Inhibin secretion in the XXXX ( @entity329 ) testis during active and inactive states of spermatogenesis induced by the restriction of photoperiod.

@entity251 @entity851 @entity72232 @entity25086 @entity329
Gonadal function in the male @entity329 ( @entity329 ) was investigated during exposure to a @entity851 . Within 3 weeks of exposure to the @entity851 , FSH and @entity251 in the plasma significantly decreased, and subsequently immunoreactive (ir)-inhibin significantly decreased. Testicular contents of ir-inhibin and @entity251 , and pituitary contents of LH and FSH also significantly decreased by 3 weeks with regression of weight of testes, epididymis and seminal vesicles and sperm head count. Circulating LH varied but not significantly. Thereafter, all reproductive parameters and secretion of LH, FSH, ir-inhibin and @entity251 gradually recovered after 17 weeks of exposure even though animals continued to be subjected to the @entity851 . Plasma concentrations of @entity25086 and inhibin pro-alphaC were detectable and were significantly decreased after 15 weeks of exposure to the short photoperiod, but their levels were still detectable. Immunopositive reaction of @entity72232 and betaB subunits was found in Sertoli cells and Leydig cells in the regressed testes of animals subjected to short photoperiod as was also seen in animals before exposure to the short photoperiod. Although the spermatogenic cycle was suppressed like prepubertal animals, the present study showed that the testicular recovery, so-called refractoriness, is functionally different from the developing stage of immature animals, especially with regard to inhibin secretion. The present results showed that changes in FSH preceded changes in inhibin during the regression and recovery phases, indicating that FSH is a major regulatory factor of inhibin secretion in male @entity329 . The present study also demonstrated that regressed testes still secrete a small amount of bioactive inhibin during exposure to a short-photoperiod condition.
