Forte L R, Bylund D B, Zahler W L
Mol Pharmacol. 1983 Jul;24(1):42-7.
Forskolin, a potent activator of adenylate cyclase, has been proposed to activate this enzyme by a direct interaction with the catalytic subunit. To test this hypothesis, we examined the effects of forskolin on sperm cyclic AMP content and sperm adenylate cyclase activity. Forskolin or cholera toxin did not increase cyclic AMP content in either bull or boar sperm, whereas the inhibitors of phosphodiesterase, caffeine and methylisobutylxanthine, significantly increased sperm cyclic AMP content. Forskolin, NaF, and guanylimidodiphosphate did not activate the adenylate cyclase of either sperm membranes or cytosol. When homogenates of rat, guinea pig, or bull testes were centrifuged at 100,000 X g, the supernatant was found to contain a forskolin-stimulated adenylate cyclase. Further centrifugation of this 100,000 X g supernatant fraction at 250,000 X g for 3 hr quantitatively sedimented the forskolin-sensitive enzyme activity. We conclude that forskolin does not activate either the cytosolic or membrane-bound adenylate cyclase of mammalian sperm.
福斯可林是一种有效的腺苷酸环化酶激活剂，有人提出它通过与催化亚基直接相互作用来激活该酶。为了验证这一假设，我们研究了福斯可林对精子环磷酸腺苷（cAMP）含量和精子腺苷酸环化酶活性的影响。福斯可林或霍乱毒素均未增加公牛或公猪精子中的cAMP含量，而磷酸二酯酶抑制剂咖啡因和甲基异丁基黄嘌呤则显著增加了精子中的cAMP含量。福斯可林、氟化钠和鸟苷亚胺二磷酸均未激活精子膜或胞质溶胶中的腺苷酸环化酶。当大鼠、豚鼠或公牛睾丸匀浆在100,000×g下离心时，发现上清液中含有一种受福斯可林刺激的腺苷酸环化酶。将该100,000×g上清液部分在250,000×g下进一步离心3小时，可定量沉淀对福斯可林敏感的酶活性。我们得出结论，福斯可林不会激活哺乳动物精子的胞质溶胶或膜结合型腺苷酸环化酶。
