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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The levels of nuclear progesterone and estradiol receptors have been followed during the development and decline of deciduomata induced in the uteri of ovariectomised rats. There were broadly 2 phases of deciduomal growth, the first phase being associated with high estrogen nuclear receptor levels per unit DNA. Progesterone nuclear receptor levels did not greatly change (in relation to DNA content) during both phases of full deciduomal development but peak levels were observed on day 5 after decidualization. Alkaline phosphatase activity was maximal by day 3, before peak hormone receptor levels were reached in the nuclei.
Mol Cell Endocrinol 1980 Nov
PMID:Nuclear progesterone and estradiol receptors in deciduomata induced in ovariectomised rats. 743 24

We have used reverse transcription followed by polymerase chain reaction amplification to investigate changes in expression of nerve growth factor (NGF) mRNA in immortalized hippocampal neurons after treatment with the glucocorticoids dexamethasone and corticosterone, the glucocorticoid antagonist RU38486, and the gonadal steroids progesterone and 17-beta oestradiol. We found that NGF mRNA levels rise after application of either dexamethasone or corticosterone, and that this rise is prevented by the antagonist. Thus, neurotrophin expression is modulated by the physiological glucocorticoid and is mediated by type II glucocorticoid receptors. Progesterone has no effect, while 17-beta oestradiol suppresses NGF mRNA in a postnatally-derived cell line but does not change levels in an embryonic line. An increase in neurotrophin expression is therefore not a general response to steroid hormone application, and may be a specific defence against the presence of metabolically endangering glucocorticoids.
Brain Res Mol Brain Res 1995 Jul
PMID:Neurotrophin expression modulated by glucocorticoids and oestrogen in immortalized hippocampal neurons. 747 24

The ability of ovarian steroids to regulate the excitability of hippocampal neurons may be mediated by alterations in the inhibitory activity of GABA. We assessed the ability of estradiol, progesterone, and 3 alpha-OH-5 alpha-pregnan-20-one (3 alpha-OH-DHP; a metabolite of progesterone) to regulate gene expression of selected GABAA receptor subunits (alpha 1, alpha 2, beta 1, beta 2, and gamma 2). Using in situ hybridization, we found that progesterone, or 3 alpha-OH-DHP, suppressed mRNA levels for the alpha 1 subunit in the CA2, CA3, and the dentate gyrus subfields of the hippocampus in animals that were pretreated with estradiol. Progesterone had a more limited effect on the alpha 2 subunit, suppressing mRNA levels in estradiol-primed animals only in the CA3 region. In contrast, progesterone increased mRNA levels for the gamma 2 subunit in the CA1, CA2, and CA3 regions of the hippocampus, but only in animals that were not estradiol-primed. Estradiol alone had no significant effect on the expression of any subunit examined. Beta 1 and beta 2 subunit mRNA levels were not altered by any of the hormones tested. These data support the conclusion that progesterone and its metabolites may regulate excitability of the hippocampus by modulating the GABAA receptor gene expression; these effects of progesterone are dependent upon the circulating levels of estradiol. Alterations in the gene expression of selective subunits may lead to changes in the density of GABAA receptor protein or to changes in receptor subunit composition which might alter receptor sensitivity to activation by GABA or modulators such as the benzodiazepines and convulsants.
Brain Res Mol Brain Res 1995 Sep
PMID:Specific subunit mRNAs of the GABAA receptor are regulated by progesterone in subfields of the hippocampus. 750 Aug 38

The present study tested the hypothesis that hydrogen peroxide (H2O2) inhibits low-density lipoprotein (LDL) uptake and LDL-supported steroidogenesis by luteal cells. LDL uptake: dispersed porcine luteal cells from mid-cycle (days 6-11, estrus = day 0) were incubated for 0-120 min at 37 degrees C in F-10 medium + 0.1% BSA containing various concentrations of H2O2 (0-1000 microM). Cells were washed with catalase (2800 U/ml), and then with fresh medium. Cell viability based on trypan blue exclusion was unaltered by H2O2 exposure through 60 min. H2O2-exposed cells were incubated with fluorescent-tagged-LDL (Dil-LDL; 1 microgram/ml) for 10 min at 37 degrees C. Fluorescence of small (SLC) and large (LLC) luteal cells was analyzed by flow cytometry (n = 6 experiments). H2O2 (> or = 10 microM) caused a progressive reduction (P < 0.01) in mean fluorescence intensity (MFI) of SLC and LLC indicative of up to a 30-35% decline in LDL uptake. Progesterone (P) production: dispersed luteal cells (4 x 10(4)/0.2 ml) were pre-cultured in DMEM/F-12 medium overnight (approximately 18 h) in 96-well culture plates. Wells were rinsed and fresh media (0.2 ml) containing H2O2 (0-500 microM) was added. After 30 min, the following treatments were added: human(h)LDL (0 or 50 micrograms/ml), human chorionic gonadotropin (hCG; 0 or 100 ng/ml), hCG + LDL, or 22R-hydroxycholesterol (22[OH]-C; 0 or 25 micrograms/ml). Cells were incubated for an additional 4 h, and P concentrations in final media samples were measured by RIA.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Cell Endocrinol 1995 Jun
PMID:Hydrogen peroxide suppresses low-density lipoprotein (LDL) uptake and LDL-supported steroidogenesis by porcine luteal cells. 755 84

Endometrial fibroblasts derived from uterine endometrium as controls and endometrial cancer cells (Ishikawa and HHUA cells) were used to analyze the manner of induction of c-Ha-ras transcripts in endometrial cancers, some of which are estrogen-dependent in growth. Estrogen increased c-Ha-ras expression and tyrosine kinase (TK) activity in fibroblast and Ishikawa cells, but not in HHUA cells. Progesterone diminished c-Ha-ras expression and tyrosine kinase (TK) activity induced by estradiol in the fibroblasts, but not in Ishikawa cells, which persistently overexpressed c-Ha-ras. In these cells, epidermal growth factor (EGF) increased c-Ha-ras expression as did estradiol. Pretreatment with tyrphostin, an inhibitor of TK, abolished estrogen-inducible overexpression of c-Ha-ras. The combination of both estradiol and EGF at maximum effective concentration exerted no additive or synergistic effect on induction of c-Ha-ras expression. In conclusion, persistent activation of TK might lead to overexpression of c-Ha-ras in some endometrial cancer cells under estrogen predominant milieu, which might be associated with the transformation or growth potential.
J Steroid Biochem Mol Biol 1995 Oct
PMID:Estrogen induces c-Ha-ras expression via activation of tyrosine kinase in uterine endometrial fibroblasts and cancer cells. 757 18

The effects of PCBs (mixture of 2, 3, 4, 5-tetra; 2, 2', 4, 5, 5'-penta; 2, 2', 3, 3', 6, 6'-hexa and 2, 2', 3, 3', 4, 4', 5, 5'-octa congeners) on androgen production were investigated by suspension of Leydig cells from adult rat testis. hCG-stimulated androgen production was significantly inhibited by PCBs while progesterone level was not affected. Progesterone supported testosterone production was also decreased by PCBs, while conversion of androstenedione to testosterone was unchanged. These results suggest that the activity of microsomal enzyme C21 side-chain cleavage P450 was decreased by PCB treatment of Leydig cells in vitro.
J Steroid Biochem Mol Biol 1995 Jun
PMID:Effect of PCBs on androgen production by suspension of adult rat Leydig cells in vitro. 777 64

Progesterone hydroxylase cytochrome P-450 was purified to homogeneity from Phycomyces blakesleeanus microsomes by a four step procedure. An M(r) value of 60,000 was determined for this protein by SDS-PAGE. The DEAE-cellulose and Blue-1 MIMETIC affinity fractions gave major peaks at 452 nm in a dithionite-reduced, carbon monoxide, difference spectrum. NaIO4-dependent progesterone hydroxylation was obtained by the pure enzyme without NADPH and NADPH-cytochrome P-450 reductase. NADPH-dependent hydroxylation required the addition of other Phycomyces microsomal proteins present in the Blue-1 fraction.
J Steroid Biochem Mol Biol 1995 Feb
PMID:Microbial transformation of steroids--IX. Purification of progesterone hydroxylase cytochrome P-450 from Phycomyces blakesleeanus. 787 54

We have described previously the presence of binding sites in particulate fractions of the porcine corpus luteum (CL) which were specific for progesterone. We now demonstrate the presence of similar progesterone-specific binding sites in particulate fractions of the ovine CL. Preincubation of ovine luteal membranes with radiolabelled steroids demonstrated binding of progesterone and pregnenolone to a low-density particulate fraction (1.07-1.09 g/cm3). Preincubation with digitonin perturbed the buoyant density of this fraction (to 1.10-1.14 g/cm3) without causing release of steroid. Androgens and oestrogens did not bind appreciably to control luteal membranes, but were bound when preincubated with digitonin. In contrast, steroid conjugates (oestrone sulfate, pregnanediol glucuronide), cortisol, fatty acids (arachidonic acid, prostaglandin F2 alpha) and cholesterol ester failed to bind to ovine luteal membranes, with or without digitonin pretreatment. The effects of digitonin on steroid binding led us to examine its effects on steroid binding to ovine luteal membrane fractions in vitro. Specific progesterone binding was absent in the absence of digitonin, even at very high membrane concentrations. However, binding of 3H-labelled progesterone was stimulated 5-15-fold in a dose-dependent fashion by increasing digitonin concentrations, reaching a plateau at about 100 microM. In the presence of digitonin, [3H]progesterone binding increased linearly with luteal membrane concentration. Other detergents, saponins and cardiotonic steroids tested did not stimulate progesterone binding to ovine luteal membranes. [3H]Progesterone binding was dependent on the pH, duration and temperature of incubation. Unlabelled progesterone decreased binding of [3H]progesterone (half-maximal displacement of specific binding (IC50) at about 60 nM) whereas androgens were less potent (IC50, 500-3300 nM), whilst a wide range of other steroids and inhibitors of steroidogenic enzymes were ineffective, except at very high concentrations. Similarly, a number of progesterone receptor agonist and antagonist analogues failed to compete for progesterone binding to luteal membranes, suggesting that these binding sites were unrelated to progesterone receptors. Modifications to the 3, 4, 5 and 11 positions of progesterone, removal of the steroid side-chain or aromatization of the A-ring decreased binding potency dramatically, whereas changes to the 17 or 20 positions had relatively minor effects. Our results indicate the presence of a low density particulate fraction in ovine corpora lutea which contains specific binding sites for endogenous and exogenous progesterone.
Mol Cell Endocrinol 1994 Jul
PMID:Particulate binding sites for steroid hormones in subcellular fractions of the ovine corpus luteum: properties and hormone specificity. 795 96

Porcine granulosa cells have been shown previously to both secrete and respond to insulin-like growth factor-I (IGF-I), suggesting an autocrine function of this peptide in the follicle. The present work was undertaken to determine possible effects of IGF-I on in vitro maturation, in vitro fertilization, and early embryonic development in culture. Granulosa and cumulus cell proliferation and differentiation based on 3H-thymidine uptake and progesterone production, respectively, were also assessed. The results showed that the cleavage rate of oocytes was markedly stimulated in a dose-dependent manner by the addition of IGF-I to the oocyte maturation medium (P < 0.05). Embryo development beyond the 8-cell stage was improved by IGF-I, reaching a maximum of 22% at 200 ng/ml IGF-I. Treatment with IGF-I after fertilization increased the percentage of total oocyte cleavage (P < 0.05) to approximately 52%, 43%, and 57% at, respectively, 25, 50, and 100 ng/ml IGF-I. 3H-thymidine incorporation by granulosa cells was significantly increased in cultures treated with FSH (3-fold) or IGF-I (6-fold) compared to the control. For the cumulus cells, FSH caused a similar increase (3-fold) in 3H-thymidine incorporation while IGF-I stimulated a 15-fold increase. Progesterone production by the granulosa cells was increased to the same extent by treatment with FSH or IGF-I (4.7 and 5.1-fold, respectively). However, for the cumulus cells, while FSH caused a marked 16-fold increase in progesterone production, IGF-I caused only a marginal increase of 2.5-fold.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Reprod Dev 1994 Aug
PMID:Effect of IGF-I on pig oocyte maturation, fertilization, and early embryonic development in vitro, and on granulosa and cumulus cell biosynthetic activity. 798 Sep 45

Progesterone metabolism by guinea pig amnion, chorion, myometrium, and endometrium was studied at the following gestational stages. Day 45 represents mid-gestation, about 5 days before strong chorion interaction between the entire surface of the chorion and the uterus; days 57-58, 1-2 days after chorion attachment, and 2-3 days before the onset of pubic symphysis relaxation; days +1-+6, 1-6 days after the onset of pubic symphysis relaxation, i.e. within 1 week of parturition. The high metabolic activity of chorion exceeded that by amnion at all stages. Metabolism by endometrium and myometrium was always low. Conversion of progesterone by amnion significantly decreased (P < 0.05) between days 57-58 and days +1-+6. Progesterone metabolites produced by chorion and amnion were identified by TLC, HPLC, and capillary GC/MS. Both tissues converted progesterone to three major products during 60-min incubations. These were 5 alpha-pregnane-3,20-dione, 3 alpha-hydroxy-5 alpha-pregnan-20-one, and 3 beta-hydroxy-5 alpha-pregnan-20-one. The metabolite pattern differed between the two tissues. Three-minute incubations with chorion resulted in a significantly higher proportion of 3 alpha-hydroxy-4-pregnen-20-one (P < 0.01) and 5 alpha-pregnane-3,20-dione (P < 0.025) than at 60 min. The production of 3 beta-hydroxy-5 alpha-pregnen-20-one by chorion decreased (P < 0.05) between days 50-51 and 57-58. The ratio of 3 alpha-hydroxy-5 alpha-pregnan-20-one to 3 beta-hydroxy-5 alpha-pregnan-20-one increased (P < 0.05) between days 45 post-relaxation. The marked conversion of progesterone by chorion, or the formation of one or more of its metabolites, may serve to influence uterine function prior to delivery.
J Steroid Biochem Mol Biol 1994 Nov
PMID:Progesterone metabolism by guinea pig intrauterine tissues. 798 Nov 29


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