Mt. Hsieh et Ly. Wu, INHIBITORY EFFECTS OF (+ -)-TETRAHYDROPALMATINE ON THYROTROPIN-STIMULATING HORMONE CONCENTRATION IN HYPERTHYROID RATS/, Journal of Pharmacy and Pharmacology, 48(9), 1996, pp. 959-961
The effects of (+/-)-tetrahydropalmatine ((+/-)-THP) on the hypothalam
us-pituitary-thyroid system in rats were investigated. Thyroid functio
n experiments indicated that (+/-)-THP produces significant decreases
in thyroid function in hyperthyroid rats after 14 days of treatment. T
hese effects were the same as those of propylthiouracil. However, prop
ylthiouracil also decreased thyroid function in normal rats. Measureme
nts of thyrotropin-stimulating hormone (TSH) demonstrated that (+/-)-T
HP decreased TSH in hyperthyroid rats after 14 days of treatment; howe
ver, propylthiouracil increased TSH in hyperthyroid rats. (+/-)-THP ha
d no influence on TSH, or thyroid and pituitary weight in normal and h
yperthyroid rats. We conclude that (+/-)-THP has an antithyroid functi
on and the mechanism of action may be related to the inhibition of TSH
in the pituitary.