Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxytocin (OT) and its mRNA are expressed at very low levels in granulosa cells from bovine preovulatory follicles isolated before the LH/FSH surge and increase dramatically between the surge and ovulation. We have shown previously that OT stimulates progesterone secretion by granulosa cells obtained before, but not after the gonadotropin surge, suggesting that OT may be involved in the follicular/luteal phase shift in steroidogenesis from estradiol/androgen to progesterone. One objective of this study was to determine if OT affects estradiol as well as progesterone production by utilizing culture conditions that maintain estradiol secretion in vitro. A second objective was to determine if OT regulates steroidogenesis by effects on the levels of mRNA for the steroidogenic enzymes involved in progesterone synthesis, cytochrome P450 side-chain cleavage (P450scc) and 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), or in estradiol production, cytochrome P450 aromatase (P450arom). Granulosa cells were isolated from bovine preovulatory follicles and cultured for 3 days with or without OT in medium supplemented with either insulin (1 microgram/ml) + 1% fetal calf serum (FCS), which maintains basal estradiol secretion, or low doses of FSH (1 and 2 ng/ml) + 1% FCS, a culture condition that maximizes effects of FSH on estradiol secretion. After the first day of culture, OT stimulated progesterone (P < 0.01) and inhibited estradiol production (P < 0.01) in both control and FSH-treated cultures. In contrast, OT had only a small stimulatory effect on the levels of mRNA for P450scc and 3 beta-HSD and no effect on mRNA for P450arom. These findings suggest that: (1) OT plays an autocrine role in regulating the follicular luteal phase shift in steroidogenesis by both increasing progesterone and inhibiting estradiol production and (2) the differential effects of OT on steroid production are not mediated primarily by effects on levels of mRNA for steroidogenic enzymes.
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PMID:Differential effects of oxytocin on steroid production by bovine granulosa cells. 864 19

Early porcine conceptus development is characterized by rapid trophoblastic elongation between Days 11 and 12 of pregnancy, a period of embryonic loss in the pig. Growth factors and steroids secreted by the conceptus and uterus, as well as ligand receptors produced by the conceptus, are thought to regulate trophoblastic elongation. Therefore, the objectives of this study were to characterize conceptus gene expression for the steroidogenic enzymes 17alpha-hydroxylase and aromatase and the mesodermal marker brachyury, as well as the expression of receptors for fibronectin (integrin beta-1), progesterone, estrogen, oxytocin, prostaglandin F2alpha, and leukemia inhibitory factor (LIF), prior to and during trophoblastic elongation. Total RNA was extracted from individual conceptuses from Day 10 to Day 12 of pregnancy. Gene expression was determined by reverse transcription polymerase chain reaction on conceptuses having 2- to 4-, 5-, 6-, 7-, 8-, 9-, and 10- to 12-mm spherical, 13- to 25-mm tubular, and > 100-mm filamentous morphologies. There was a stage of development effect on both 17alpha-hydroxylase (p < 0.001) and aromatase (p < 0.003) gene expression. Initial 17alpha-hydroxylase gene expression was detected in early spherical conceptuses (2-4 mm), increasing abruptly through to 7-mm conceptuses. Aromatase gene expression increased dramatically in 6- to 7-mm conceptuses, with increased expression throughout development. Gene expression for LIF receptor (LIFR) (p < 0.02) was similar to that for 17alpha-hydroxylase, while brachyury gene expression began in 6-mm conceptuses and increased (p < 0.001) throughout development. Integrin beta-1 was expressed at all stages of development. Conceptus gene expression was not detected for progesterone, estrogen, oxytocin, and prostaglandin F2alpha receptors. Prior to elongation, dynamic changes in gene expression are occurring that appear to be associated with estrogen production and preparation of the conceptuses for elongation. LIFR expression is highly associated with steroidogenic enzyme production with an initial peak preceding rapid trophoblastic elongation, suggesting that LIF may be involved in early conceptus development in the pig.
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PMID:Ontogeny of elongation and gene expression in the early developing porcine conceptus. 936 95

The aim of this study was to investigate the expression of cytochrome P450 aromatase (aromatase) mRNA, its activity, and estradiol-17beta (estradiol) secretion in bovine corpus luteum (CL) during the estrous cycle. Expression of aromatase mRNA was examined in CL at the early, mid, late, and regressed luteal stages by using a reverse transcription-polymerase chain reaction. Aromatase mRNA was detected in all luteal stages examined, although aromatase expression was significantly lower during the early and regressed luteal phases compared to the mid and late luteal phases. Moreover, cultured midluteal cells clearly converted exogenous [(3)H]androstenedione into estradiol, and an aromatase inhibitor significantly inhibited this conversion. To characterize the local release of estradiol within the CL during the estrous cycle, an in vitro microdialysis system (MDS) of CL was conducted. Estradiol in MDS perfusate was confirmed by a reverse-phase high-performance liquid chromatography in combination with enzyme immunoassays. Basal release of estradiol from microdialyzed CL did not change during the estrous cycle. Additionally, when freshly prepared midluteal cells were exposed to estradiol (10(-14) to 10(-9) M), estradiol stimulated prostaglandin (PG) F(2alpha) secretion (P < 0.05), although it did not affect progesterone and oxytocin secretion. The overall results indicate that estradiol is produced locally in bovine CL throughout the estrous cycle, and they suggest that estradiol plays a role in regulating PGF(2alpha) production in CL as an autocrine/paracrine factor.
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PMID:Estradiol-17beta is produced in bovine corpus luteum. 1171 22

With combined immunoperoxidase and immunofluorescence, we observed colocalization of cytochrome P450 aromatase with the posterior lobe peptide oxytocin and its associated neurophysin 1 in adult male rats. P450 was most abundant in the anterior hypothalamus. Colocalization of OT with P450 was observed in the preoptic region, the periventricular nucleus of the hypothalamus, the lateral subcommissural nucleus, and in the zona incerta. Magnocellular perikarya in the supraoptic and in the paraventricular nuclei contained only occasionally both antigens. P450 immunostaining overlapped to a great extent with known estrogen target regions. Oxytocinergic functions are controlled by estradiol while androgen receptors are mostly absent in neuroendocrine hypothalamic nuclei. Our findings suggest that systemic androgens may be aromatized to estrogens in male oxytocinergic neurons linked to the limbic system.
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PMID:Colocalization of p450 aromatase and oxytocin immunostaining in the rat hypothalamus. 2322 40

Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide that was isolated from the brains of Japanese quail in 2000, which inhibited luteinizing hormone release from the anterior pituitary gland. Here, we summarize the following fifteen years of researches that investigated on the mechanism of GnIH actions at molecular, cellular, morphological, physiological, and behavioral levels. The unique molecular structure of GnIH peptide is in its LPXRFamide (X=L or Q) motif at its C-terminal. The primary receptor for GnIH is GPR147. The cell signaling pathway triggered by GnIH is initiated by inhibiting adenylate cyclase and decreasing cAMP production in the target cell. GnIH neurons regulate not only gonadotropin synthesis and release in the pituitary, but also regulate various neurons in the brain, such as GnRH1, GnRH2, dopamine, POMC, NPY, orexin, MCH, CRH, oxytocin, and kisspeptin neurons. GnIH and GPR147 are also expressed in gonads and they may regulate steroidogenesis and germ cell maturation in an autocrine/paracrine manner. GnIH regulates reproductive development and activity. In female mammals, GnIH may regulate estrous or menstrual cycle. GnIH is also involved in the regulation of seasonal reproduction, but GnIH may finely tune reproductive activities in the breeding seasons. It is involved in stress responses not only in the brain but also in gonads. GnIH may inhibit male socio-sexual behavior by stimulating the activity of cytochrome P450 aromatase in the brain and stimulates feeding behavior by modulating the activities of hypothalamic and central amygdala neurons.
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PMID:Molecular, cellular, morphological, physiological and behavioral aspects of gonadotropin-inhibitory hormone. 2640 90