Comparative Effects of Long-Acting Thyroid Stimulator and Pituitary Thyrotropin on the Intermediate Metabolism of Thyroid Tissuein Vitro

Abstract

Long-acting thyroid stimulator (LATS) increases the uptake and oxidation of glucose and enhances the formation of lactate by sheep thyroid slices in a manner analogous to the action of pituitary thyrotropin (TSH). LATS also increases phospholipogenesis (indicated by p32 incorporation), but the specificity of individual phospholipld response may be different from that with TSH. LATS stimulates the incorporation of P32 orthophosphate into lecithin and monophospha-tidylinositol to about the same degree, whereas TSH action is directed mainly toward the latter phospholipid. In contrast to TSH, LATS consistently increases the labeling of neutral lipids from U-C14 glucose, although their effects on decreasing the ratio of radioactive triglyceride/-diglyceride are similar.