OVARIAN LH HCG RECEPTORS AND PLASMA-LEVEL OF LH,17-BETA ESTRADIOL ANDPROGESTERONE IN GONADOTROPIN-INDUCED PCO SYNDROME IN RATS/

The aim of this work was to investigate the morphologic changes, LH/hC G receptor content in the ovaries and plasma levels of LH, progesteron e and estradiol of hypo - and hyperthyroid rats injected with PMSG and hCG. The hypothyroid state was induced by thyreoidectomy (Tr-X) and t he hyperthyroid condition by injections of 40 mu g L-thyroxine daily d uring 21 days (T-4) Gonadotropins were injected during 14 days in dail y doses: PMSG - 5 i. u. and hCG - 10 i. u. The following 8 groups (n = 10-20) were established: control (euthyroid, no treatment), Tr-X, PMS G + hCG, Tr-X + hCG, Tr-X + PMSG, Tr-X + PMSG + hCG, T-4 and T-4 + PMS G. At the end of experiments rats were sacrificed, ovaries weighed, ma croscopically inspected and concentration of LH/hCG receptors was esti mated. In blood plasma the level of LH, progesterone and 17-beta estra diol was also analysed. The experiments showed that injections of PMSG alone, or PMSG + hCG in eu-or hypothyroid rats, appear the most effec tive in induction of PCO syndrome in rats. Low levels of thyroid hormo nes sensitized the ovaries to gonadotropin action, but a hyperthyroid status diminished or inhibited this response. Thyroid function is also essential in production of LH/hCG receptors in the ovaries. In hypoth yroid animals the amount of these receptors was greatly increased, whi le in hyperthyroid animals they decreased. The level of plasma LH, pro gesterone, and estradiol showed insignificantly differences and variou s inconsiderable deviations from norm. These differences were not depe ndent on large doses of gonadotropins, altered thyroid function, or on cystic or luteinizing changes in the ovary.