FASTING GLUCOSE-HOMEOSTASIS IN THE ADAPTATION TO CHRONIC NUTRITIONAL DEPRIVATION IN RATS

The hormonal basis for the metabolic paradox of relative hypoglycemia despite insulinopenia and insulin resistance in chronic nutritional de privation was studied in weanling rats restricted to 60% of ad libitum intake over 8 wk (n = 12 each). Lower insulin and glucagon levels wer e observed in both peripheral and portal blood (P = 0.0016) in the mal nourished rats on multivariate analysis of variance, indicating decrea sed islet secretion. Peripheral and portal hormone levels were proport ionately similar, indicating that hepatic extraction was not altered. Despite relative hypoglycemia, glucose turnover rate, total glucose ma ss, and volume of distribution of glucose were not altered. This indic ates that the sum total of the effects of malnutrition on the various hormonal influences controlling glucose turnover had resulted in the e stablishment of a new dynamic equilibrium associated with lower plasma glucose levels. It is concluded that fasting glucose levels are susta ined at a lower level in chronic malnutrition by an adaptive process t hat includes insulin resistance and insulinopenia, counterbalanced not only by glucagon resistance, as shown earlier, but also by decreased glucagon secretion.