French R R, York D A
Diabetologia. 1984 Jun;26(6):466-72. doi: 10.1007/BF00262223.
Adenylate cyclase activity was determined using a purified plasma membrane fraction prepared from isolated adipocytes by a Percoll gradient centrifugation procedure. The activation of adenylate cyclase by isoprenaline was reduced by approximately 50% in membranes from obese mice, although no reduction in the sensitivity of the response was apparent. Basal and fluoride- and 5'-guanylyl-imidodiphosphate-stimulated activities were similar in both groups. However, two defects in the obese system were identified which suggested that an alteration in the properties of the regulatory protein may account for the impaired hormonal activation. The specific binding of 3H-dihydroalprenolol to membranes from obese animals also was decreased, suggesting a reduction in the number of beta-adrenergic receptors.
采用通过Percoll梯度离心法从分离的脂肪细胞制备的纯化质膜组分来测定腺苷酸环化酶活性。尽管反应敏感性没有明显降低，但在肥胖小鼠的膜中，异丙肾上腺素对腺苷酸环化酶的激活作用降低了约50%。两组的基础活性以及氟化物和5'-鸟苷酰亚胺二磷酸刺激的活性相似。然而，在肥胖系统中发现了两个缺陷，这表明调节蛋白性质的改变可能是激素激活受损的原因。肥胖动物膜上3H-二氢阿普洛尔的特异性结合也减少，表明β-肾上腺素能受体数量减少。
