Gonadotropin receptors in human corpora lutea of term pregnancies

The function of the corpus luteum of pregnancy in ovulatory dysfunction and luteal phase deficiency

Relatively little knowledge exists of corpus luteum function in early pregnancy after the successful treatment of ovulatory dysfunction or luteal phase deficiency. To assess the activity of the corpus luteum of such patients, human chorionic gonadotropin (hCG) and 17-hydroxyprogesterone (17-OH-P) levels were determined in serum samples obtained from normal women (44 patients), women with ovulatory dysfunction (10 patients), and women with luteal phase deficiency (7 patients); all determinations were made during conceptive cycles, and sampling continued into the first trimester of pregnancy. There were no statistically significant abnormalities of hCG levels when infertility patients were compared with control patients. According to the premise that 17-OH-P levels reflect corpus luteal function, there appeared to be adequate function in pregnancies after progesterone treatment of luteal phase deficiency. In pregnancies following ovulation induction with clomiphene, the corpus luteum function, on the basis of 17-OH-P levels, was significantly increased in magnitude and duration. These results have clinical implications with regard to supplemental hormone therapy in early pregnancy.

The presence of gonadotropin binding sites in the intracellular organelles of human ovaries

The nuclei (N), plasma membranes (PM), mitochondria-lysosomes, rough endoplasmic reticulum, and combined (light, medium, and heavy) Golgi (G) fractions were isolated from human ovaries. The purities of these fractions were evaluated by assays of appropriate marker enzymes, which revealed that some fractions were very pure but that others had minor contamination. When tested, all of the fractions exhibited 125I-labeled human chorionic gonadotropin (125I-hCG)-specific binding. This intracellular 125I-hCG binding was not due to PM contamination because: (1) N, which had no detectable 5'-nucleotidase (5'-NE) activity, a marker for PM, exhibited 125I-hCG-specific binding; (2) the G, which had only a fraction of the 5'-NE activity of PM, exhibited as much binding as PM; and (3) the ratios between specific 125I-hCG binding and 5'-NE activity in other fractions were not the same as for PM. They should have been the same if PM contamination was responsible for the 125I-hCG binding observed in other organelles. In conclusion, our results demonstrate that gonadotropin-binding sites are present in various intracellular organelles as well as in PM of human ovaries.