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Effect of gonadal steroids upon hypothalamic oxytocin expression.

Amico, JA and Crowley, RS and Insel, TR and Thomas, A and O'Keefe, JA (1995) Effect of gonadal steroids upon hypothalamic oxytocin expression. Adv Exp Med Biol, 395. 23 - 35. ISSN 0065-2598

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Oxytocin (OT) has been implicated in reproductive events. Gonadal steroids, which are also essential for reproduction, may in these instances influence the expression of the OT gene. The relationship between gonadal steroids and OT expression is incompletely understood. First, although estrogen (E) induces OT expression in heterologous in vitro systems and the OT gene contains an estrogen response element, evidence for a stimulatory effect of E upon OT mRNA in vivo as in the rat hypothalamus has been lacking. Second, an enhanced and coordinated expression of OT and vasopressin (AVP), mRNA during late pregnancy and lactation is not expected. This is especially true in lactation, during which suckling selectively activates OT, not AVP, neurons. We now report that E does increase OT mRNA levels in the rat hypothalamus. Ovariectomized rats were implanted initially with E, followed by progesterone (P) 48 hrs later; both were sustained for 12 days and the P implants were removed 48 hrs prior to sacrifice. By in situ and Northern blot hybridizations, OT, but not AVP, mRNA was increased in the hypothalamus of animals receiving this regimen compared to sham treated cohorts. A similar phenomenon associated with exposure to E and P followed by P withdrawal occurs in physiologic states such as day 21 of pregnancy, day 10-12 of lactation, and with interruption of the suckling stimulus for 48 hrs. If E was not administered or if P was not withdrawn prior to sacrifice, no increase was found in OT mRNA. Our data highlight the pivotal role of P withdrawal in the induction of the hypothalamic OT gene in the E-primed rat.


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Item Type: Article
Status: Published
CreatorsEmailPitt UsernameORCID
Amico, JA
Crowley, RS
Insel, TR
Thomas, A
O'Keefe, JA
Date: 1995
Date Type: Publication
Journal or Publication Title: Adv Exp Med Biol
Volume: 395
Page Range: 23 - 35
Schools and Programs: School of Medicine > Biomedical Informatics
Refereed: Yes
Uncontrolled Keywords: Animals, Estrogens, Female, Gene Expression, Hypothalamus, Lactation, Ovariectomy, Ovary, Oxytocin, Pregnancy, Progesterone, RNA, Messenger, Rats, Rats, Sprague-Dawley, Receptors, Estrogen, Steroids
ISSN: 0065-2598
Funders: NIDDK NIH HHS (5 T32 DK07052-21)
MeSH Headings: Animals; Estrogens--administration & dosage; Estrogens--pharmacology; Female; Gene Expression--drug effects; Hypothalamus--drug effects; Hypothalamus--metabolism; Lactation; Ovariectomy; Ovary--physiology; Oxytocin--genetics; Pregnancy; Progesterone--administration & dosage; Progesterone--pharmacology; RNA, Messenger--genetics; RNA, Messenger--metabolism; Rats; Rats, Sprague-Dawley; Receptors, Estrogen--biosynthesis; Steroids--pharmacology
PubMed ID: 8713949
Date Deposited: 29 Aug 2012 20:17
Last Modified: 14 Oct 2017 05:57


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