The effects of testosterone on rooster gonad maturation and regeneration

• Main Authors: Yu-Ting Chen, 陳育婷
• Other Authors: 鄭旭辰
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/46961825129953860095

碩士 === 國立中興大學 === 生命科學院碩士在職專班 === 99 === Many clinical studies show that testosterone abuse caused testis atrophy; androgen receptor inhibits the cutaneous wound healing. It has also been demonstrated that testosterone can promote angiogenesis, which provides nutrients more efficiently to the growing tissue. These results showed contradicting roles of testoasterone in tissue regeneration. Our laboratory has established the rooster testis as a model system for analyzing the molecular mechanisms of tissue regeneration. To resolve above mentioned dilemma, I would like to explore the impact of testosterone on the testis regeneration. In male mammals, the hypothalamus increases its secretion of gonadotropin releasing hormone （GnRH）which in turn stimulates the release of luteinizing hormone and follicle stimulating hormone. This leads to the production of testosterone and the sexual development associated with puberty: growth spurt, increased libido, increased erectile function, acne, increased body hair, increased muscle mass, deepening of the voice and spermatogenesis. In male, testosterone is the major hormone that affects GnRH secretion, which in turn inhibits gonadotropin secretion via negative feedback both at the hypotha-lamic and pituitary level. The experiments started with autologous transplantation of 1μl of testicular tissue to the subcutaneous space followed by weekly injection of testosterone or vehicle solution. Weekly changes of plasma testosterone level and regenerative tissue size were carefully monitored, and biopsy of regenerating testis was performed on regularly. I found exogenous testosterone made the regeneration testis grew larger in size and better ability of spermatogenesis, though the serum testosterone level remained low for both regenerative groups with or without testosterone administration. Since the endogenous testosterone is produced by testes and adrenal, further studies on the regulation of testosterone secretion by adrenal may help us to understand the low plasma testosterone post castration surgery.