Further Studies on the Regulation of Calcitonin Release In Vitro[*] [**]

Abstract

The effects of a number of hormones and biologically active agents on release of calcitonin by thyroid slices was examined. Previous studies from this laboratory had demonstrated enhanced release with calcium, magnesium, glucagon, dibutyryl cyclic adenosine 3',5'-monophosphate and theophylline. In the present studies, secretion was augmented by the pituitary hormones thyrotropin and prolactin, by the enteric hormones gastrin tetrapeptide and pancreozymin and by thyroxine and prostaglandin E₁. Release was increased by serotonin, acetylcholine, methacholine, epinephrine and norepinephrine and inhibited by dopamine. Betaadrenergic blockade with dl-propranolol diminished the stimulatory effects of epinephrine on calcitonin release and alpha-adrenergic blockade with phentolamine prevented the inhibitory effects of dopamine. Secretin, parathyroid hormone, 25-hydroxycholecalciferol, adrenocorticotropin, follicle-stimulating hormone, luteinizing hormone, growth hormone and insulin were without effect. The possible significance of these observations is discussed.

Key words

Calcitonin - Calcium - Thyrotropin - Prolactin - Gastrin - Pancreozymin - Prostaglandin E₁

1 Presented in part at the Annual Meeting of the Midwestern Section, American Federation for Clinical Research, Chicago, Illinois, November 5, 1970. Clin. Res. 18: 355.

1 Presented in part at the Annual Meeting of the Midwestern Section, American Federation for Clinical Research, Chicago, Illinois, November 5, 1970. Clin. Res. 18: 355.

2 Supported in part by Grant AM 15009-03 from the U.S. Public Health Service and by Research Funds from the Veterans Administration.