Diabetogenic effects of chronic oral cadmium adminstration to neonatal rats.

1 Chronic exposure of neonatal rats to oral cadmium (Cd) (0.1 and 1.0 micrograms/g daily for 45 days) disturbed glucose homeostasis, as reflected by hyperglycaemia, reduced liver glycogen and enhanced gluconeogenic potential of hepatic tissue. 2 This Cd-exposure regimen also increased hepatic cyclic adenosine 3',5'-monophosphate (cyclic AMP) which was accompanied by enhancement of basal, adrenaline and glucagon-stimulated form(s) of adenylate cyclase. 3 In order to assess the responsiveness of pancreatic beta cells to glucose, islets isolated from control as well as Cd-exposed animals were incubated in vitro and their rate of insulin secretion determined. In the presence of glucose 0.5 mg/ml, there was no significant difference in the rate of insulin release. However, at higher glucose concentrations (1.5 and 3.0 mg/ml), the islets from Cd-exposed rats released significantly less insulin than those of control animals. 4 The results are discussed in relation to the possible mechanism of the diabetogenic effect of Cd.