Glycogen in Adipose Tissue after Insulin Injection

Abstract

WHEN insulin is injected into a normal rat of about 100 gm. maintained on an ordinary diet, a transient appearance of glycogen is demonstrable in the adipose tissue. If, after the glycogen has disappeared, the insulin injection is repeated, new transient deposition of adipose glycogen is induced. It should be added that different types of adipose tissue differ quantitatively from one another in ability to store glycogen following insulin treatment. In general, deposition occurs most rapidly in the brown interscapulary adipose, less rapidly in mesonterial adipose, and least rapidly in other adipose stores. Seasonal fluctuations, too, are of importance. In summer, the demonstration of deposition necessitates no particular precautions ; in winter, deposition occurs less rapidly and then only if the animals are maintained above 21° C. on a diet of high calorific value, and if relatively large doses of insulin are administered. Protamin-zinc-insulin is of greater effectivity than ordinary insulin. The adipose tissue of rabbits is less active¹. The effect of insulin in this animal is smaller and only detectable after sugar feeding.