GLUCOSE-HOMEOSTASIS IN THYROXINE-TREATED BHE CDB RATS FED CORN-OIL OR HYDROGENATED COCONUT OIL

Glucose turnover was assessed in BHE rats fed either a 6% corn or hydrogenated coconut oil diet and treated with 10 mug thyroxine (T4/100 g body weight/day or untreated. Regardless of fat souce, measures of fractional irreversible glucose turnover and Cori cycle activity were higher in T4-treated rats than in control rats. T4 also increased the alanine to glucose conversion. Treatment with T4 resulted in less muscle and hepatic glycogen. Lipogenesis was greatly increased in the rats fed hydrogenated coconut oil and this effect was potentiated by T4 treatment. Blood glucose levels were also lower in this group, suggesting that this blood glucose lowering was due to a combination of treatment effects on glycogenolysis and lipogenesis. It would appear that the main effect of T4 was to alter the sources of glucose in the total glucose pool in the body, and that the differences in glucose oxidation, synthesis, and recycling were a reflection of the body's adaptation to this reduction.