STIMULATION OF THYROID METABOLISM BY THYROTROPIN CYCLIC 3'-5'-AMP DIBUTYRYL CYCLIC 3'-5'-AMP AND PROSTAGLANDIN E1

Under appropriate conditions, thyrotropin stimulated the binding of [131I]iodide to proteins in sheep, calf and dog thyroid slices. In dog thyroid slices, thyrotropin, dibutyl cyclic 3′:5′‐adenosine monophosphate, and cyclic 3′:5′‐AMP in the presence of caffeine, stimulated glucose oxidation at C‐1, [131I]iodide binding to proteins and intracellular colloid droplet formation; no such effect was obtained with butyrate, 5′‐AMP, ADP, ATP or caffeine. The stimulation of [131I]iodide binding to proteins and of glucose oxidation at C‐1 by low concentrations of thyrotropin (0.5 mU/ml) was enhanced in the presence of caffeine. These data support the hypothesis that many effects of thyrotropin on thyroid tissue are, to a large extent if perhaps not exclusively, secondary to the activation of thyroid adenyl cyclase by this hormone. Fluoride, which activates adenyl cyclase in acellular systems, mimicked the effects of thyrotropin on glucose C‐1 oxidation and on [131I]iodide binding to proteins. Prostaglandin E1, which in some tissues increases the intracellular levels of cyclic 3′:5′‐AMP, also stimulated these metabolic steps. No effect of fluoride and prostaglandin E1 on intracellular colloid droplet formation was observed. Copyright © 1969, Wiley Blackwell. All rights reserved