Abstracts

10. Reproductive biology

315

10A. Reproductive biology : Menstrual cycle

331. Serum estrogen, LH and FSH levels in response to LH-RH during the menstrual cycle in women NISHI. N..t OKARU, T.. SAITO, M., KUMASAKA, T., KATO, H., YAOI, Y. and ARIMURA, A.,t Department of Gynaecology and Obstetrics. Tokyo Medical and Dental University, Tokyo, Japan, VA Hospital and TDepartment of Medicine, Tulane University School of Medicine, New Orleans, La. U.S.A.

Serum estrogen (E), LH and FSH were determined by radioimmunoassay after SC injection of 200 pg of synthetic LH-RH at various phases of the menstrual cycle in normal women. Serum E levels increased significantly 15 min after LH-RH at midcycle and at midluteal phase, returned to preinjection levels at 1545 min, but rose again l-2 h later. In the follicular phase, serum E levels remained unchanged for 2 h after LH-RH but increased significantly at 3 h, then decreased again at 4 h. In all phases of the cycle, serum LH and FSH levels rose significantly 15 min after LH-RH. Peak LH and FSH levels were observed at 30min and 30-120min, respectively. Thus, the initial rise in serum E levels at midcycle and in the luteal phase occurred in accordance with the rise in serum LH, but the second elevation of serum E levels was not related to either LH or FSH levels. E excretion in the overnight urine collection following the LH-RH did not increase, suggesting that E was rapidly excreted. These findings may be interpreted as follows: At midcycle and in the luteal phase, but not in the follicular phase, the ovarian follicles rapidly respond to increased gonadotropin levels by releasing preformed E. Increase of serum gonadotropins may also stimulate the synthesis of E. as reflected by a delayed increase of serum E levels.

332. Peripheral plasma concentrations of prostaglandin (PC) F,, and Fzor in relation to estradiol (E2) and progesterone (P) during normal menstrual cycles PATRONO, C.. GROW-BELLONI, D., CIABATTONI, G., SERRA, G. B. and DELL’ACQUA, S., Departments of Pharmacology and Obstetrics and Gynaecology, Cath- olic University, Rome, Italy

Although some experimental evidence has been provided suggesting that ovarian hormones may regulate prostaglan- din (PG) synthesis and release, especially from the uterus, substantive information in humans is not available. The present study was undertaken in an attempt to correlate changes in peripheral plasma concentrations of PGF,, and PGF,, with corresponding levels of estradiol (E,) and progesterone(P) during normal menstrual cycles. Six healthy women were studied daily during one or two successive cycles. P was measured by competitive protein binding assay. PGF,,, PGF*,, E, and LH were measured by specific radioimmunoassays. All observations were standardized to the day of the LH peak. PGF,, concentrations showed wide fluctuations from day to day, although tended to be slightly higher in the follicular phase. PGF,, levels showed a quite different pattern, characterized by a relatively constant plateau at midcycle and a significant rise in the luteal phase, following the increase in P concentrations.

These data suggest the existence of possibly distinct regulatory mechanisms for PGF,, and PGF,, synthesis and release. Furthermore, they appear to be consistent with preliminary results obtained in vitro indicating enhanced PGF2, release from fragments of human endometrium following exposure to E, and P.

333. Releke of progesterone (P) and 17-estradiol (E2) by human ovaries stimulated in vivo by HCG DELL’ACQUA, S., SERRA. G. B., LUCISANO, A.. MONTEMURRO. A., ARNO, E. and CINQUE, B., Department of Obstetrics and Gynaecology, Univer- sita Cattolica del Sacro Cuore, Rome, Italy

Although experimental evidence of LH action on ovarian steroidogenesis in the human species has been acquired, substantial data in viva are lacking. Four fertile patients, undergoing laparotomy for uterine fibromatosis, have been injected rapidly in the cubital vein with 30,000 I U of HCG at the mid-luteal phase of the cycle. Blood sampling from both ovaries has been obtained at short intervals by insertion of a small needle connected with a short tube in one of the ovarian veins. P was measured by competitive protein binding and E2 by specific radioimmunoassay. Basal values of P and E, in the blood from the ovary with a corpus luteum were significantly higher than in sampling from the opposite ovary and cubital vein. Following the administra- tion of HCG, the P concentration measured in the blood from the ovary with a corpus luteum increased 34 times over the mean basal levels, reaching the peak value in about 3&40min. No significant changes were observed in the blood from the contralateral ovary. Similar results have been obtained in the release pattern of E,. These data are in agreement with previous observations in animals and confirm: (a) That HCG during the luteal phase acts as an acute stimulus inducing a significant and prompt release of both P and E,; and (b) that not only the production of P, but also of E, occurs mostly in the ovary with a corpus luteum.

334. Factors regulating plasma aldosterone concentration during the menstrual cycle KAULHAUSEN, H., BENKER, G., FRITZSCHE, G. and BREUER, H., Institut fiir Klinische Biochemie und Frauenklinik der Universitlt Bonn, 53 Bonn-Venus- berg, Federal Republic of Germany

Plasma renin activity (PRA), plasma renin substrate concen- tration (PRS) and plasma aldosterone concentration (PA) were studied simultaneously with respect to the regulation of aldosterone during the menstrual cycle. Blood samples were taken every second day throughout the cycle from 5 healthy young women before getting up in the morning. PRA and PRS were measured by radioimmunoassay of angiotensin 1; for PRS estimation, human renin was added in excess to the incubation. PA was determined radio- immunologically after previous purification of the plasma extracts by paper chromatography. Body basal temperature was biphasic in four out of five subjects. These 4 women revealed an increase of PA during the late follicular as well as during the luteal phase; in the fifth subject, a rise of PA was found only at the end of the cycle. The pattern of PRA coincided in all women investigated. The variations of PRS