Please use this identifier to cite or link to this item: http://ahro.austin.org.au/austinjspui/handle/1/9248
Title: Tissue-specific regulation of gastrin-releasing peptide synthesis, storage and secretion by oestrogen and progesterone.
Authors: Whitley, J C;Giraud, A S;Mahoney, A O;Clarke, I J;Shulkes, Arthur
Affiliation: jacecw@austin.unimelb.edu.au
Department of Surgery, University of Melbourne, Austin and Repatriation Medical Centre, Austin Campus, Melbourne, Victoria 3084 Australia
Issue Date: 1-Sep-2000
Citation: The Journal of Endocrinology; 166(3): 649-58
Abstract: In the ovine endometrium, dramatic increases in gastrin-releasing peptide (GRP) mRNA and immunoreactivity are observed during the luteal regression phase of the oestrous cycle (24-fold) and during pregnancy (at least 150-fold). This study sought to determine whether oestrogen and/or progesterone were responsible for the temporal regulation of GRP observed in the uterus. Ovariectomized sheep were divided into four groups (n=4), as follows: 1, untreated; 2, given subcutaneous and intravaginal progesterone implants; 3, given subcutaneous oestrogen implants; and 4, treated with both oestrogen and progesterone. After 10 days, the animals were sacrificed and plasma, pituitary and endometrium were obtained. A fifth group of sheep with intact ovaries was included. Analysis of endometrial GRP-immunoreactivity (GRP-ir) revealed a twofold drop for groups treated with oestrogen, progesterone or both hormones. A dramatic reduction in endometrial GRP mRNA was o! bserved in the group treated with both hormones. GRP-ir was measured in whole pituitaries and found to vary greatly (1.7-53.7 pmol/g tissue) within all groups of ovariectomized animals. There were no significant differences between any of the five groups. A significant reduction in circulating GRP-ir was observed after 10 days of treatment with either oestrogen or progesterone. These studies demonstrate that, in sheep, the synthesis, storage and secretion of GRP are differentially affected by oestrogen and progesterone. Regulation appears to be tissue specific since GRP content in the pituitary is unchanged by oestrogen or progesterone whereas GRP expression in the endometrium is inhibited. Changes in GRP mRNA expression did not correlate with changes in endometrial expression of mRNA for oestrogen receptor alpha, oestrogen receptor beta and the progesterone receptor. This study is the first reported demonstration that expression of the GRP gene can be influenced by the presence of ovarian steroids, with the conclusion that oestrogen and/or progesterone act as negative regulators of endometrial GRP expression.
Internal ID Number: 10974658
URI: http://ahro.austin.org.au/austinjspui/handle/1/9248
URL: http://www.ncbi.nlm.nih.gov/pubmed/10974658
Type: Journal Article
Subjects: Actins.genetics
Animals
Blotting, Northern
Drug Implants
Endometrium.drug effects.metabolism
Estrogens.pharmacology
Female
Gastrin-Releasing Peptide.biosynthesis.metabolism.secretion
Ovariectomy
Pituitary Gland.metabolism
Progesterone.pharmacology
RNA, Messenger.analysis
Receptors, Estrogen.genetics
Receptors, Progesterone.genetics
Reverse Transcriptase Polymerase Chain Reaction
Sheep
Appears in Collections:Journal articles

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