[Influence of salmon calcitonin on changes in thyroid hormone concentration and on TSH secretion. II]

The aim of this investigation was determination of salmon calcitonin (SC) administration influence on hypothalamus-pituitary-thyroid axis. The investigation was carried out on a group of 26 patients. The group was divided in two different ways: into people younger and older than 65 years, and into men and women. Investigation protocol consists of 4 days. On the 1st day patients received 100U of SC, on the 2nd day--100U of SC and 0.4 mg TRH, on the 3rd day--0.4 mg TRH, on the 4th day--0.9% solution of NaCl and 5% solution of human albumin. TSH serum concentrations were determined by RIA method. Infusion of SC caused TSH serum concentration increase in all groups. This effect is qualitatively similar but quantitatively different in investigated groups. Administration of SC with TRH causes significantly smaller growth of TSH concentration than observed after infusion of TRH alone. The mechanism of SC influence on pituitary may be similar to the one of TRH.