Weatherhead B, Logan A
J Endocrinol. 1981 Jul;90(1):89-96. doi: 10.1677/joe.0.0900089.
In short-term (48 h) cultures of hair follicles alpha-melanocyte-stimulating hormone (alpha-MSH) and cyclic AMP stimulated melanogenesis through an increase in tyrosinase activity. In contrast cyclic GMP mimicked the effects of melatonin by inhibiting melanin production without causing a concomitant decrease in tyrosinase activity. Both cyclic GMP and melatonin blocked the stimulatory effects of cyclic AMP and alpha-MSH on melanin production but they left the increased levels of tyrosinase activity unaffected. Phosphodiesterase inhibitors (3-isobutyl-1--methylxanthine and papaverine) simultaneously stimulated tyrosinase activity and inhibited melanin production, presumably by allowing endogenous cyclic AMP and cyclic GMP to accumulate intracellularly. It is suggested that whereas MSH stimulates melanogenesis through a cyclic AMP-dependent mechanism there must also be an inhibitory cyclic GMP-dependent mechanism, perhaps activated by melatonin, which operates at some post-tyrosinase step in the melanin biosynthetic pathway.
在毛囊的短期（48小时）培养中，α-黑素细胞刺激素（α-MSH）和环磷酸腺苷（cAMP）通过增加酪氨酸酶活性来刺激黑素生成。相比之下，环磷酸鸟苷（cGMP）通过抑制黑色素生成来模拟褪黑素的作用，而不会同时导致酪氨酸酶活性下降。cGMP和褪黑素都阻断了cAMP和α-MSH对黑色素生成的刺激作用，但它们并未影响酪氨酸酶活性的升高水平。磷酸二酯酶抑制剂（3-异丁基-1-甲基黄嘌呤和罂粟碱）同时刺激酪氨酸酶活性并抑制黑色素生成，推测这是通过使内源性cAMP和cGMP在细胞内积累来实现的。有人提出，虽然MSH通过依赖cAMP的机制刺激黑素生成，但必然也存在一种依赖cGMP的抑制机制，可能由褪黑素激活，该机制在黑色素生物合成途径中酪氨酸酶之后的某个步骤起作用。
