Abstract
Summary
Fifty mature female rats were divided into 5 groups of 10 animals each on the basis of equal thyroxine secretion rate (TSR). Twenty-eight days after the TSR was determined initially, groups III, IV and V were treated with 30, 60 and 90 MRC mU of thyrocalcitonin (TCT)/100 g body weight twice daily intraperitoneally. Groups I and II acted as normal and vehicle treated groups, respectively. The treatment was started 14 days prior to the start of the TSR estimation and continued until the TSR of the animals was estimated. The animals were then sacrificed and the following glands and organs were removed and weighed: ovaries, adrenals, pituitary, thyroid, uterus, liver, kidneys and spleen. Administration of 30 and 90 mU TCT/100 g body weight twice daily for at least 14 days caused a significant (p < .01) decrease in TSR, but the 60 mU dose of TCT did not. Significant (p < .05) increases in weights of the adrenals and liver were noticed in all the treated groups, whereas kidney weight changes were significant only in 60 and 90 mU groups. Exogenous TCT injection has a depressing effect on TSR. The increase in adrenal, liver and kidney weights might be due to nonspecific stress.
We are indebted to Dr. J. P. Aldred, PhD, Department of Pharmacology, Armour Pharmaceutical Company, Kankakee, IL, for the generous donation of porcine calcitonin preparations.
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