The snake thyroid gland V. effects of hypophysectomy on iodine metabolism in the striped racer,Elaphe taeniura

Summary Thyroidal iodine metabolism in the hypophysectomized snake,Elaphe taeniura, was examined in vivo and in vitro using¹²⁵I. Hypophysectomy decreased, and TSH increased, both in vivo and in vitro thyroidal accumulation and uptake of radioiodine, and the amount of all labelled substances in the thyroid gland. The operation also altered the distribution of the relative amounts of labelled iodoamino acids in vivo, but not in vitro; nor was there any effect on release of these labelled substances in vitro. In view of the paucity of information available on poikilothermic species, the data are discussed in relation to those of hypothysectomized rats.Abbreviations DIT diiodotyrosine - KRPG Krebs-Ringer-phosphate solution, containing glucose - MIT monoiodotyrosine - PTU propylthiouracil - T ₄ thyroxine - TSH thyroid stimulating hormone