Metabolic and hormonal effects of exercise in the severely streptozotocin-diabetic rat

Abstract

Metabolic and hormonal changes during muscular exercise were studied in streptozotocin (65 mg/kg) - diabetic rats. The untreated, non-fasted animals ran in a rotating cage for 30 min, and blood, liver and pancreatic specimens were taken before, immediately after and/or two hrs after exercise. The slight pre-exercise acidosis of the diabetic rats changed during exercise to a marked acidosis due to a rise in blood lactate. High blood glucose fell in 33 out of 54 animals, while hepatic glycogen was low and unchanged. A marked increase in circulating glycerol was found, whereas plasma free fatty acids (FFA) decreased and the fall of FFA was glucose "sparing". In animals, in which blood glucose decreased, plasma immunoreactive insulin (IRI) rose significantly and the rise correlated with the fall in blood glucose and with the intensity of work. Exercise did not affect the low pancreatic content of IRI. The results add weight to the suggestion that in severe, acute diabetes muscular work can mobilize IRI, perhaps of extrapancreatic origin, which helps to explain the decrease in circulating glucose. © 1974 Springer-Verlag.