Lipson L G, Bush M J, Tietjen G E, Yoon A
Acta Endocrinol (Copenh). 1981 Feb;96(2):222-6. doi: 10.1530/acta.0.0960222.
In attempting to understand the causes of the hyperglycaemia observed in aging populations and to determine the mechanism(s) for the diminished in vitro insulin release from islets of Langerhans of older rats, the adenylate cyclase-cyclic AMP system was studied in isolated islets from 12 month old and 2 1/2 month old (control) male rats to determine its role in this altered insulin secretion. Islets of Langerhans were isolated by collagenase digestion and then either incubated in the presence of low or high concentrations of glucose for studies of insulin release or were sonicated and assayed for determinations of activities of adenylate cyclase and phosphodiesterase. Insulin release was identical from islets of 12 month old and 2 1/2 month old rats to 2.8 mM D-glucose, while in the presence of 16.7 mM D-glucose, insulin release was decreased by 33% (P less than 0.02) from islets of the older animals. Adenylate cyclase activity was diminished by 60% (P less than 0.005) from the 12 month old rats as compared with islets from the 2 1/2 month old controls, while low Km phosphodiesterase activity was similar in islets from both groups of animals. From these studies it appears that the adenylate cyclase-cyclic AMP system may play a role in the altered insulin release from islets of aging rats.
为了试图理解在老龄人群中观察到的高血糖症的病因，并确定老年大鼠胰岛体外胰岛素释放减少的机制，对12月龄和2个半月龄（对照）雄性大鼠分离的胰岛中的腺苷酸环化酶 - 环磷酸腺苷系统进行了研究，以确定其在这种改变的胰岛素分泌中的作用。通过胶原酶消化分离胰岛，然后在低浓度或高浓度葡萄糖存在下孵育以研究胰岛素释放，或者超声处理并测定腺苷酸环化酶和磷酸二酯酶的活性。12月龄和2个半月龄大鼠的胰岛对2.8 mM D-葡萄糖的胰岛素释放相同，而在16.7 mM D-葡萄糖存在下，老年动物胰岛的胰岛素释放减少了33%（P < 0.02）。与2个半月龄对照的胰岛相比，12月龄大鼠的胰岛腺苷酸环化酶活性降低了60%（P < 0.005），而两组动物胰岛中的低Km磷酸二酯酶活性相似。从这些研究看来，腺苷酸环化酶 - 环磷酸腺苷系统可能在老年大鼠胰岛改变的胰岛素释放中起作用。
