Male Japanese black bears (Ursus thibetanus japonicus) have an explicit reproductive cycle. The objective of this study was to clarify the variation of plasma testosterone, FSH, inhibin, LH levels and testicular gonadotropin receptor mRNA expression of male bears associated with their testicular activity. Notably, this study investigated peripheral FSH concentration and localization of gonadotropin receptor mRNAs for the first time in male bears. Blood and testicular tissue samples were taken from captive, mature, male Japanese black bears during testicular active, regressive and recrudescent phases. Plasma hormone concentrations were measured by immunoassays, and gonadotropin receptor mRNA expression in the testis was investigated by in situ hybridization technique and also by real-time PCR. There were significant variations in plasma testosterone and inhibin concentrations. Changes in FSH concentration preceded these hormones with a similar tendency. Hormones started to increase during denning, and achieved the highest values at the end of the recrudescent phase for FSH and in the active phase for testosterone and inhibin. These changes in hormone concentrations were accompanied by testicular growth. In situ hybridization analysis revealed that FSH and LH receptor mRNA was possibly expressed in Sertoli cells and Leydig cells, respectively, as they are in other mammals. However, neither plasma LH concentration nor testicular gonadotropin receptor mRNA expression level varied significantly among the sampling months. These results suggest that FSH, inhibin and testosterone have roles in testicular activity in male bears. This study provides important endocrine information for comprehending seasonal reproductivity in male Japanese black bears.

Objective: This study was conducted to investigate the effects of estradiol benzoate injection to intact and castrated male rabbits on LH, FSH, testosterone and prostate tissue. Materials and methods: A total of 72 mature male rabbits were used in this study. The rabbits were randomly divided into two groups (36 intact and 36 castrated) and each group was further divided into four sub-groups. The rabbits of each subgroup were injected estradiol benzoate dosed at 0, 40, 80 and 120 and micro;gm/rabbit, through intramuscular (IM) route, on each alternative day over a period of 30 days. The levels of LH, FSH, and testosterone were measured in serum samples. Prostate tissue samples were taken from each sub-groups, histological examination was done. Results: The mean serum levels of LH and FSH were not affected by injection of estradiol benzoate in all intact and castrated rabbits sub-groups (P>0.05). However, the results of testosterone levels were showed insignificant increase in all intact and castrated male rabbits sub-groups, except the intact male rabbit sub-group that received estradiol benzoate at 120 and micro;g/rabbit (P<0.05). Furthermore, the effects of estradiol benzoate in prostate tissues were ranged from hyperplasia with dysplasia or dysplasia only in intact male rabbits; hyperplasia was represented by papillary projection in castrated male rabbits. Conclusion: The present study revealed no difference in the serum levels of LH, FSH in intact or castrated male rabbits, however, testosterone hormone did not show any change except in sub-group of intact male rabbits that was injected dosed at 120 and micro;g estradiol benzoate. The effect of estradiol benzoate on prostate tissue was found to be induce hyperplasia in both intact and castrated males rabbits. [J Adv Vet Anim Res 2016; 3(4.000): 420-424]

The aim of the experiment was to determine whether charcoal-treated bovine follicular fluid (bFF) removed from visible (&lt; 22 mm) follicles altered the secretion of follicle-stimulating hormone (FSH) in intact and ovariectomized prepubertal heifers. After a 10-ml injection of bFF given at three consecutive 8-h intervals, secretion of FSH was depressed in approximately 44% of the ovariectomized heifers but there was no effect in intact heifers. When the bFF treatment ceased, there were no rebound effects on FSH concentrations above that of controls pretreatment levels. These results suggest that proteins from bFF act at the pituitary level to inhibit FSH secretion and, differently of the intact, the ovariectomized heifer is an adequate model to put this effect in evidence, particularly when the bFF have low FSH suppressing activity. | O presente trabalho objetivou determinar o efeito do líquido folicular bovino tratado com carvão ativado (LFb) na secreção do hormônio folículo estimulante (FSH) de novilhas pré-púberes ovariectomizadas ou intatas. A aplicação de LFb (quatro injeções de 10 ml com intervalo de 8 horas) provocou uma queda de aproximadamente 44% na concentração plasmática de FSH nas novilhas ovariectomizadas, mas não teve efeito nas novilhas intatas. Não foi observada hipersecreção de FSH após o término da aplicação do LFb. Esses resultados sugerem que proteínas presentes no LFb atuam ao nível hipofisiário para inibir a secreção de FSH e, diferentemente das intatas, as novilhas ovariectomizadas constituem um modelo adequado para evidenciar esse efeito, particularmente quando o LFb possui reduzida atividade supressora do FSH.

Simmental cows from northwest of the Paraná State and south of Mato Grosso do Sul, were used. A superovulation of donors’ cows was induced with FSH, and for embryos inovulation in recipient cows, the surgical method was used. Hundred and three recovered ova were employed and 749 recipients cows were utilized. From 1014 recovered embryos, 81.8% were transferred and the remaining embryos were frozen or rejected. The number of embryos recovered per cow averaged 9.8 ± 6.6 and transferred 8.0, resulting in 3.8 pregnancies per recovery. There were 4.8% of recoveries without embryos and 1.9 % of unfertilized ova. Middle and larger Corpora lutea in the recipients cows, had a significant influence on the pregnancy rate in relation to the smaller (p&lt;0.05) and 64.0% of recipients cows had the ovulation on the right ovary. The pregnancy rate relative to the estrus synchronization between donors and receptors cows was higher between days + 2 and -2 (p&gt;;0.05) (the + sign indicates that the oestrus in the recipient started after that in the donor and vice versa), being very poor after this time. Embryos classified as very good and good and inovulated, influenced significantly the pregnancy rate. The general pregnancy rate was 47.0%. | No experimento foram utilizadas vacas da raça Simental procedentes de fazendas das Regiões Noroeste do Estado do Paraná e Sul do Mato Grosso do Sul, administrando-se o hormônio folículo estimulante (FSH) para a superovulação e utilizando-se o método cirúrgico para a inovulação dos embriões nas receptoras. No total foram efetuadas 103 colheitas e utilizadas 749 vacas receptoras. Foram colhidos 1.014 embriões sendo 81,8% destes transplantados e os restantes congelados ou rejeitados. Colheram-se em média 9,8 embriões por doadora sendo 8,0 transplantados, proporcionando 3,8 animais prenhes por colheita. Ocorreram 4,8% de colheitas sem embrião e 1,9% de óvulos não-fertilizados. Relativamente ao tamanho do corpo lúteo (CL) palpado nas vacas receptoras, os dados demonstraram que os Corpora lutea de médio e maior tamanho tiveram significativa influência sobre a taxa de prenhez em relação aos de menor tamanho (p&lt;0,05) e 64,0% das receptoras ovularam no ovário do lado direito. A taxa de prenhez em relação à sincronia de estro entre doadoras e receptoras foi mais elevada entre os dias mais 2 e menos 2 (p&gt;;0,05) (o mais significa que o estro nas receptoras ocorreu após o da doadora e vice-versa), sendo muito baixa além destes limites. Os embriões classificados como ótimos e bons e inovulados influíram significativamente sobre o percentual de prenhez, e o total geral da taxa de gestação foi de 47,0%.