GSBS Student Publications

Title

Regulation of glycogen metabolism in primary cultures of rat hepatocytes. Restoration of acute effects of glucose in cells from diabetic rats involves protein synthesis

UMMS Affiliation

Graduate School of Biomedical Sciences; Department of Biochemistry

Date

3-25-1987

Document Type

Article

Medical Subject Headings

Animals; Cells, Cultured; Cycloheximide; Dactinomycin; Diabetes Mellitus, Experimental; Enzyme Activation; Glucose; Glycogen; Glycogen Synthase; Glycogen-Synthase-D Phosphatase; Hydrocortisone; Insulin; Liver; Male; *Protein Biosynthesis; Rats; Rats, Inbred Strains; Triiodothyronine

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

Defective acute regulation of hepatic glycogen synthase by glucose and insulin, caused by severe insulin deficiency, can be corrected in adult rat hepatocytes in primary culture by inclusion of insulin, triiodothyronine, and cortisol in a chemically defined serum-free culture medium over a 3-day period (Miller, T. B., Jr., Garnache, A. K., Cruz, J., McPherson, R. K., and Wolleben, C. (1986) J. Biol. Chem. 261, 785-790). Using primary cultures of hepatocytes isolated from normal and diabetic rats in the same serum-free chemically defined medium, the present study addresses the effects of cycloheximide and actinomycin D on the chronic actions of insulin, triiodothyronine, and cortisol to facilitate the direct effects of glucose on the short-term activation of glycogen synthase. The short-term presence (1 h) of the protein synthesis blockers had no effect on acute activation of glycogen synthase by glucose in primary hepatocyte cultures from normal rats. Normal cells maintained in the presence of cycloheximide or actinomycin D for 2 and 3 days exhibited unimpaired responsiveness to glucose activation of synthase. The protein synthesis inhibitors were effective at blocking the restoration of glucose activation of synthase in diabetic cells in media which restored the activation in their absence. Restoration of glycogen synthase phosphatase activity by insulin, triiodothyronine, and cortisol in primary cultures of diabetic hepatocytes was also blocked by cycloheximide or actinomycin D. These data clearly demonstrate that restoration of acute glycogen synthase activation by glucose and restoration of glycogen synthase phosphatase activity in primary cultures of hepatocytes from adult diabetic rats are dependent upon the synthesis of new protein.

Rights and Permissions

Citation: J Biol Chem. 1987 Mar 25;262(9):4000-6.

Related Resources

Link to article in PubMed

Journal Title

The Journal of biological chemistry

PubMed ID

3104335