Abstract
During the initial stages of insect flight, adipokinetic hormone (AKH) is released from secretory cells in the corpora cardiaca and causes the release of specific diglycerides, which are used by the flight muscles as a source of energy. Recently, AKH has been demonstrated by immunohistochemical technique to be present in rat pancreatic tissue. In the present study, using a rat pancreatic perfusion system, the possible involvement of AKH in endocrine pancreatic function was assessed. In basal conditions, 10nM AKH induced about a 50% decrease in glucagon levels although there was no apparent effect on insulin secretion. Using 10mM arginine HCl and 18.5mM tolbutamide as secretagogues, the modulatory effects of AKH on insulin and glucagon secretion were examined. Arginine-induced insulin and glucagon secretion was significantly suppressed by the simultaneous administration of 1nM (p<0.05) or 10nM (p<0.05) AKH, while the tolbutamide-induced insulin secretion was significantly suppressed (p<0.05) without any significant change in glucagon secretion. These results indicate that a modulatory effect of AKH may exist in the endocrine pancreas and suggest that AKH may have some physiological role in the mammalian pancreas.
