[Endocrine regulation of the endometrium throughout the menstrual cycle (author's transl)]. / Untersuchungen zur endokrinen Regulation des Endometriums während des mensuellen Zyklus.

PIP: Estradiol, estrone, and progesterone levels in serum and tissue were determined radioimmunologically from 160 endometrium and serum samples taken at various phases of the menstrual cycle in female patients who had undergone either curettage or hysterectomy for medical reasons. In addition, the cytoplasmatic estradiol and progesterone receptor concentrations and the (17beta-HSD) 17-beta-hydroxysteroid dehydrogenase activities in the endometrium were measured. In 132 cases, it was possible to correlate the endometrial histological findings and serum hormone levels with a particular phase of the cycle. The serum concentrations of sexual steroids displayed the usual biphasal pattern for estradiol and estrone with the postovulatory increase in progesterone. The tissue levels of these hormones followed a course partly paralled to and partly opposed to the serum levels. The progesterone profile in tissues essentially matches that in the serum except that the endometrium concentrations showed a marked prevulatory increase, with no appreciable postovulatory rise. The midcycle estradiol peak was also observed in the endometrium. After ovulation, the estradiol concentration in the tissue declined significantly. The changes in estrone levels in the secretory endometrium were at variance with those in the serum, increasing sharply after ovulation. The cytoplasmic estradiol receptor concentration exhibited a maximum in the middle of the proliferative phase and declined steadily over the rest of the cycle. The number of progesterone-binding receptors is only enhanced at midcycle. The concentration changes in the progesterone receptors could be clearly correlated with the estradiol peak in serum and tissue at midcycle. A 10-fold increase in 17beta-HSD activity is observed after ovulation, affecting changes in the tissue/serum estradiol and estrone ratios. The estradiol shifts ratio in favor of the serum during postovulatory phase, whereas the estrone ratio is displaced in favor of the tissue. A regulatory model for the endometrial cells during the menstrual cycle is suggested on the basis of the results obtained.^ieng

Detection of ovulation by a radioreceptor assay for human luteinizing hormone.

A specific, sensitive, and rapid radioreceptor assay (RRA), employing membranes from bovine testes as receptor and [125I]hLH as radioligand, has been developed for measurement of human LH in serum. This RRA was used to determine the time of ovulation in seven women. For comparison, four hourly values around midcycle were measured by RIA. The sensitivity of the RRA was 0.78 ng/ml serum and could be increased by prolonged incubation. The coefficient of within and between assay variation at the 50% inhibition level was 7% and 13%, respectively. The mean index of discrimination (RRA/RIA) was 1.02, expressed by the slope of the regression curve. The coefficient of correlation was 0.97. In all women, the LH surge was detected by RRA, and the subsequent ovulation was verified within 30 h by endoscopic examination of the ovaries, as well as serum progesterone concentrations of more than 5 ng/ml on the fifth day after ovulation. As shown, prospective ovulation timing can be done by this simple and accurate method. The RRA can be useful in infertility therapy such as artificial insemination.

PIP: A 2-hour solid-phase radioimmunoassay (RIA) is described for determination of luteinizing hormone (LH) concentrations to detect ovulation. Time of ovulation was determined in 7 women. For comparison, 4 hourly values around midcycle were measured by 2-hour RIA. The 2-hour RIA sensitivity was .78 ng/ml of serum and could be increased by prolonged incubation. The coefficients of within and between assay variation at the 50% inhibition level were 7 and 13%, respectively. The mean index of discrimination between standard RIA and 2-hour RIA was 1.02, expressed by the slope of the regression curve. The coefficient of correlation was .97. In all women, the LH surge was detected by 2-hour RIA, and the subsequent ovulation was verified within 30 hours by endoscopic examination of ovaries as well as serum progesterone concentrations of more than 5 ng/ml on the 5th day after ovulation. Prospective ovulation timing can be done by this simple, accurate method. The 2-hour RIA can be useful in infertility therapy such as artificial insemination.

Ovulation timing by a radioreceptor assay for human luteinizing hormone.

Since predetermination of ovulation would be helpful in treatment of sterility, a quick, sensitive, and specific radioreceptor assay (RRA) for measurement of actual LH concentrations in human serum has been developed. Using partially purified membrane receptors from bovine testes, our assay system enabled precise measurement of LH within 4 hours. The detection limit of the present method is 0.78 ng LER 960/ml serum. The method was used to detect ovulation during four observation cycles each in eleven women who were undergoing treatment for infertility, such as recommended intercourse or artificial insemination because of reduced fertility of their husbands. In all women ovulations could be predicted by LH surge and were verified by laparoscopy within 36 hours. Insemination was carried out at the time of the characteristic increase of LH values around mid-cycle. Pregnancy occurred in three women during the observation period.