Inhibitory effects of (+/-)-tetrahydropalmatine on thyrotropin-stimulating hormone concentration in hyperthyroid rats.
The effects of (+/-)-tetrahydropalmatine ((+/-)-THP) on the hypothalamus-pituitary-thyroid system in rats were investigated. Thyroid function experiments indicated that (+/-)-THP produces significant decreases in thyroid function in hyperthyroid rats after 14 days of treatment. These effects were the same as those of propylthiouracil. However, propylthiouracil also decreased thyroid function in normal rats. Measurements of thyrotropin-stimulating hormone (TSH) demonstrated that (+/-)-THP decreased TSH in hyperthyroid rats after 14 days of treatment; however, propylthiouracil increased TSH in hyperthyroid rats. (+/-)-THP had no influence on TSH, or thyroid and pituitary weight in normal and hyperthyroid rats. We conclude that (+/-)-THP has an antithyroid function and the mechanism of action may be related to the inhibition of TSH in the pituitary.
Institute of Chinese Pharmaceutical Sciences, China Medical College, Taichung, Taiwan, Republic of China.
M T
MT
Hsieh
L Y
LY
Wu
D000818:Animals; D013956:Antithyroid Agents / Q000494:pharmacology*; D001600:Berberine Alkaloids / Q000494:pharmacology*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006980:Hyperthyroidism / Q000097:blood* / Q000473:pathology; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000187:drug effects / Q000473:pathology; D013963:Thyroid Hormones / Q000097:blood; D013973:Thyrotropin-Releasing Hormone / Q000097:blood*
D013956:Antithyroid Agents; D001600:Berberine Alkaloids; D013963:Thyroid Hormones; C014215:tetrahydropalmatine; D013973:Thyrotropin-Releasing Hormone