1986 Volume 150 Issue 1 Pages 17-24
ISHIZUKA, J., TOYOTA, T., ONO, T., SASAKI, M., YANAIHARA, C. and YANAIHARA, N. Inhibitory Effects of Rimorphin and Dynorphin on Insulin Secretion from the Isolated, Perfused Rat Pancreas. Tohoku J. exp. Med., 1986, 150(1), 17-24-In order to settle the question about whether or not opioid peptides stimulate or inhibit insulin secretion, we studied effects of rimorphin and dynorphin, two members of the preproenkephalin B group, on glucose-induced insulin secretion in the isolated, perfused rat pancreas. These peptides (3.95×10-8 M), like morphine (3.95×10-8M), significantly inhibited the glucose-induced insulin secretion. The inhibitory effect of rimorphin was attenuated by naloxone (1.2×10-6M) and phentolamine (10-6M), suggesting an involvement of adrenergic alpha receptors in the inhibition of glucose-induced insulin secretion mediated through specific opiate receptors. Rimorphin also inhibited glucose-induced insulin secretion even in the cysteamine-treated rat pancreas from which somatostatin had been depleted. Thus, somatostatin does not appear to play a major regulatory role in the insulin secretion in the pancreas.
