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

Pituitary cells cultured with estradiol respond by a specific increase in prolactin synthesis. Extensive inhibition of DNA synthesis (61-78%) with hydroxyurea or cytosine arabinoside resulted in only 28-33% decrease in estrogen-induced prolactin synthesis. To assess the role of prolactin cell proliferation in the estrogen-induced response, mammotrophs were identified by immunocytochemistry. Cultures treated with estradiol for 1, 2 or 5 days contained 101 +/- 1, 113 +/- 2 and 132 +/- 1% of the number of mammotrophs in controls. Estradiol treatment for corresponding periods resulted in prolactin synthesis representing 94 +/- 5, 144 +/- 11 and 270 +/- 22% of controls and prolactin mRNA levels representing 115 +/- 7, 160 +/- 7 and 322 +/- 22% of controls. Thus estrogen caused a considerable increase in prolactin synthesis which paralleled the increase in prolactin mRNA levels and a much smaller relative increase in the number of mammotrophs. We conclude that regulation of prolactin synthesis by estrogen is mediated predominantly but not exclusively through stimulation of gene expression in existing pituitary cells.
Mol Cell Endocrinol 1982 Mar
PMID:Prolactin synthesis in primary cultures of pituitary cells: regulation by estradiol. 706 28

The in vitro effects of progesterone, testosterone and estradiol-17 beta on steroid accumulation by isolated rabbit follicles were examined. Progesterone had no effect on LH-stimulated androgen accumulation but inhibited LH-stimulated estrogen accumulation at 10(-7) M and 10(-6) M. Testosterone at 10(-5) M but not at 10(-6) M or 10(-7) M, inhibited LH-stimulated progesterone accumulation. LH-stimulated estrogen accumulation was inhibited at all dose levels of testosterone. Estradiol (10(-5) M) inhibited LH-stimulated androgen accumulation and had no effects on progesterone accumulation. It is concluded that the steroidal milieu of follicles can influence their response to LH.
Mol Cell Endocrinol 1982 Apr
PMID:In vitro effects of sex steroids on LH-stimulated steroid accumulation by isolated rabbit ovarian follicles. 708 61

The hormonal regulation of uterine and oviductal cytoplasmic estrogen and progesterone receptors was studied in immature beagles that were untreated, treated with estradiol-17 beta, or treated sequentially with estradiol and progesterone. Estradiol treatment increased the concentration of estrogen receptors in both tissues. Progesterone receptors were not detectable in the reproductive tract of untreated animals, but increased dramatically under the influence of estradiol. Estrogen withdrawal following estrogen stimulation concomitant estrogen plus progesterone administration, and estrogen withdrawal plus progesterone administration all caused significant reductions in both estrogen and progesterone receptors in uterine oviductal cytosols when compared to estrogen treatment alone. Estrogen withdrawal resembled estrogen plus progesterone administration in reducing both estrogen and progesterone receptor levels, although estrogen withdrawal plus progesterone administration resulted in a further reduction in both receptor concentrations. The same positive and negative relationships between estrogen and progesterone receptor content were observed in uterine cytosols from cycling and ovariectomized adults. These data suggest that estrogen and progesterone regulate their respective receptors and that tissue sensitivity to both steroids may be controlled by mechanisms involving fluctuations in receptor concentration in the reproductive tract of the beagle.
Mol Cell Endocrinol 1981 Feb
PMID:Hormonal regulation of cytoplasmic estrogen and progesterone receptors in the beagle uterus and oviduct. 721 1

We studied the influence of sex hormones using the hormone-sensitive levator ani muscle as a model tissue and glucose-6-phosphate dehydrogenase as an indicator of hormone action. Injection of testosterone or estradiol cause a 50% increase in the specific activity of glucose-6-phosphate dehydrogenase. The effect was dose-dependent, and was maximal at a dose of 2.5mg/100g body weight. Estradiol increased glucose-6-phosphate dehydrogenase as early as 8 h after injection, while testosterone required 12 h. Injection of estradiol on 2 successive days increased enzyme activity by 80%. The effect of estradiol was abolished by actinomycin D, suggesting enzyme induction. The results indicate a direct effect of estrogen on striated muscle.
Mol Cell Endocrinol 1980 Feb
PMID:Effect of sex hormones on glucose-6-phosphate dehydrogenase in rat levator ani muscle. 736 48

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 transdermal delivery of steroids (TD) is gaining ground in hormone replacement therapy during menopause. This approach to treatment, however, has only recently been envisaged for contraception. Delivered in the appropriate solvent, both estrogens and progestins can penetrate the skin. Approximately 10% of any total dose applied topically is actually absorbed systemically. Currently available TD systems (TDS) are either of the reservoir type or of the matrix dispersion type in which the drug is dispersed into a polymer matrix. Estradiol is the most appropriate steroid for TD and can be combined with progestins to ensure a contraceptive effect. The use of potent progestins allows effective plasma levels to be reached with low doses through application over a small area of skin. TDS changed weekly and delivering both estradiol and levonorgestrel at daily dosages of 38.4 and 28.8 mcg per 10 sq. cm daily, respectively, was found to suppress ovulation. ST 1435, a synthetic progestin derived from 19-norprogesterone, has also been shown to penetrate the skin when suspended in acetylated lanolin or dissolved in a hydroalcoholic gel and to suppress ovulation at a dose of 2 mg per day in a small number of cycles. TD systems should be perfectly adhesive, well-tolerated locally, and nearly 100% effective.
J Steroid Biochem Mol Biol 1995 Jun
PMID:Transdermal application of steroid hormones for contraception. 762 63

The polymeric immunoglobulin receptor (poly Ig-R) mediates transcytosis of IgA and IgM antibodies produced by local plasma cells across epithelial cells of mucosal and glandular tissues. Gene expression of the poly-Ig R was analyzed in rabbit mammary gland during pregnancy and lactation. The poly Ig-R was expressed as early as day 8 (G8) of gestation and mRNA accumulation remained low until about G18. From G21, the mRNA abundance increased and reached steady state levels approximately 5-fold higher at day 15 of lactation (L15) when compared to basal levels at G8. The hormonal regulation of poly-Ig receptor gene expression was assessed in mammary organ cultures. Poly-Ig R mRNA accumulation in mammary explants cultured for 24 or 48 h in the presence of ovine prolactin (oPRL) was significantly increased to a maximal 4-fold level at 1 microgram ml-1 of oPRL. Estradiol (100 pg ml-1) or progesterone (1 microgram ml-1) did not further stimulate poly-Ig R expression. In contrast, their combination resulted in a significant 30-50% decrease of poly-Ig-R mRNA levels. The addition of 1 microgram ml-1 of cortisol to medium in the absence or presence of estradiol or progesterone decreased the amount of poly-Ig-R mRNA. The results suggest that until mid-pregnancy, poly-Ig-R expression is inhibited by elevated progesterone-estradiol concentrations and that the subsequent increase is due to the concomitant decrease of the two circulating steroids and the increase of serum prolactin levels.
Mol Cell Endocrinol 1995 Apr 28
PMID:Polymeric-Ig receptor gene expression in rabbit mammary gland during pregnancy and lactation: evolution and hormonal regulation. 767 55

The effect of structure of the estrogen ligand on the accumulation of tPA mRNA and the activity of extracellular fibrinolytic enzyme has been examined in cultures of MCF-7 cells. Estradiol(E2)-stimulated fibrinolytic activity was preceded by an increase in actinomycin D sensitive tPA mRNA synthesis which peaked at 18 h. Ten A- and D-ring structural analogs of E2 affected tPA mRNA accumulation and extracellular fibrinolytic activity. Only in the case of two A-ring isomers (2- and 4-hydroxyestratrien-17 beta-ol) was the decreased effect of the ligand's structural change on tPA mRNA accumulation and fibrinolysis not explained by a comparable decline in affinity of the ligand for estrogen receptor. Both of these analogs functioned as antiestrogens. The stimulatory capacity of androstanediols on the tPA gene required that the 3-hydroxyl group be positioned in the beta-configuration. Absence of the 17 beta-hydroxy group was beneficial to the maximum accumulation of tPA mRNA. As has been reported for other estrogen responsive genes (progesterone receptor, cathepsin D and pS2), regulation by estrogens is not related directly to the affinity of the ligand for ER, but this activity may be determined by the location of the electronegative isopotential above the A-ring of estrogenic ligands.
J Steroid Biochem Mol Biol 1995 May
PMID:Induction of tissue plasminogen activator mRNA and activity by structurally altered estrogens. 774 7

To study the mechanism of spermatogenesis during the premeiotic phase, a hybridoma producing monoclonal antibody (mAb) specific for early stages of spermatogenic cells was obtained. In immunohistochemical staining of adult testis, this mAb, designated as EE2, was able to react with type A to B spermatogonia and early meiotic cells, but not with Sertoli cells, Leydig cells, and other somatic tissues. Precursor cells of type A spermatogonia (gonocytes) were also positive for EE2 in perinatal mouse testis. The antigenic molecule recognized by mAb EE2 was a novel glycoprotein with molecular weight of 114 kDa, which had affinity with Con A and WGA lectins, and was susceptible to N-glycanase, suggesting the presence of asparagine-linked sugar chains. Furthermore, EE2 antigen was found to localize on the germ cell surface. The specific expression of this antigenic molecule suggests that it may play an important role in early spermatogenesis, of which only a little information is available at present.
Mol Reprod Dev 1995 Feb
PMID:Characterization of a novel spermatogenic cell antigen specific for early stages of germ cells in mouse testis. 776 15

The aim of this work is to evaluate the gonadotropin and growth factor effects in vitro on steroidal response in human granulosa luteal cells from polycystic ovaries compared with normal granulosa luteal cells in humans. The granulosa cells from polycystic (polycystic ovarian granulosa cells, POGC) and normo-ovulating women (normal cells, NC) were collected in the preovulatory phase after oocyte retrieval during the GIFT program. The cells were cultured serum-free for 24, 48 and 96 h. Estradiol and progesterone production was determined with or without HCG (1-200 ng/ml), FSH (10-300 ng/ml), insulin (1-50 micrograms/ml) and IGF I (1-50 ng/ml) addition. All treatments significantly induced a 2-3 fold estradiol increase at the 48-h and 96-h time points in POGC. The progesterone production was unaffected by HCG, FSH, insulin and IGF I addition, respectively, in POGC, whereas the NC were responsive at the 48-h and 96-h time points. FSH did not stimulate progesterone production in granulosa cells either from polycystic or normovulating subjects. Our findings indicate that POGC are hypersensitive to all substances in terms of estradiol production, whereas they show a reduced capacity of progesterone production with some treatments.
Mol Cell Endocrinol 1994 Dec
PMID:Effect of gonadotropins, insulin and IGF I on granulosa luteal cells from polycystic ovaries. 789 19


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