Asakawa T, Ruiz J, Ho R J
Proc Natl Acad Sci U S A. 1978 Jun;75(6):2684-8. doi: 10.1073/pnas.75.6.2684.
The effects of epinephrine (as low as 0.1 muM) on guanosine 3':5'-cyclic monophosphate (cGMP) and adenosine 3':5'-cyclic monophosphate (cAMP) in isolated fat cells were examined. Epinephrine increased both cGMP and cAMP levels, with the elevation of cAMP preceding the rise of cGMP. Maximal elevation was obtained with 1 muM epinephrine for each nucleotide. The increase in content of cGMP and cAMP due to epinephrine was completely blocked by a beta-adrenergic antagonist (5 muM propranolol). Phentolamine (10-100 muM), an alpha-adrenergic antagonist, enhanced the response to epinephrine resulting in elevation of cAMP levels, whereas a high concentration (100 muM) of phentolamine suppressed the elevation of cGMP. The ability of epinephrine to increase cGMP and cAMP levels was markedly diminished by "feedback regulator" partially purified from the incubation mixtures of isolated fat cells exposed to epinephrine [Ho, R.J. & Sutherland, E. W. (1971) J. Biol. Chem. 246, 6822-6827], whereas an increase in cGMP, but not cAMP, levels was observed in isolated fat cells incubated with "feedback regulator" alone (without epinephrine). These observations suggest the possibility that the epinephrine-induced elevation of cGMP levels in isolated fat cells might be mediated by an increase in formation of intracellular "feedback regulator" due to an elevation of cAMP by epinephrine.
研究了肾上腺素（低至0.1μM）对分离的脂肪细胞中鸟苷3':5'-环磷酸（cGMP）和腺苷3':5'-环磷酸（cAMP）的影响。肾上腺素使cGMP和cAMP水平均升高，cAMP的升高先于cGMP的升高。每种核苷酸在1μM肾上腺素作用下达到最大升高。肾上腺素引起的cGMP和cAMP含量增加被β-肾上腺素能拮抗剂（5μM普萘洛尔）完全阻断。α-肾上腺素能拮抗剂酚妥拉明（10 - 100μM）增强了对肾上腺素的反应，导致cAMP水平升高，而高浓度（100μM）的酚妥拉明抑制了cGMP的升高。从暴露于肾上腺素的分离脂肪细胞孵育混合物中部分纯化得到的“反馈调节剂”显著降低了肾上腺素升高cGMP和cAMP水平的能力[Ho, R.J. & Sutherland, E. W. (1971) J. Biol. Chem. 246, 6822 - 6827]，而单独用“反馈调节剂”（无肾上腺素）孵育的分离脂肪细胞中观察到cGMP水平升高，但cAMP水平未升高。这些观察结果提示，肾上腺素诱导的分离脂肪细胞中cGMP水平升高可能是由于肾上腺素使cAMP升高导致细胞内“反馈调节剂”形成增加所介导的。
