Tsang B K, Thakur A N, Singhal R L
Can J Comp Med. 1979 Jan;43(1):59-67.
Endogenous cyclic AMP levels and the activities of adenylate cyclase, cyclic AMP-dependent and independent protein kinases were examined in testes of mature rats bilaterally vasectomized for one, three and seven months. Although no significant alteration in testicular cyclic AMP was detected one month following vasectomy, marked decreases (by 55% and 32%, respectively) were seen three and seven months postvasectomy. Likewise, vasectomy also resulted in a significant decrease (by 25%) in the activity of testicular adenylate cyclase three and seven months after vasectomy. Although soluble cyclic AMP-dependent protein kinase activity remained unaffected three months postvasectomy, the activity of the cyclic nucleotide-dependent enzyme was significantly increased (by 21%) when compared to the sham-operated controls. Furthermore, while the protein kinase ratio (--cyclic AMP/+cyclic AMP) was decreased in animals vasectomized for three months, the ability of the enzyme to bind (3H) cyclic AMP in vitro was significantly enhanced (18%). Rats vasectomized for seven months showed similar biochemical alterations but the effects of this procedure were more pronounced. Moreover, while short-term vasectomy increased the responsiveness of seminiferous tubular adenylate cyclase to in vitro stimulation by follicle stimulating hormone, the activity of the enzyme was also increased (by 100%) in the presence of luteinizing hormone in vasectomized rats. These data raise the possibility that changes in testicular function seen following vasectomy may be related to the alterations in cyclic AMP metabolism as well as in the sensitivity of testicular adenylate cyclase to regulation by gonadotropins.
对双侧输精管结扎1个月、3个月和7个月的成年大鼠睾丸内源性环磷酸腺苷（cAMP）水平以及腺苷酸环化酶、环磷酸腺苷依赖性和非依赖性蛋白激酶的活性进行了检测。输精管结扎1个月后，睾丸cAMP未检测到显著变化，但输精管结扎3个月和7个月后，cAMP显著降低（分别降低55%和32%）。同样，输精管结扎3个月和7个月后，睾丸腺苷酸环化酶的活性也显著降低（降低25%）。虽然输精管结扎3个月后可溶性环磷酸腺苷依赖性蛋白激酶活性未受影响，但与假手术对照组相比，该环核苷酸依赖性酶的活性显著增加（增加21%）。此外，输精管结扎3个月的动物中，蛋白激酶比率（-环磷酸腺苷/+环磷酸腺苷）降低，但该酶在体外结合（3H）环磷酸腺苷的能力显著增强（增强18%）。输精管结扎7个月的大鼠表现出类似的生化改变，但这种手术的影响更为明显。此外，短期输精管结扎增加了生精小管腺苷酸环化酶对促卵泡激素体外刺激的反应性，在输精管结扎大鼠中，促黄体生成素存在时该酶的活性也增加了（增加100%）。这些数据提示，输精管结扎后睾丸功能的变化可能与环磷酸腺苷代谢的改变以及睾丸腺苷酸环化酶对促性腺激素调节的敏感性改变有关。
