Hormonal regulation of ovarian folliculogenesis in rhesus monkeys: I. Concentrations of serum luteinizing hormone and progesterone during laparoscopy and patterns of follicular development during successive menstrual cycles

Chronic ethanol drinking increases during the luteal menstrual cycle phase in rhesus monkeys: implication of progesterone and related neurosteroids

RATIONALE

Sporadic reports of alcohol consumption being linked to menstrual cycle phase highlight the need to consider hormonally characterized menstrual cycle phase in understanding the sex-specific effects of risk for alcohol drinking in women.

OBJECTIVES

We investigated the association between menstrual cycle phase, characterized by circulating progesterone and menses, with accurate daily alcohol intakes in rhesus monkeys, and the contribution of progesterone derived neuroactive steroids to cycle-related alcohol drinking.

METHODS

Menses (daily) and progesterone (2-3×/week) were obtained in female monkeys (n = 8, 5 ethanol, 3 control) for 12-18 months. Ethanol monkeys were then induced to drink ethanol (4% w/v; 3 months) and given 22 h/day access to ethanol and water for approximately 1 year. In selected cycles, a panel of neuroactive steroids were assayed during follicular and luteal phases from pre-ethanol and ethanol exposure.

RESULTS

There were minimal to no effects of ethanol on menstrual cycle length, progesterone levels, and follicular or luteal phase length. The monkeys drank more ethanol during the luteal phase, compared to the follicular phase, and ethanol intake was highest in the late luteal phase when progesterone declines rapidly. Two neuroactive steroids were higher during the luteal phase versus the follicular phase, and several neuroactive steroids were higher in the pre- vs. post-ethanol drinking menstrual cycles.

CONCLUSIONS

This is the first study to show that normal menstrual cycle fluctuations in progesterone, particularly during the late luteal phase, can modulate ethanol intake. Two of 11 neuroactive steroids were selectively associated with the effect of cycle progesterone on ethanol drinking, suggesting possible links to CNS mechanisms of ethanol intake control.

Are intra follicular estradiol and oocytes quality in women undergoing assisted reproductive technology different between the right and left ovaries? An observational study

Objective

Controlled Ovarian Stimulation (COS) for In-Vitro Fertilization (IVF) or Intracytoplasmic Sperm Injection (ICSI) is considered as an assisted reproduction technology. There are established structural and biological differences between both ovaries which may affect their responsiveness to COS. Whether the right or the left ovary responds superior to COS is a question which is unresolved in the literature.

Study design

The present study was conducted as a prospective observational to make a comparison between right and left ovaries’ oocytes based on oocyte quality and follicular fluid estradiol level. A total of 100 infertile women who had referred to Infertility and Reproductive Health Research center at Shahid Beheshti University of Medical Sciences, Tehran, Iran, were investigated.

Results

The total number of very good and good oocytes were 63.01% vs. 50.3%, and immature and interstitial oocytes were 36.99% vs. 49.6% in the right and the left ovaries, respectively. There were no significant differences between oocyte rates between the two ovaries (P > 0.05).

Conclusion

Good and very good quality oocytes and fertilization rate (P < 0.001) are higher in the right ovary compared with the left ovary; however, no significant difference was observed between the right and the left ovaries in oocyte yields and cleavage rates. Moreover, despite higher follicular estradiol levels in the left ovary, there was no relationship noticed between follicular fluid estradiol and oocyte quality among oocytes of each ovary.

The laterality of ovulation: how far does it matter?

The laterality of ovulation, or the side at which ovulation occurs, was the subject of much research in the past century, but it was discussed merely as an interesting physiologic issue in all primates. In the last few years, the increasing development of infertility treatment has drawn the attention of researchers to the clinical aspects of this phenomenon. In the review, we discuss the nature of ovulation side and how far it can influence pregnancy outcome in infertile women treated with different modalities.

Evaluation of ultrasonography for monitoring follicular growth in rhesus monkeys

The purpose of this study was to determine if the ovaries and uterus of rhesus monkeys could be visualized by ultrasonography and to detect changes associated with follicular growth and ovulation. Animals were examined during 15 menstrual cycles, for an average of nine consecutive days. Ultrasonic recordings were correlated with hormonal parameters (estradiol 17beta, E(2); luteinizing hormone, LH; and progesterone, P) and laparoscopic findings. The uterus and both ovaries were observed in more than 90% of the examinations. A dominant follicle (DF) was identified during all ovulatory cycles, on average 1 d preceding the E(2) peak. The maximal diameter of the DF ranged from 3 to 7 mm. Laparoscopic examinations to determine the site of the DF confirmed ultrasonic findings in 10 of 14 cycles (P < 0.1). There was no significant difference in the size of the dominant and contralateral ovaries; however, more follicles with a diameter of 2 to 7 mm were found on the dominant ovary (P < 0.05). Two animals stimulated with exogenous gonadotropins showed a linear increase in ovarian size for 6 d prior to oocyte recovery (P < 0.05), reflecting an increase in the number of developing follicles. Ultrasonography can be used to identify the DF during spontaneous cycles in rhesus monkeys and to monitor the response of monkeys to exogenous gonadotropins.

Characteristics of human ovulation in natural cycles correlated with age and achievement of pregnancy

BACKGROUND

The aim of this study was to evaluate whether characteristics of human ovulation correlate with age and pregnancy potential.

METHODS

Two groups of women with regular menstrual cycles were included (i.e. one fertile and one infertile group), which were divided into four age groups (< or =29, 30-34, 35-39, > or = 40 years). Monitoring included observations of follicular phase length, whether ovulations occurred from the left or right ovary, the pattern of ovulations in succeeding natural cycles and, in a subset of women, early follicular phase FSH concentrations.

RESULTS

Ovulation moving from one ovary to the other in two consecutive cycles (i.e. contralateral ovulation) was inversely correlated with age, showing a ratio of contralateral ovulation per contra plus ipsilateral ovulations (C/C+I) of 62% in women <29 years, gradually decreasing to 42% in women >40 years. The ratio of right-sided ovulation per right plus left-sided ovulations (R/R+L) was unrelated to age and remained almost constant at a level of approximately 55%. The follicular phase length was inversely correlated with age, being 16.2 +/- 2.9, 15.4 +/- 2.9, 14.8 +/- 2.8 and 13.7 +/- 1.3 days in women < 29, 30-34, 35-39 and >40 years of age respectively. The follicular phase length was similar when comparing ovulations occurring from the right and left ovary, but comparing two successive cycles, the length of the follicular phase of the second cycle, showing contralateral ovulation, was shorter than ipsilateral ovulation with two consecutive ovulations in the same ovary. The pregnancy rate of the four groups decreased with age, being 14, 12, 5 and 3% respectively. The C/C+I ratio correlates with pregnancy rate and follicular phase length, and inversely correlates with basal FSH, whereas R/R+L is unrelated to age and pregnancy rate.

CONCLUSIONS

Human ovulation shows characteristics related to age. The interaction between the two ovaries seems to be most pronounced in the younger years, where ovulations jump from one ovary to the other more frequently than later on in life. The C/C+I ratio shows a clear correlation with age and pregnancy rate.

Right-sided ovulation favours pregnancy more than left-sided ovulation

The aim of this study was to evaluate whether frequency of ovulation and fertility potential of oocytes from the two ovaries differed in regularly menstruating women (1057 cycles of 856 fertile women and 1033 cycles of 258 infertile women). For both fertile and infertile women ovulation from the right ovary occurred more often than from the left ovary (55 versus 45%; P: < 0.005). In infertile women follicular phase length was similar for right- and left-sided ovulation. However, infertile women treated with intrauterine insemination (IUI) or in-vitro fertilization (IVF) showed a pregnancy rate in connection with right-sided ovulation (13%) which was higher than that of left-sided (9%). The ratio of pregnancies deriving from the right ovary per total number of pregnancies was similar in infertile and fertile women (64.6%, 73/113 and 63.4%, 361/569 respectively). The ratio of pregnancies from right-sided ovulation (approximately 64%) per total number of pregnancies was higher than that of right-sided ovulation (approximately 55%) during non-pregnant cycles (P: < 0.0001). The implantation rate in right-sided ovulation seemed to be higher than in left-sided one, since IVF data showed a lower frequency (P: = 0.03) of pre-embryo formation from right-sided ovulation than left-sided. Mid-luteal serum oestradiol and testosterone were higher (P: < 0.05) in right-sided ovulation than left-sided. Taken together, in both fertile and infertile women the fertility potential of oocytes from the right ovary surpasses that of the left ovary.

Relationships between follicular fluid steroid hormone concentrations, oocyte maturity, in vitro fertilization and embryonic development in the rhesus monkey

Oocytes and matched samples of follicular fluid (FF) were obtained from 70 follicles of five rhesus monkeys stimulated with either pregnant mare serum gonadotropin or human menopausal gonadotropin. Follicular aspiration was performed 30-32 h after human chorionic gonadotropin administration. The concentrations of estradiol (E2), progesterone (P), testosterone (T), and dihydrotestosterone (DHT) in FF were measured. Twenty-six percent of oocytes were classified as mature (M), 41% matured in vitro (Miv), 13% were dysmature, and 20% atretic. M oocytes were associated with significantly higher levels of P and a higher P:E2 ratio. There were no differences in hormone levels associated with fertilized and nonfertilized oocytes. Thirty-five embryos developed to the six- to eight-cell stage in vitro, of which 13 exhibited optimal cleavage rates. Significantly lower levels of E2 and higher P:E2 ratios were associated with the more rapidly cleaving embryos. Proportionally more embryos showing optimal cleavage rates developed from M compared to Miv oocytes, and only embryos derived from M oocytes developed to blastocysts in culture. Optimal cleavage rates to the six- to eight-cell stage in vitro, rather than fertilization rates, are a better indicator of (subsequent) developmental capacity, and, in this study, embryonic development was closely associated with the maturity of the oocyte at recovery.

Diminished steroidogenic response of hamster granulosa cells to estrogen in vitro

We have previously demonstrated that estrogen can exert inhibitory or atretogenic effects on the ovaries of both rats and rhesus monkeys in vivo. This study was designed to test whether the hamster (Mesocricetus auratus) is an appropriate model in which to test the effects of estrogens (diethylstilbestrol and estradiol-17 beta) on steroid accumulation by ovarian granulosa cells in vitro, and whether the effects are similar to those demonstrated for other species in vivo. Immature female hamsters were injected with pregnant mare's serum gonadotropin at 28 to 30 days of age. Animals were sacrificed and follicular contents aspirated three days later. Granulosa cells were either left untreated or treated with diethylstilbestrol or estradiol (1 X 10(-7) M) in vitro for 72 h in the presence of androstenedione (1 X 10(-7) M, and in the presence or absence of serum (10%) or human follicle-stimulating hormone (20 ng/ml), and long-term accumulation of estrogen and progesterone was determined. Diethylstilbestrol inhibited accumulation of estrogen regardless of the presence or absence of follicle-stimulating hormone. In contrast, only estradiol plus follicle-stimulating hormone augmented accumulation of progesterone by granulosa cells. These findings that estrogen can be non-stimulatory or inhibitory to function of granulosa cells in vitro parallel those shown in vivo. Our experimental approach may therefore represent an appropriate model for study of the direct effects of estradiol on the function of granulosa cells.

Effect of repeated laparoscopic surgery on the bovine estrous cycle

The effects of repeated laparoscopic surgery on the length of the bovine estrous cycle, estrus, ovulation and corpus luteum function were determined after one estrous cycle of normal duration (18 to 24 days). Five, Angus x Hereford cows were subjected to laparoscopy on days 5, 13, 18 and 20 (estrus = day 0) of the subsequent cycle. Blood was collected daily during the cycle in which laparoscopy was performed (surgical cycle) and during the next cycle (postsurgical cycle). Lengths of the surgical and postsurgical cycles (22.3 +/- .5 days and 21.5 +/- .6 days, respectively) did not differ (P>.05) from that of the presurgical cycle (21.8 +/- .2 days). Average concentrations (ng/ml) of LH and progesterone in serum were similar during the surgical and postsurgical cycles (1.2 +/- .1, 2.2 +/- .2 vs 1.3 +/- .2 and 2.3 +/- .1). Progesterone concentrations remained above 1 ng/ml for 17 and 16 days during the surgical and postsurgical cycles, respectively. A pre-ovulatory rise in LH, along with estrus and ovulation was confirmed in all animals. Follicular development, characterized by follicular volume, increased progressively from days 5 to 20, with the largest increase occurring between days 13 and 18. These results indicate that laparoscopy, used at the times and frequency specified, does not alter reproductive function of cyclic cows and can provide information on ovarian activity.

Serum progesterone and corpus luteum function in pregnant pigtailed monkeys (Macaca nemestrina)

Corpus luteum (CL) function and control during pregnancy and early lactation in the pigtailed macaque was investigated. Peripheral concentrations of progesterone (P) on day 10 of pregnancy were 12.98 +/- 2.21 ng/ml and decreased progressively to 7.96 +/- 1.27 ng/ml by day 21 of pregnancy. The concentration of P increased around day 27 of gestation and reached peak levels of 18.48 +/- 2.45 ng/ml on day 37, thereafter gradually decreasing to a nadir at about midgestation. Ten days before parturition P concentrations increased again (P < 0.05). Concentrations of P decreased from 6.62 +/- 1.48 ng/ml on the day of delivery to 2.16 +/- 0.43 ng/ml on day 2 of lactation and remained low thereafter. Ovariectomy on day 35 did not affect the normal course of gestation or the patterns of P secretion during pregnancy. However, in these ovariectomized animals, in spite of suckling, P was not detectable after parturition. In intact monkeys, serum concentrations of P in the utero-ovarian vein at days 80 and 159 of pregnancy were higher relative to the uterine vein. Incubation studies utilizing 3H-cholesterol as a substrate revealed that the CL were capable of synthesizing P on days 35 and 159 of gestation. Histologically, the CL contained active luteal cells at late pregnancy. Low serum concentrations of chorionic gonadotropin were detected on day 10 of gestation; concentrations of this hormone reached high levels between days 18 and 24 and the titers were nondetectable after day 40 of pregnancy. Luteinizing hormone was present in constant amounts in the circulation during pregnancy and lactation. These data suggest that the CL of pregnancy in the pigtailed monkey is functional or capable of functioning during various stages of pregnancy. However, the fetoplacental unit is the primary source of P during the latter 4.5 months of gestation. As in other primates, a functional CL is not required for maintenance of pregnancy after implantation nor for lactation. Thus, the physiological significance of CL function during pregnancy is unclear.