Synergism of thyroid hormone and high carbohydrate diet in the induction of lipogenic enzymes in the rat. Mechanisms and implications.
Open Access
- 1 May 1980
- journal article
- research article
- Published by American Society for Clinical Investigation in JCI Insight
- Vol. 65 (5), 1126-1134
- https://doi.org/10.1172/jci109766
Abstract
We have investigated the relationship between the administration of triiodothyronine (T3) and a high carbohydrate (CHO) fat-free diet in the induction of lipogenic enzymes in two rat tissues, liver, and fat. Male thyroidectomized rats were treated with graded daily doses of T3 and either supplemented with a high CHO diet or left on a regular diet. Enzymes studied included malic enzyme (ME), fatty acid synthetase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase. In the liver, all four lipogenic enzymes showed a synergistic response between T3 administration and high CHO feeding. In fat, ME also responded synergistically. The interaction was reflected in an increased sensitivity to T3. The dose of T3 required to achieve 50% maximal response was reduced three- to seven-fold by the high CHO diet. This phenomenon could not be attributed to a dietary-induced alteration either in T3 metabolism or in number or affinity of the T3-nuclear receptors. Moreover, studies of the relative rate of synthesis of ME suggested a simultaneous time of onset in the induction of ME, within 2 h after the application of either T3 or CHO. Thus, it is unlikely that either stimulus is secondary to the other. Since parallel experiments from this laboratory (Towle, Mariash, and Oppenheimer,1980.Changes in hepatic levels of messenger ribonucleic acid for malic enzyme during induction by thyroid hormone or diet. Biochemistry. 19: 579-585.) show that ME induction both by CHO and T3 is mediated by an increase in specific messenger RNA for ME, the interaction of T3 and the dietary factor occurs at a pretanslational level.This publication has 37 references indexed in Scilit:
- Thyroid Hormone Action at the Cellular LevelScience, 1979
- Quantitation of messenger RNA levels for rat liver 6-phosphogluconate dehydrogenase.Journal of Biological Chemistry, 1978
- Stimulation of the synthesis of hepatic fatty acid synthesizing enzymes of hypophysectomized rats by 3,5,3′-l-triiodothyronineArchives of Biochemistry and Biophysics, 1976
- [6] Fatty acid synthase from rat liverMethods in Enzymology, 1975
- Apparent Positive Cooperative Effects in Cyclic AMP and Corticosterone Production by Isolated Adrenal Cells in Response to ACTH AnaloguesEndocrinology, 1974
- IN VITRODEMONSTRATION OF SPECIFIC TRIIODOTHYRONINE BINDING SITES IN RAT LIVER NUCLEI12Journal of Clinical Endocrinology & Metabolism, 1974
- Enzyme Activities Related to Fatty‐Acid Synthesis in Liver and Adipose Tissue of Rats Treated with TriiodothyronineEuropean Journal of Biochemistry, 1972
- The effect of dietary carbohydrate and fat on the synthesis of rat liver 6-phosphogluconate dehydrogenaseBiochimica et Biophysica Acta (BBA) - General Subjects, 1971
- Rat liver glucose 6-phosphate dehydrogenase. Regulation by carbohydrate diet and insulin.1971
- INFLUENCE OF THYROID FUNCTION ON CARBOHYDRATE METABOLISM AND A NEW METHOD FOR ASSESSING RESPONSE TO INSULINJournal of Clinical Endocrinology & Metabolism, 1961