The Mechanism of Hypoglycemia Due to Semistarvation in the Rat

Abstract

A quantity of diet providing 50% of the energy and protein requirement was fed to 4 week old rats. After 3 weeks, the amount of food was reduced to 25% and resulted in hypoglycemia in most of the rats within 4 to 7 days. The rats were divided into three groups: 1) normal controls; 2) malnourished, exhibiting blood sugar levels more than 40 mg/100 ml; 3) malnourished with blood sugar concentration less than 40 mg/100ml. The plasma concentrations of energy providing substrates: free fatty acids, glycerol, pyruvic acid, lactic acid and alanine were significantly lower in the hypoglycemic group than in the other two groups, while the first two groups displayed no significant differences. Plasma insulin concentrations were reduced in the undernourished groups and the lowest levels were found in the hypoglycemic rats. The plasma corticosterone concentration was significantly greater in group 2 but only slightly higher in group 3 than in the controls. Blood glucose concentration did not increase after intravenous glucagon in group 3, but the response was restored 4 hours after glucose administration. Blood glucose did not increase after alanine infusion in group 3 and increased only moderately in group 2. There was a normal increase after glycerol infusion in both malnourished groups. It was concluded that in semistarvation, fatal hypoglycemia is due to the depletion of fat stores accompanied by impaired gluconeogenesis from alanine.