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]

O objetivo deste estudo foi avaliar os efeitos do FSH pituitário (pFSH) ou recombinante (rFSH) sobre a sobrevivência e o crescimento de folículos pré-antrais caprinos. O tecido ovariano foi cultivado in vitro por um ou sete dias em Meio Essencial Mínimo (MEM) sozinho, ou contendo 10, 50, 100 e 1000 ng/ml de pFSH ou rFSH. O grupo controle (não cultivado) e aqueles cultivados foram processados para análises histológica e ultra-estrutural. Além disso, os diâmetros folicular e oocitário foram avaliados. Após sete dias de cultivo, apenas 50 ng/ml de rFSH manteve o percentual de folículos normais semelhante ao controle. Além disso, 10 ng/ml de pFSH e todas as concentrações de rFSH promoveram ativação de folículos primordiais. A presença de 50 ng/ml de rFSH promoveu o maior diâmetro folicular após sete dias de cultivo. Em conclusão, 50 ng/ml de rFSH manteve a integridade de folículos pré-antrais caprinos e promoveu a ativação e o crescimento dos folículos cultivados.

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.