Kiss1 expression in the hypothalamic arcuate nucleus is lower in dairy cows of reduced fertility

We tested the hypothesis that divergent genetic merit for fertility of dairy cows is due to aberrant reproductive neuroendocrine function. The kisspeptin status of non-pregnant cows of either positive (POS) or negative (NEG) breeding values for fertility was studied in 3 groups (n = 8), based on their previous post-partum period: POS cows which had spontaneous ovarian cycles (POS-CYC) and NEG cows which either cycled (NEG-CYC) or did not cycle (NEG-NONCYC). Ovarian cycles were synchronized, blood samples were taken to define endocrine status and the animals were slaughtered in an artificial follicular phase. The brains and the pituitary glands were collected for quantitative polymerase chain reaction (qPCR) and in situ hybridisation (ISH) of hypothalamic GNRH1, Kiss1, TAC3 and PDYN and pituitary expression of LHB and FSHB. Gonadotropin releasing hormone (GnRH) and kisspeptin levels were quantified in snap frozen median eminentes (ME). GNRH1 expression and GnRH levels in the ME were similar across groups. Kiss1 expression in the preoptic area of the hypothalamus was also similar across groups, but Kiss1 in the arcuate nucleus was almost 2-fold higher in POS-CYC cows than in NEG groups. TAC3 expression was higher in POS-CYC cows. The number of pituitary gonadotropes and the level of expression of LHB and FSHB was similar across groups. We conclude that the lower levels of Kiss1 and TAC3 in NEG cows with low fertility status, and may lead to deficient GnRH and gonadotropin secretion.

The miR-424/503 cluster modulates Wnt/β-catenin signaling in the mammary epithelium by regulating the expression of the LRP6 co-receptor

During the female lifetime, the enlargement of the epithelial compartment dictated by the ovarian cycles is supported by a transient increase in the MaSC population. Notably, activation of Wnt/β-catenin signaling is an important trigger for MaSC expansion. Here, we report that the miR-424/503 cluster is a novel modulator of canonical Wnt-signaling in the mammary epithelium that exerts its function by targeting the LRP6 co-receptor. Additionally, we show that the loss of this microRNA cluster is associated with breast cancers possessing high levels of Wnt/β-catenin signaling.

Coital Frequency and the Probability of Pregnancy in Couples Trying to Conceive Their First Child: A Prospective Cohort Study in Japan

Background: Low fertility persists but remains unexplained in Japan. We examined whether the probability of pregnancy was influenced by coital frequency, age, reproductive age (assessed by antimüllerian hormone, AMH), and BMI. Methods: We established a two-year prospective study with a sample of hormonally monitored Japanese women aged 23–34 years wanting to conceive their first child. For a maximum of 24 weeks participants recorded menstrual bleeding, sexual intercourse, ovulation, and pregnancy. Additional information on pregnancy and infertility treatment was collected one and two years after intake. Results: The natural conception rate and coital frequency were both low in this sample. Among 80 participants, 44% (35) naturally conceived in 24 weeks. After two years, 74% (59) of women had delivered or were currently pregnant, 50% (40) due to natural and 24% (19) due to assisted conception, and 5% (4) were lost to follow-up. By two years, 56% (45) of women had sought fertility treatment. In 18% (58/319) of the observed ovarian cycles across 24 weeks there was no intercourse in a fertile period. Higher coital frequency at intake was associated with increased probability of conception by 24 weeks of follow-up (OR 1.23, 95%CI 1.02, 1.47). Chronological age, reproductive age, and BMI were not associated with the probability of pregnancy at 24 weeks. Conclusions: Our results suggest that first, natural conception rates could potentially increase with more frequent and well timed intercourse, and second that further work is needed to understand why even in a motivated sample of women monitoring their fertile periods, both the conception and coitus rates were low.

SEX HORMONES AND ARTHRITIS IN A LONG-LIVED ANIMAL MODEL, THE ELEPHANT

Arthritis affects women more so than men, particularly after menopause. Sex hormones may play a role in arthritis development, yet this is still unclear. Elephants have a similar lifespan to humans and develop arthritis and joint issues (musculoskeletal impairments (MI)), but do not undergo menopause. Interestingly, many female zoo elephants do not exhibit normal ovarian cycles, closely resembling that in post-menopausal women. Objectives: 1) examine ovarian cyclicity status with MI (Asians: N=84; Africans: N=83); 2) determine whether gonadotropin and sex hormones are reduced in cycling elephants with MI (Asians: N=16; Africans: N=26); and 3) evaluate whether serum CTXI, a marker of type 1 collage degradation, is associated with MI in elephants (Asians: N=40; Africans: N=32). We used longitudinal serum and health data on ovarian cycling and non-cycling zoo African and Asian elephants with and without MI. Serum progestagen, leutinizing hormone, follicle stimulating hormone, and CTXI concentrations were measured. Cyclicity status was based on progestagen patterns. Zoo veterinarians classified the elephant with MI based on clinical exams and observations. In both Asian and African elephants, MI was significantly associated with cyclicity status (P=0.015, 0.032, respectively), but not independent of age (P=0.251, 0.091, respectively). There were no significant differences in any hormone concentration, during either the luteal or follicular phase, between elephants with or without MI (P>0.135). There were no significant differences in CTXI concentrations between age- and cycling-matched elephants with and without MI (P>0.957). Preliminary results do not provide compelling evidence that gonadotropin and sex hormones influence MI development in elephants.

Uterine Involution and Ovarian Activity in Postpartum Holstein Dairy Cows. A Review

Following parturition in the cow, there is a significant period of sexual quiescence of variable length. This period of reproductive quiescence was found to be longer in suckling or intensively milked animals.This acyclic period is generally considered as the postpartum anoestrous period. The postpartum period constitutes an important period in the reproductive life of dairy cows because of its enormous influence upon subsequent fertility. The entire postpartum period, puerperium, is defined as the period from parturition until the genital organs return to its normal physiological and histological condition, as in normal non-gravid state. They added that any extension of the puerperium in cows might have a detrimental effect on the reproductive performance of the individual animal. Thus, the main determinant of this period is essentially dependent on the resumption of normal ovarian cycles, the manifestation of estrus behaviour and conception following insemination.

Ovarian and thyroid activity of the Lacaune ewes breed during the year in Greece

Ovarian and thyroid activity was studied in 10 ewes of Lacuane breed during one year. Ewes were maintained separately from rams and were fed. The aim of the study was to determine the duration of the anestrus period. Blood samples were collected weekly for the determination of progesterone levels. Thyroxine levels were also determined. Progesterone concentrations > 1 ng/ml were considered as indicative of ovulation, whereas levels between 0.5-0.9 ng/ml as indicative of follicle luteinizations or short lived corpus luteum. Two ewes showed persistent corpus luteum which regressed in deep anestrus period. The first ovulation occurred on 18th August ±10 days. The duration of the breeding season (the interval from the first to the last ovulation) was estimated to be 158 ± 8 days and the number of ovarian cycles during this period was 9.0 ± 0.6 per ewe. A significant correlation was observed between the time of the last ovulation and the duration of the breeding season, (Y=l4l.4+0.96X, r2 = 0.71, P<0.01). Serum thyroxine levels in every fifteen days samples fluctuate from 47 ± 4 during the first half of August to 82 ± 5 during the second half of December. Mean thyroxine levels during the time of increasing daylength (23rd December to 22nd June) were 71.2 ± 2 ng/ml and during that of decreasing daylength (23rd June to 22nd December) 59.4 ± 3 ng/ml, (p<0.001). In conclusion, this study showed that the ewes of the Lacaune breed exhibit a long anestrous period compared to the indigenous Greek breeds. Hormonal control of estrus is necessary for the out-of season lambing. Finally, thyroid function shows a significant seasonality, as has been demonstrated in all other breeds of sheep studied so far.