There are two forms of ovulation: spontaneous and induced. As copulation triggers ovulation for induced ovulators, males can predict the timing of ovulation and may have greater paternity monopolization than spontaneous ovulators. However, this prediction has never, to my knowledge, been tested. Using a cross-species comparison I examined the percentage of offspring sired within a litter (singl...

Females in species that produce broods of multiple offspring need to partition resources among simultaneously growing ova, embryos or neonates. In birds, the duration of growth of a single egg exceeds the ovulation interval, and when maternal resources are limited, a temporal overlap among several developing follicles in the ovary might result in a trade-off of resources among them. We studied ...

This study reviewed the protocols for ovulation induction in sows by human chorionic gonadotropin (hCG) and gonadotropin releasing hormone (GnRH). In pigs, it was documented that ovulation usually occurred about 70% of the way through oestrus. However, the duration of oestrus in sows highly varies, producing difficulty in performing artificial insemination (AI) in sows at optimal time. In pract...

Ovulation is an essential physiological process in sexual reproduction; however, the underlying cellular mechanisms are poorly understood. We have previously shown that OAMB, a Drosophila G-protein-coupled receptor for octopamine (the insect counterpart of mammalian norepinephrine), is required for ovulation induced upon mating. OAMB is expressed in the nervous and reproductive systems and has ...

Repeated measures of ovulation rate on puberal heifers should be an effective way to select for increased twinning rate. A reliable estimate of the genetic correlation between ovulation and twinning rates is needed to implement such selection and to predict its efficiency. Restricted maximum likelihood was used to estimate genetic correlations from subsets of data collected from the twinning pr...

gonad anterior pituitary estrogen progesterone (Litter er size plays a major role in the economics of swine production. Even modest increases in average litter size can have considerable effects on overall profitability. Two major components of litter size, 1) ovulation rate, and 2) embryonic survival, have been used in a selection index project ongoing for several generations at the University...

Endothelin-2 (EDN2), a potent vasoconstrictive peptide, is transiently produced by periovulatory follicles at the time of ovulation when corpus luteum (CL) formation begins. EDN2 induces contraction of ovarian smooth muscles ex vivo via an endothelin receptor A-mediated pathway. In this study, we aimed to determine if EDN2 is required for normal ovulation and subsequent CL formation in?vivo. In...

Proper coordination of oogenesis, ovulation, and fertilization is essential for successful reproduction. In Caenorhabditis elegans, a strong loss-of-function mutation in dpl-1, which encodes a subunit of the E2F heterodimeric transcription factor EFL-1/DPL-1, causes severe defects during ovulation and fertilization. Here we demonstrate that the somatic gonad structure and sheath cell contractio...

BACKGROUND Ovarian epithelial dysplasia was first described after prophylactic oophorectomies for genetic risk. Ovarian stimulation has been considered as a risk factor of ovarian cancer by Fathalla's incessant ovulation theory. In this study, we have investigated the risk of ovarian dysplasia after ovulation induction. METHODS We reviewed 99 oophorectomies or cystectomies between 1990 and 20...

BACKGROUND Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in females of reproductive age. Insulin resistance is a frequent metabolic disturbance in PCOS. Vitamin D deficiency is a common problem. Accumulating evidence suggests that vitamin D has a role on insulin sensitivity so may contribute to reduction of hyperandrogenemia. OBJECTIVE The aim was to determine the eff...