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The present study was undertaken to determine the production of leukotriene B4 (LTB4) by cultured human luteal cells in the mid-luteal phase using a reverse phase column (C8). The luteal cells were cultured with or without hCG at 100 ng/ml for 8 days. In the preliminary experiment, methods for extracting culture media samples were assessed prior to radioimmunoassay. Reverse phase column C8, but not C18, made possible the determination of LTB4 produced by human luteal cells. Progesterone (P) production by cultured luteal cells reached its maximum on day 4 following exposure to hCG, and then declined gradually. The concentrations of LTB4 produced by luteal cells varied from 100 to 500 pg/10(5) cells/2 days. However, exposure to hCG did not affect LTB4 production by cultured luteal cells. The level of LTB4 in culture medium (115.0 +/- 37.8 pg/10(5) cells/2 days) was reduced on day 4, but increased thereafter. LTB4 production appeared to decrease concomitantly with increased P production of cultured luteal cells. In conclusion, cultured luteal cells produced considerable amounts of LTB4 throughout the entire culture period. These results suggest that lipoxygenase activity of luteal cells may be closely related to steroidogenic potential.

Unlabelled: It is conceivable that luteal function is varied with different menstrual cycles. A study was therefore undertaken to investigate for changes in luteal function during consecutive menstrual cycles., Methods: From those women receiving ambulatory treatment at the hospital 30 displaying a biphasic basal body temperature (BBT) curve were chosen for the study. BBT records were obtained from each of these women for at least 3 consecutive cycles and a total of 194 cycles thus rendered available were evaluated for the pattern of BBT, the duration of high phase (DHP), high phase score (HPS) and planimetric luteal index (PLI). Twenty of these 30 women were subjected further to endometrial dating at the 7th-8th day of high phase with simultaneous determinations of serum estradiol (E2), progesterone (P) and prolactin (PRL) during 2 consecutive cycles., Results: The incidences of abnormal values of the parameters for at least one of the consecutive cycles studied were: DHP; 13.3% pattern; 50-100%, HPS; 40.0%, PLI; 13.3%, E2; 25%, P; 25%, PRL; 30%, endometrial dating; 65%. These results indicate a considerable variability of luteal function.

In strains LT/Sv and LTXBJ mice, susceptible to spontaneous ovarian teratocarcinogenesis, ovarian teratomas are derived from parthenogenetically activated ovarian eggs. The follicles containing the parthenotes are the abnormal ones in which granulosa cells show histochemically high activity of beta-glucuronidase (beta-G). To investigate whether ovarian teratocarcinogenesis depends on the genetic nature of eggs themselves or the microenvironment in the abnormal follicles, we used chimeras derived from aggregates of eight-cell embryos of strains LTXBJ or (LTxLTXBJ) F1 and of normal nonsusceptible strain C3H/HeJ which shows low activity of beta-G genetically. The original strain of teratomas and follicles in chimeras were histochemically determined by activity of beta-G as a marker. The results showed that both teratomas and the follicles containing parthenotes originate from the susceptible strains. Then, we examined for presence of activated oocytes, teratomas and corpora lutea in LT ovaries untreated or treated with PMSG-HCG implantation. These results showed that parthenogenetic blastocysts closely adhere to the follicle tissue as if a kind of and develop to post implantation stages in the ovaries in which corpora lutea were formed near the parthenotes. In conclusion, it was suggested that ovarian parthenogenesis in mice occurs most frequently when eggs with genetically susceptible nature, were exposed to the microenvironment produced by the abnormal follicles, and these parthenotes adhere to the ovarian tissues and differentiate three germ layers by some roles of corpora lutea and undergo teratocarcinogenesis.

The influences of exogenous hCG on rat (pseudopregnant and pregnant) ovarian hCG receptors and the presence of hCG-like material in the rat placenta were investigated. Ovarian hCG receptors in immature rats induced by PMS-hCG priming maintained a binding activity for about 20 days after hCG injection. The administration of hCG to pseudopregnant rats caused time and dose related changes in ovarian 125I-hCG binding percentage and the concentration of serum progesterone. The injection of hCG produced a slight decrease in the binding percentage and was followed by a marked decrease. The measurement of ovarian tissue hCG concentration by radioimmunoassay suggested that the initial loss of binding percentage was associated with the occupancy of receptors by the exogenous hCG, but the major loss of binding percentage might not be attributed to the receptor occupancy. The active process might be involved in the mechanism of receptor loss. The progesterone concentration in sera had a tendency to increase after the injection of 25IU hCG, while it decreased after the injection of 125IU hCG. The 125I-hCG binding percentage to ovaries and the serum concentration of progesterone reached their maximal values from mid to late pregnancy and declined as parturition approached. After the injection of hCG into pregnant rats, the binding percentage rapidly decreased and the serum concentration of progesterone increased. Thereafter the binding percentage recovered on the 4th day after the injection of hCG. On that day, though the concentration of hCG in ovarian tissue was barely detectable, the binding percentage was significantly low compared to the control level. The rat placenta (8th to 21st day of pregnancy) contained hCG-like activities, but they could not be detected in peripheral blood. In the treatment of hCG-antibody in pregnant rats, the binding percentage did not change but the serum concentration of progesterone showed a tendency to decrease to the control level. These studies show that hCG receptors exist as free sites in pregnant and pseudopregnant rat ovaries and may be regulated by down regulation after the treatment of large amounts of exogenous hCG. We found that hCG-like material in rat placenta determined by radioimmunoassay might serve as a luteotropin during pregnancy.

Activities of the steroidogenic enzymes involved in functional luteolysis and PGF2 alpha induced luteolysis were determined in PMSG-hCG primed immature rats to elucidate the luteolytic effects of PGF2 alpha. Plasma progesterone (P4), plasma 20 alpha dihydroprogesterone (20 alpha OHP4), in vitro production of pregnenolone (P5) from endogenous cholesterol in ovarian mitochondria (8,000 X g pellet; Mt), activities of 3 beta hydroxysteroid dehydrogenase (3 beta HSD) in ovarian microsome (105,000 X g pellet; Ms) and 20 alpha hydroxysteroid dehydrogenase (20 alpha HSD) in ovarian cytosol(105,000 X g supernatant; Sup) were determined. For the investigation of intramitochondrial transport of cholesterol, measurement of free cholesterol (FCh) of Mt and the Lineweaver-Burk plotting for cholesterol side-chain cleavage enzyme (CSCC), prepared by osmotic shock and sonication of Mt, were carried out. Functional life span of the rat corpus luteum was estimated as 12 days post hCG treatment from plasma P4. As plasma P4 decreased, concomitant increase in plasma 20 alpha OHP4 was observed. In vitro production of P5 in Mt correlated well with plasma P4 levels, indicating cholesterol side-chain cleavage reaction is the rate limiting step involved in ovarian steroidogenesis. In contrast, both values of Km and Vmax of CSCC did not change between day 7, on which the highest value of plasma P4 observed, and day 12, on which functional luteolysis was ascertained from plasma P4. Both FCh of Mt and the activity of 3 beta HSD in Ms remained unchanged during the functional life of the corpus luteum. The activity of 20 alpha HSD in Sup increased from day 10 post hCG treatment in accordance with plasma 20 alpha OHP4. These results indicate that 1) decrease in availability of FCh to CSCC within mitochondria and 2) increase in catabolism of P4 into inactive progestin, 20 alpha OHP4, may play key roles in the functional luteolysis. To compare the events observed in functional luteolysis with PGF2 alpha induced luteolysis, the animals were treated either with PGF2 alpha (1 mg/rat; s.c.), cycloheximide (5 mg/rat; i.p.; CX), or vehicle on day 7 post hCG treatment, and sacrificed 1 hour later for the analyses mentioned above. Both plasma P4 and in vitro production of P5 in Mt decreased significantly with PGF2 alpha or CX treatment, whereas the FCh of Mt and the activity of CSCC remained unchanged with PGF2 alpha treatment. Both plasma 20 alpha OHP4 and 20 alpha HSD in Sup increased with PGF2 alpha treatment. However, CX suppressed both of them.(ABSTRACT TRUNCATED AT 400 WORDS)

Ovarian stimulation and corpus luteum function in human in vitro fertilization and embryo transfer were investigated. Thirty-three cycles were treated with clomiphene citrate (CC) alone and 56 cycles with a CC/human menopausal gonadotropin (hMG) combination, and the latter was divided into three groups in the luteal phase; untreated (CC/hMG-NO) (n = 21), treated with progesterone (CC/hMG-P) (n = 23), and treated with human chorionic gonadotropin (hCG) (CC/hMG-hCG) (n = 12). There were many more increases in the number of aspirated follicles, recovered oocytes, and transferred embryos in the CC/hMG group than in the CC group. A significant correlation was found between the numbers of aspirated follicles and serum estradiol (E2) peaks in the follicular phase, and also between serum E2 peaks in the follicular phase and serum progesterone (P) maximum levels in CC and CC/hMG-NO. No significant difference was observed in serum P levels in the midluteal phase among four groups, though their levels were given in the following order; CC/hMG-hCG greater than CC/hMG-P greater than CC/hMG-NO. P/E2 ratios for the luteal phase in the CC/hMG-hCG group were significantly higher than those of other groups, but the pregnancy rate for the CC/hMG-hCG group was the lowest in the four groups. In conclusion, the high P and high P/E2 ratios following luteal treatment were not necessarily connected with pregnancy.