A different pattern of insulin release in the perifused islets of the rabbit

Summary The role of the microtubular-microfilament system in the glucose mediated insulin secretory response has been investigated though a functional comparative study of perifused endocrine islets isolated from the pancreases of rats and rabbits. While microtubules are the main contractile organelles in the rat islets, microfilaments predominate in the beta cells of the rabbit. Rat islets displayed a biphasic response to glucose stimulated insulin secretion while in the rabbit the response was characterized by a multiphasic pattern. The short duration phases of glucose mediated insulin secretion in the rabbit resemble the “first phase” shown in the rat islets. On the basis of these findings it is suggested that the microtubules may be mainly involved with the mechanisms of sustained insulin released during glucose stimulation.