In vitro fertilization (IVF) and embryo transfer and intracytoplasmic sperm injection (ICSI) have allowed millions of infertile couples to achieve pregnancy. As an essential part of IVF/ICSI enabling the retrieval of a high number of oocytes in one cycle, controlled ovarian stimulation (COS) treatment mainly composes of the standard long gonadotrophin-releasing hormone agonist (GnRH-a) protocol and the gonadotrophin-releasing hormone antagonist (GnRH-ant) protocol. However, the effectiveness of GnRH-ant protocol is still debated because of inconsistent conclusions and insufficient subgroup analyses. This systematic review and meta-analysis included a total of 52 studies, encompassing 5193 participants in the GnRH-ant group and 4757 in the GnRH-a group. The findings of this study revealed that the GnRH-ant protocol is comparable with the long GnRH-a protocol when considering live birth as the primary outcome, and it is a favourable protocol with evidence reducing the incidence of ovarian hyperstimulation syndrome in women undergoing IVF/ICSI, especially in women with polycystic ovary syndrome. Further research is needed to compare the subsequent cumulative live birth rate between the two protocols among the general and poor ovarian response patients since those patients have a lower clinical pregnancy rate, fewer oocytes retrieved or fewer high-grade embryos in the GnRH-ant protocol.

GPR120 is implicated in the regulation of glucose and lipid metabolism, and insulin resistance. In the current study, we aimed to investigate the role of GPR120 in polycystic ovary syndrome (PCOS). With the adoption of dehydroepiandrosterone, a rat model was established to simulate PCOS in vitro. mRNA and protein expression levels of GPR120 were measured using RT-qPCR and western blot, respectively. In addition, expression levels of testosterone, estradiol, luteinizing hormone and follicle-stimulating hormone, serum total cholesterol and triglyceride were assessed using the corresponding kits. Moreover, haematoxylin and eosin staining was used to detect pathological changes in ovary or liver and oil red staining was utilized to evaluate lipid accumulation. In the present study, GPR120 was downregulated in plasma, liver and ovary in the PCOS rat model. In addition, the GPR120 agonist regulated lipid metabolism in the liver and weight in the PCOS rat model. Furthermore, the GPR120 agonist decreased insulin resistance in the PCOS rat model but improved the ovarian function. It is suggested that GPR120 plays a vital role in suppressing insulin resistance, regulating ovary function and decreasing lipid accumulation in the liver, demonstrating that targeting GPR120 could be an effective method for the improvement of PCOS.

The results of epidemiological studies involving n-3 PUFA and polycystic ovary syndrome (PCOS) are scarce. This matched case–control study assessed the associations between n-3 PUFA and PCOS prevalence in 325 pairs of PCOS cases and healthy controls. Dietary information was assessed using a 102-item FFQ. Fatty acids in serum phospholipids were measured with a GC method. We found that n-3 PUFA in serum phospholipids were inversely associated with PCOS prevalence, including total, long-chain and individual PUFA (e.g. docosapentaenoic acid (DPA), EPA and DHA). Compared with the lowest tertile (T1), the adjusted OR and their 95% CI for the highest tertile (T3) were 0·63 (0·40, 0·93) for total n-3 PUFA, 0·60 (0·38, 0·92) for long-chain n-3 PUFA, 0·68 (0·45, 1·01) for DHA, 0·70 (0·45, 1·05) for EPA and 0·72 (0·45, 1·08) for DPA. For dietary intake of n-3 PUFA, significant inverse associations were found only for long-chain n-3 PUFA (Ptrend = 0·001), EPA (Ptrend = 0·047) and DHA (Ptrend = 0·030). Both dietary and serum n-3 PUFA, mainly EPA and DPA, were negatively correlated with PCOS-related parameters, such as BMI, fasting insulin, total testosterone and high-sensitivity C-reactive protein, but positively correlated with follicle-stimulating hormone and sex hormone-binding globulin. These results indicated inverse associations between n-3 PUFA, especially long-chain n-3 PUFA, and PCOS prevalence. Higher intakes of n-3 PUFA might be considered a protective factor for PCOS among Chinese females.

Fifteen nulliparous and nine multiparous Serrana goats were used, through two successive oestrous cycles, in order to characterize their ovulation time with regard to the number of ovulations after induced and natural oestrus during the breeding season. The onset of oestrus was detected by the amount of vasectomized bucks after oestrus synchronization with prostaglandin, given 10 days apart, and in the following two expected natural oestrus. The preovulatory LH peak was determined from blood samples collected 0, 4, 8, 12, 16, 20 and 24 h after onset of oestrus. A transrectal ovarian ultrasound scanning was performed 20, 24, 28, 32, 36, 40, 44 and 60 h after onset of oestrus, for the detection of ovulations by means of the disappearance of large follicles (>4 to 5 mm). Single ovulations were observed in 76% of oestrous periods in nulliparous goats and in 18% of nulliparous goats. The onset of oestrus to LH peak interval was lower in nulliparous (12.1 ± 0.9 h, n = 38) than in multiparous (15.6 ± 1.0 h, n = 22, P < 0.05) goats with no oestrus interaction effects (P > 0.05). The LH peak to first ovulation interval was higher after natural (18.9 ± 0.7 h, n = 36) than after induced (15.8 ± 1.2 h, n = 24, P < 0.05) oestrus. The onset of oestrus to total ovulation interval was influenced by parity (P < 0.01) and oestrus type (P < 0.05) with a length of 30.1 ± 1.1 h (n = 15) and 33.4 ± 1.5 h (n = 9) for induced oestrus of nulliparous and multiparous goats, respectively, and 32.5 ± 1.0 h (n = 23) and 36.5 ± 1.1 h (n = 13) for natural oestrus of nulliparous and multiparous goats, respectively. The onset of oestrus to first ovulation interval was not influenced by parity, but an interval of 8.0 ± 1.6 h was observed between the first and second ovulations in polyovulatory oestrus. Consequently, nulliparous goats that are predominantly monovular ovulate earlier than multiparous goats that are predominantly polyovulatory. In conclusion, significant differences occurred in the number and time of ovulations between nulliparous and multiparous goats. More research is necessary for a deeper understanding of the mechanisms regulating monovularory and polyovulatory oestrous cycles regarding the parity of goats.

The present study was designed to elucidate the mechanisms accounting for disruption of the normal function of the testis exposed to various levels of Pb. Three different doses of Pb (10, 50, 200mg Pb/kg body weight per d) were given orally to male Portan rats (groups 2, 3, 4). Zn (1mg Zn/kg body weight per d) was also given with Pb (50mg Pb/kg body weight per d) in group 5. Treatments continued for 3 months. Plasma luteinizing hormone and follicle-stimulating hormone concentrations were found to be decreased in Pb-exposed rats. This was in turn reflected in the appreciable decline in fertility status. In cell kinetic studies, significant declines in various cell populations (preleptotene, pachytene, young (step 7) spermatids and mature (step 19) spermatids) were seen. However, in group 5 after Zn supplementation, hormone levels, cell numbers and fertility status were found to be close to normal. It is concluded that Pb might act at maturation level to cause conspicuous degenerative changes in the testis; Zn supplementation protected against these effects.

Non-reproductive female Damaraland mole-rats Cryptomys damarensis that were caught before a period of good rainfall (during which 90% of the average annual fell) (Group 1), exhibited a significantly lower pituitary sensitivity to gonadotrophin-releasing hormone compared to non-reproductive females (Group 2) caught in the same area, close to the end of the wet period. Group 2 were also significantly heavier than Group 1. Pituitary sensitivity was not significantly correlated to body mass within either group of females, nor within groups of reproductive males and non-reproductive males from a laboratory held colony. This suggests that rainfall may have resulted in the simultaneous, but unrelated, increase in pituitary sensitivity and body mass. Larger size and reduced sexual inhibition assist dispersal and the probability of successful independent reproduction, during periods when environmental constraints on dispersal are relaxed. These findings support the hypothesis that low rainfall may be an important constraint on dispersal and an important factor promoting the evolution of reproductive inhibition, and consequently eusociality, in this species.

Agonistic and sexual interactions as well as plasma bioactive luteinizing hormone (LH) concentrations were monitored in all the adults of two colonies of the naked mole-rat Heterocephalus glaber at three phases in the pregnancy of the breeding female. Blood samples were collected at early (days 1–15), mid (days 30–40) and late (days 55–65) phases of her pregnancy, and the circulating basal plasma LH and the response to administration of 0.1 μg gonadotrophin-releasing hormone (GnRH) were examined. In both colonies it was found that non-breeding males and females showed depressed basal LH concentrations and responses to a GnRH challenge. However, there was considerable variation between individuals, in terms of both basal plasma and post-GnRH concentrations of LH, implying that certain individuals were more suppressed than others. The responses were more pronounced in non-breeding males than in non-breeding females, and this is discussed in light of the reproductive skew occurring within colonies. Few agonistic interactions occurred between the breeding female and the majority of the colony members, and overall, there was no clear relationship between plasma LH and the amount of aggression received from the breeding female. However, in one colony there was a significant positive correlation between basal plasma LH concentrations of non-breeding females and agonistic interactions received by them from the breeding female. In this same colony, older females and older and heavier males received most of the aggression from the breeding female. The second colony did not show this trend, possibly because it had recently lost many large animals during fighting for succession; in this colony sexual interactions were elevated.