CHEMICAL STUDIES ON THE CONTRACEPTIVE ACTION OF GOSSYPOL

棉酚是一种从棉花植物中提取的多酚化合物， 对人类和实验动物产生抗精子作用。它坚持住了 作为一种男性口服避孕药，前景看好，但几乎没有 从分子水平上了解其对睾丸的作用机制。 在这项提议中要检验的假设是棉酚抑制 优先与乳酸酶相互作用的精子发生 脱氢酶-X(LDH-X)在特定的生精细胞，即精子细胞， 而这种抑制的结果是能量的损害 最终导致细胞死亡。这项研究将在 非人灵长类动物模型，食蟹猴(束支猴)，其中 棉酚的抗精子生成和临床作用是已知的。我们的 方法将是(1)更确凿地证明，使用LDH同工酶 从猴子的精子、心脏和肝脏中提纯棉酚优先 抑制LDH-X，进而确定其抑制机制。(2) 然后我们将确定棉酚是否抑制了能量代谢 离体猴粗线期精母细胞和精细胞的体外培养 这与细胞内LDH-X的相对含量有关。(3)最后， 我们将给食蟹猴口服棉酚，然后 在分离精母细胞和精子细胞并孵育后测定 在体外，口服给药的生化后果是否是 对完整动物精子细胞中LDH-X的抑制作用。

Gossypol is a polyphenolic compound derived from the cotton plant which exerts antispermatogenic effects in man and experimental animals. It holds considerable promise as an oral male contraceptive in man yet little is known about its mechanism of action on the testis at the molecular level. The hypothesis to be tested in this proposal is that gossypol inhibits spermatogenesis by preferentially interacting with the enzyme lactic dehydrogenase-X (LDH-X) in specific spermatogenic cells, ie, spermatids, and that the consequence of this inhibition is impairment of energy production and eventual cell death. The study will be carried out with a nonhuman primate model, the cynomolgus monkey (M. fascicularis) in which the antispermatogenic and clinical effects of gossypol are known. Our approach will be (1) To demonstrate more conclusively, using LDH isozymes purified from monkey sperm, heart, and liver that gossypol preferentially inhibits LDH-X and then to determine the mechanism of this inhibition. (2) We will then determine if energy metabolism is inhibited by gossypol in vitro in isolated monkey pachytene speratocytes and spermatids in a manner which correlates with the relative amount of cellular LDH-X. (3) Finally, we will administer gossypol orally to cynomolgus monkeys and then determine, after isolation of spermatocytes and spermatids and incubation in vitro, whether the biochemical consequence of oral administration is the inhibition of LDH-X in spermatids in the intact animal.