Glycogen metabolism of the thyroid.

Abstract

Thyroid-stimulating hormone (TSH) and dibutyryl cyclic 3′,5′-AMP (dbcAMP) enhanced glycogenolysis in bovine and canine thyroid slices. In canine thyroid slices, prostaglandin E1 and F1α, like TSH and dbcAMP, enhanced glycogenolysis as well as organic binding of iodine, including formation of thyroxine. In bovine thyroid slices, however, despite their glycogenolytic effect, dbcAMP and low concentration of TSH (0.8 mU/ml) did not stimulate organic binding of iodine. Sodium fluoride accelerated glycogenolysis and thyroid hormone formation in both canine and bovine thyroid slices. In bovine thyroid slices, epinephrine and serotonin stimulated both glycogenolysis and organic binding of iodide, while insulin, ACTH, FSH and growth hormone stimulated neither glycogenolysis nor organic binding of iodine’ These findings suggest that 1) TSH-induced glycogenolysis in thyroid slices is mediated by cyclic 3′,5′-AMP, 2) agents which enhance organic binding of iodine generally seem to be glycogenolytic, but 3) stimulatio...