of age biopsies from the mammary gland were taken and histological sections were prepared and stained with hematoxylin-eosin. Pictures were analyzed to compare parenchyma area in relation to total mammary tissue between groups. Mammary samples from treated heifers had higher ratios of parenchyma/total area than untreated ones. As mammary development during prepuberty is crucial for mammary performance during lactation, these results add new evidence to the importance of gastrointestinal parasite control in heifers.

Effect of fat supplementation on leptin, insulin-like growth factor I, growth hormone, and insulin in cattle.

We investigated the effect of fat supplementation on plasma levels of hormones related to metabolism, with special attention to leptin, in cows in early lactation and in feedlot steers. In experiment 1, 34 lactating cows received no fat or else 0.5 or 1.0 kg of partially hydrogenated oil per day in addition to their basal diet from day 20 before the expected calving date to day 70 postpartum. In experiment 2, part of the corn in the basal concentrate was replaced with 0.7 kg of the same oil such that the diets were isocaloric; 18 cows received the fat-substituted diet and 18 a control diet from day 20 before the expected calving date to day 75 postpartum. In experiment 3, calcium salts of fatty acids were added to the basal diet of 14 feedlot steers for 80 d; another 14 steers received a control diet. The basal plasma levels of leptin were higher in the cows than in the steers. Dietary fat supplementation did not affect the leptin levels in the lactating cows but lowered the levels in the feedlot steers despite greater energy intake and body fatness (body weight) in the steers receiving the supplement than in those receiving the control diet. The levels of insulin-like growth factor I and insulin were decreased with dietary fat supplementation in the lactating cows but were unaffected in the steers, suggesting that responses to fat ingestion depend on the physiological state of the animal, including age and sex. Finally, no effects of supplementary fat on the level of growth hormone were demonstrated in any of the models.

Endometritis treatment with a PGF2alpha analog does not improve reproductive performance in a large dairy herd in Argentina.

In Argentina, most dairy cows with endometritis are treated with prostaglandin (PGF(2alpha) or its analogs) and insemination is withheld until there are no signs of endometritis. The objective of the present study was to evaluate if this method of managing endometritis enhances reproductive performance. Three experiments were conducted over 4 years in a large farm in the west of Buenos Aires province. In Experiment 1, half of the cows diagnosed with endometritis (>1.5-fold difference in diameter of uterine horns, as determined by rectal palpation) received standard endometritis management (treatment with tiaprost, a PGF(2alpha) analog, rectal palpation every 20 days, and withholding of AI until endometritis apparently resolved) and the other half was untreated, with AI at the first estrus after the voluntary waiting period. Untreated cows were inseminated and conceived 20 days earlier than treated cows, and the pregnancy rate by Day 90 postpartum was higher in the untreated group. In Experiment 2, cows with endometritis were divided into four groups according to the severity of symptoms; within each group, cows were allocated to treatment or control, as in Experiment 1. Although first service conception rate decreased as endometritis severity increased, reproductive performance in treated versus control cows was similar to that of Experiment 1 (with no interaction due to degree of endometritis). Re-evaluation of the treated cow (to confirm uterine "normality") may have been responsible for the delay in conception in both experiments. The objective of Experiment 3 was to determine the effects of tiaprost treatment on clinically normal postpartum cows (no evidence of endometritis). Tiaprost treatment reduced the interval from calving to conception in multiparous cows, but it delayed conception and reduced the conception rate in primiparous cows. In conclusion, treatment with tiaprost impaired reproductive performance in primiparous cows (in the absence of endometritis). Furthermore, the standard treatment for endometritis (treatment with a prostaglandin analog and withholding insemination until clinical signs abated) impaired reproductive performance and increased costs.

Control hormonal del desarrollo puberal en la rata hembra / Endocrine control of pubertal development in the female rat

La rata hembra resulta un interesante modelo experimental para estudiar el desarrollo del control de las hormonas hipofisarias involucradas en la reproducción. Desde el nacimiento hasta la eclosión puberal transcurren aproximadamente 36 días que pueden ser divididos en 4 etapas: a) neonatal, hasta el día 7 de vida, b) infantil, de 7 a 21, c) juvenil, 21 a 30 días, y d) peripuberal, período que culmina con la primera ovulación. Durante estas etapas los perfiles hormonales son definidos y sujetos a un control característico para cada período. La prolactina está baja hasta el fin del período infantil, momento en que comienza a aumentar gradualmente. Este aumento está relacionado con una maduración de mecanismos liberadores de la prolactina (como el sistema serotoninérgico y el estradiol), en presencia de un aumento del tono dopaminérgico inhibitorio. La prolactina en aumento produce una maduración de los receptores ováricos a LH, y una desensibilización de receptores dopaminérgicos, ambos eventos importantes para la eclosión puberal. La FSH aumenta desde el nacimiento hasta alcanzar el día 12 de vida valores máximos. Luego desciende permaneciendo baja hasta la pubertad. Las causas de este perfil de secreción son múltiples: a los 12 días de edad hay una aumentada sensibilidad de la hipófisis a la LHRH, y una mayor liberación de FSH por serotonina. Por otro lado, frente a una escasa retroalimentación negativa estrogénica y bajos niveles de inhibina, la FSH está bajo control negativo de la...

Control hormonal del desarrollo puberal en la rata hembra / Endocrine control of pubertal development in the female rat

La rata hembra resulta un interesante modelo experimental para estudiar el desarrollo del control de las hormonas hipofisarias involucradas en la reproducción. Desde el nacimiento hasta la eclosión puberal transcurren aproximadamente 36 días que pueden ser divididos en 4 etapas: a) neonatal, hasta el día 7 de vida, b) infantil, de 7 a 21, c) juvenil, 21 a 30 días, y d) peripuberal, período que culmina con la primera ovulación. Durante estas etapas los perfiles hormonales son definidos y sujetos a un control característico para cada período. La prolactina está baja hasta el fin del período infantil, momento en que comienza a aumentar gradualmente. Este aumento está relacionado con una maduración de mecanismos liberadores de la prolactina (como el sistema serotoninérgico y el estradiol), en presencia de un aumento del tono dopaminérgico inhibitorio. La prolactina en aumento produce una maduración de los receptores ováricos a LH, y una desensibilización de receptores dopaminérgicos, ambos eventos importantes para la eclosión puberal. La FSH aumenta desde el nacimiento hasta alcanzar el día 12 de vida valores máximos. Luego desciende permaneciendo baja hasta la pubertad. Las causas de este perfil de secreción son múltiples: a los 12 días de edad hay una aumentada sensibilidad de la hipófisis a la LHRH, y una mayor liberación de FSH por serotonina. Por otro lado, frente a una escasa retroalimentación negativa estrogénica y bajos niveles de inhibina, la FSH está bajo control negativo de la... (AU)