Effects of the dopaminergic system on release of TSH and thyroid hormone in rats

Lee, Sang-woo; Kim, Jin-sang; Han, Jeong-hee

Korean Journal of Veterinary Research 1992;32(2):165-173.

Sang-woo Lee¹, Jin-sang Kim², Jeong-hee Han²

¹College of Veterinary Medicine, Chonbuk National University
²Department of Veterinary Medicine, Kangwon National University

랫드에서 TSH와 갑상선 호르몬에 미치는 dopamine계의 영향

이상우¹, 김진상², 한정희²

¹전북대학교 수의과대학
²강원대학교 수의학과

Abstract

The present study was carried out to investigate the effects of dopaminergic drugs and the role of specific dopamine(DA) receptors on the release of TSH, $T_4$ and $T_3$. Serum TSH levels (cold-induced, $4{^{circ}C}$) were determined using RIA(radioimmunoassay) at 30 min after administration of dopamine agonists and antagonists. Serum $T_4$ and $T_3$ levels were detected after these dopaminergic drugs were administered subcutaneously twice a day for a week. The results of the study are summarized as follows : Apomorphine, a nonspecific DA receptor agonist, produced a dose-depedent decrease in serum TSH, $T_4$ and $T_3$ levels. However, only low doses (0.3, 1.0mg/kg) of SKF38393, a specific $D_1$-receptor agonist, produced a decrease in serum lelvels of TSH. I,Y171555, a specific $D_2$-receptor agonist, produced a dose dependent decrease in serum TSH, $T_4$ and $T_3$ levels. However, SCH23390, a specific $D_1$-receptor antagonist, produced a decrease except in serum T levels which were increased dose dependently. High doses (1.0, 3.0mg/kg) of sulpiride, a specific $D_2$-receptor antagonist, made a increase in the serum levels of TSH and $T_3$. The effects of dopaminergic drugs in serum TSH and $T_4$ levels was potentiated by the pretreatment of apomorphine. The overall results of this study suggest that the regulation of TSH, $T_4$ and $T_3$ secretion were mediated via specific $D_1$ and $D_2$ receptor.

Key Words: dopamine, TSH, thyroid hormone