help button home button Endocrine Society Endocrinology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Article
Right arrow Full Text (PDF)
Right arrow Purchase Article
Right arrow View Shopping Cart
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Copyright Permission
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Karkanias, G. B.
Right arrow Articles by Etgen, A. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Karkanias, G. B.
Right arrow Articles by Etgen, A. M.

Endocrinology, Vol 136, 1993-1999, Copyright © 1995 by Endocrine Society

ARTICLES

Progesterone attenuation of alpha 1-adrenergic receptor stimulation of phosphoinositol hydrolysis in hypothalamus of estrogen-primed female rats

GB Karkanias, N Petitti and AM Etgen
Departments of Neuroscience and Psychiatry, Albert Einstein College of Medicine, Bronx, New York 10461, USA.

These experiments examined whether the previously observed abolition by progesterone (P) of alpha 1-adrenergic potentiation of adenylyl cyclase activity in brain slices of estrogen-primed female rats is attributable to a reduced capacity of alpha 1-adrenoceptors to stimulate phosphoinositol hydrolysis. In preoptic area and hypothalamic slices from ovariectomized (OVX) female rats, both norepinephrine (NE) and the alpha 1-adrenergic agonist phenylephrine (PHE) were robust stimulators of inositol phosphate (IP) formation. The NE response was completely blocked by the alpha 1-adrenergic antagonist prazosin. PHE-induced IP formation in tissue from OVX females exposed for 48 h to estrogen alone was comparable to that in OVX controls. In hypothalamic tissue from OVX rats given estrogen plus P, NE and PHE activation of phosphoinositol hydrolysis was attenuated. Both chlorethylclonidine, an irreversible antagonist of alpha 1b-adrenoceptors, and 5-methylurapidil, an alpha 1a- selective antagonist, reduced NE-induced IP formation regardless of the hormonal condition of the animals. Analysis of PHE competition for [3H]prazosin binding indicated that agonist binding was of high affinity (Ki, 16-30 microM) and was unaffected by hormonal status. Therefore, P abolition of alpha 1-adrenergic augmentation of adenylyl cyclase is correlated with reduced phosphoinositol hydrolysis, but not with changes in alpha 1-adrenoceptor agonist binding affinity. Moreover, both alpha 1a- and alpha 1b-adrenoceptors appear to work together to stimulate this second messenger system in the female rat hypothalamus.


This article has been cited by other articles:


Home page
 J. Pharmacol. Exp. Ther.Home page
M. L. Laorden, G. Fuertes, A. González-Cuello, and M. V. Milanés
Changes in Catecholaminergic Pathways Innervating Paraventricular Nucleus and Pituitary-Adrenal Axis Response during Morphine Dependence: Implication of alpha 1- and alpha 2-Adrenoceptors
J. Pharmacol. Exp. Ther., May 1, 2000; 293(2): 578 - 584.
[Abstract] [Full Text]

Home page
 J. Neurosci.Home page
H.-P. Chu and A. M. Etgen
Ovarian Hormone Dependence of alpha 1-Adrenoceptor Activation of the Nitric Oxide-cGMP Pathway: Relevance for Hormonal Facilitation of Lordosis Behavior
J. Neurosci., August 15, 1999; 19(16): 7191 - 7197.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Endocrinology Endocrine Reviews J. Clin. End. & Metab.
Molecular Endocrinology Recent Prog. Horm. Res. All Endocrine Journals
Copyright © 1995 by The Endocrine Society