A COMPARISON OF THE IN-VITRO ACTIONS OF THYROID-STIMULATING HORMONE AND CYCLIC 3′,5′-ADENOSINE MONOPHOSPHATE ON THE MOUSE THYROID GLAND

Abstract

SUMMARY: In the in-vitro assay of Brown & Munro (1967) thyroid-stimulating hormone (TSH) increased the release of radioactive iodine from mouse thyroid glands labelled with ¹³¹i during life. Paper chromatography showed that TSH increased the ¹³¹I-labelling of thyroxine and tri-iodothyronine both in the culture medium and in hydrolysates of the thyroids. Cyclic 3′,5′-adenosine monophosphate (cyclic AMP) also increased ¹³¹I release in this assay and increased the ¹³¹I-labelling of thyronines in the culture medium. The effects on thyroid hydrolysates were less striking. Theophylline potentiated the influence of TSH and cyclic AMP in the assay and, by itself, increased ¹³¹I release and the labelling of iodothyronines in the thyroid without altering the distribution of ¹³¹I in the culture medium. The implications of these results are discussed.