Schauder P, McIntosh C, Schindler B, Panten U, Frerichs H
Mol Cell Endocrinol. 1978 Jun;11(1):51-61. doi: 10.1016/0303-7207(78)90032-1.
The insulinotropic effects of alpha-ketoisocaproic acid and glucose reveal many common characteristics in vivo and in vitro. They qualify as initiators of insulin release, their action is amplified by potentiators of insulin release, and they have a similar potency at equimolar concentrations. The dynamics of insulin release evoked by alpha-ketoisocaproic acid and glucose are similar. Epinephrine completely inhibits the insulinotropic effect of glucose and alpha-ketoisocaproic acid. Mannoheptulose exhibits a complete, immediate and reversible blockade of glucose-induced insulin release. In contrast, inhibition of alpha-ketoisocaproic acid-induced insulin release occurs after a lag period and is not reversed by removal of the inhibitor. alpha-ketoisocaproic acid, at equimolar concentrations, is several-fold more effective than glucose in elevating cAMP content in islet. alpha ketoisocaproic acid and glucose are about equally effective in stimulating somatostatin release from isolated rat pancreatic islets. This stimulation is inhibited by epinephrine. Mannoheptulose inhibits only somatostatin release induced by glucose but not by alpha-ketoisocaproic acid. It suggested that the insulinotropic characteristics of glucose and alpha-ketoisocaproic acid reveal many common features, while their mode of action appears to be different.
α-酮异己酸和葡萄糖的促胰岛素作用在体内和体外显示出许多共同特征。它们可作为胰岛素释放的启动剂，其作用可被胰岛素释放增强剂放大，并且在等摩尔浓度下具有相似的效力。由α-酮异己酸和葡萄糖诱发的胰岛素释放动力学相似。肾上腺素完全抑制葡萄糖和α-酮异己酸的促胰岛素作用。甘露庚酮糖对葡萄糖诱导的胰岛素释放表现出完全、即时且可逆的阻断作用。相比之下，α-酮异己酸诱导的胰岛素释放抑制在一段延迟期后发生，且不会因去除抑制剂而逆转。在等摩尔浓度下，α-酮异己酸在提高胰岛中cAMP含量方面比葡萄糖有效几倍。α-酮异己酸和葡萄糖在刺激离体大鼠胰岛释放生长抑素方面效果大致相同。这种刺激被肾上腺素抑制。甘露庚酮糖仅抑制葡萄糖诱导的生长抑素释放，而不抑制α-酮异己酸诱导的生长抑素释放。这表明葡萄糖和α-酮异己酸的促胰岛素特征显示出许多共同特征，而它们的作用方式似乎不同。
