The present study was conducted to evaluate the endocrinological effects of the pituitary on luteal maintenance and regression in the cyclic golden hamster (Mesocritus auratus). After hypophysectomy (Hypox) at 0900 h on day 1 of the estrous cycle (the day of ovulation), the animals received injection of prolactin (PRL) or PRL plus equine chorionic gonadotropin (eCG). They were decapitated at 15...

Antioxidant enzymes seem to play roles in controlling the luteal function and the luteolytic action of prostaglandin F2α (PGF). The aim of this study was to clarify the roles of catalase (CAT) and glutathione peroxidase (GPx) in the luteolytic action of PGF in both corpus luteum (CL) and cultured luteal cells. Corpora lutea were collected at the early (days 2-3), developing (days 5-6), mid (day...

A study was conducted to determine whether bovine blastocyst-stage embryos and trophoblastic vesicles stimulate the production of progesterone in bovine luteal cells during incubation in vitro. The effects of co-incubation of these embryos and vesicles with uterine endometrial tissue on progesterone production was also investigated. Bovine small and large luteal cells were obtained on day 12 of...

The expression of the steroidogenic acute regulatory protein (StAR) in the human corpus luteum (CL) was examined throughout the luteal phase. The primary 1.6-kb StAR transcript was in greater abundance in early (3.1-fold) and mid (2.2-fold) luteal phase CL compared with late luteal phase CL. The larger StAR transcript (4.4 kb) was found in early and midluteal phase CL, but was not detected in l...

The first report of the combined use of pituitary suppression and ovarian hyperstimulation in invitro fertilization (IVF) and embryo transfer programmes was published in 1984 (1). Since then, the advantages of gonadotrophin hormonereleasing hormone analogues (GnRHa) have been well documented; the cancellation rate has been decreased through the prevention of premature luteinizing hormone (LH) s...

background: controlled ovarian stimulation combined with intra uterine insemination (iui) is a convenient treatment of infertility with a success rate of 11%. the clinical observation and pattern of progesterone secretion in this method is suggestive of luteal phase defect and postulated as an implicating factor of treatment failure. objective: to investigate the efficacy of luteal phase suppor...

the aim of this study was to evaluate the defense cells changes of cervical mucous during follicular and luteal phases of estrus cycle in river buffalo. reproductive organs of the adult and apparently healthy female buffaloes were collected from the slaughterhouse. by visual investigation of both the ovaries for presence of corpus luteum and growing follicles, the luteal and follicular phase of...

Experiments were conducted to identify neurons in the bovine brain that express the LHRH gene and to determine whether LHRH mRNA levels are influenced by the ovaries. Two groups of postpubertal heifers were utilized: heifers killed during the mid-luteal phase of the estrous cycle (LUTEAL, n = 5) and heifers killed 14-16 wk following ovariectomy (OVX, n = 5). In situ hybridization was performed ...

The causes of luteal phase progesterone deficiency in polycystic ovary syndrome (PCOS) are not known. To determine the possible involvement of hyperinsulinemia in luteal phase progesterone deficiency in women with PCOS, we examined the relationship between progesterone, luteinizing hormone (LH) and insulin during the luteal phase and studied the effect of metformin on luteal progesterone levels...