BACKGROUND The use of oral progestin has been shown to effectively prevent luteining hormone (LH) surge during ovarian stimulation with daily human menopausal gonadotropin injections. This study was aimed to investigate the efficacy of long-acting follicle stimulating hormone (long-acting FSH; corifollitropin alfa, Elonva®) use in progestin-primed ovarian stimulation for normal and high respond...

In a dose dependent manner, LY 87130, an inhibitor of adrenaline synthesis in the rat brain, either shifts the pro-oestrous surges of luteinizing hormone and follicle stimulating hormone from the late afternoon to the middle of the night or blocks any occurrence of the surges and prevents ovulation. Because the pulsatile release of LH is also blocked by LY 87130, it is proposed that the role of...

Molinate, a thiocarbamate herbicide, has been reported to impair reproductive capability in the male rat and alter pregnancy outcome in a two-generation study. Published data are lacking on the effects of acute exposure to molinate in the female. Based on this work and our previous observations with related dithiocarbamate compounds, we hypothesized that a single exposure to molinate during the...

We have investigated the role of mu- and kappa-opioid receptors in the central control of preovulatory LH and FSH release in the proestrous rat. Animals were anesthetized with chloral hydrate at 14:00 h on proestrus day. Following femoral artery cannulation, they were mounted in a stereotaxic apparatus. Morphine and U-50488H (benzene-acetamide methane sulphonate) were infused intracerebroventri...

Arif Siddiqui, Saeeda Shaharyar Department of Biological and Biomedical Sciences, The Aga Khan University, Karachi. Pakistan Background: The present study was designed to inves tigate the role of the 5-HT7 receptors in lordosis and release of LH and compare the lordotic responses with 5-HT1A agent. Methods: Ovariectomised but oestradiol benzoate (OB) (10 ug) for 48 h plus by progesterone (0.5 m...

To examine the role of the gamma-aminobutyric acid-A receptor-mediated system in the timing of the proestrous LH surge, we observed the free running activity rhythm and the timing of the LH surge simultaneously in blinded cycling female rats. Blood samples were obtained from unanesthetized freely moving rats through an intraatrial cannula. Five hours after the activity offset on the day of proe...

In postpartum cows, ovulatory follicle size at time of insemination (GnRH/TAI) influenced pregnancy rates following TAI, but had no effect on pregnancy rates when cows spontaneously ovulated. Furthermore, cows that exhibited estrus (± 24 h of GnRH/TAI) had higher pregnancy rates compared to cows not in estrus. The objective was to assess the relationship between ovulatory follicle size and estr...

Five experiments were conducted to test the hypothesis that psychosocial stress interferes with the estrous cycle of sheep. In experiment 1, ewes were repeatedly isolated during the follicular phase. Timing, amplitude, and duration of the preovulatory luteinizing hormone (LH) surge were not affected. In experiment 2, follicular-phase ewes were subjected twice to a "layered stress" paradigm cons...

Twenty-four adult female Sprague-Dawley rats (3 from each of 8 litters), showing 4-day cycles, were used in the present study. Aqueous extracts of pools of 6 pituitary glands in each cycle date were fractionated with a column isoelectrofocusing (IEF) technique, pH range of 3.5-10. Biological and immunological LH activities were determined by an in vitro bioassay and a radioimmunoassay, respecti...

Plasma hormonal changes were analysed in patients with hyperprolactinemia who conceived following Bromocriptine therapy. Following the administration of HMG-HCG and Bromocriptine, serial plasma samples were collected from the cases. Plasma levels of FSH, LH, prolactin (PRL), estrone (E1), estradiol (E2), 17-hydroxyprogesterone (17-P), 20 alpha-dihydroprogesterone (20 alpha-P), progesterone (P) ...