Some Effects of Prolonged Undernutrition on Carbohydrate Metabolism in Rats

Abstract

A) Rats fed 10 gm of ground Rockland diet/day for 4–6 weeks and then fasted for 24 hours showed an enhanced insulin sensitivity as compared with ad libitum-fed rats that were fasted for the same length of time. The fasting blood sugar and liver glycogen concentrations were significantly higher in underfed animals. B) Underfed rats were fasted 24 hours, then fed 5 gm/ 100 gm body weight and tested 8 hours later. These rats exhibited a) no greater insulin sensitivity, b) lower blood sugar levels and c) a smaller rise in liver glycogen concentration than similarly treated ad libitum-fed animals. Intestinal absorption of glucose was not diminished in the undernourished rats. C) Cortisone treatment (0.5 mg/100 gm body wt/day for 5 days) abolished the insulin sensitivity of underfed rats without altering the hepatic glycogen concentration. Somatotrophin (0.5 mg Armour standard equivalent/100 gm body wt/day for 5 days) did not improve their insulin tolerance. After functional evisceration, the blood sugar fall (if expressed as percentage of the initial level) was significantly slower in underfed than in ad libitum-fed rats. However, the decline of the blood sugar level appeared to be more markedly enhanced by insulin in the underfed animals.