Document Detail


Site-specific decrease of progesterone receptor mRNA expression in the hypothalamus of middle-aged persistently estrus rats.
MedLine Citation:
PMID:  12419537     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Middle-aged females gradually become acyclic and spontaneously develop a persistently estrus (PE) state. PE rats, acyclic for 30 days (early PE), are unresponsive to the positive feedback action of estrogen, but respond to a progesterone challenge with a luteinizing hormone (LH) surge and ovulation; unlike long-term PE rats, acyclic for 90 days, neither estrogen nor estrogen plus progesterone will elicit an LH surge [10th International Congress of Endocrinology, San Francisco, P3 (1996) 1061]. We hypothesize that the PE state may develop due to a diminished level of estrogen-induced progesterone receptor (PR) expression in the hypothalamus that prevents progesterone from stimulating LH regulating circuits. To test this hypothesis, PR mRNA levels were measured in hypothalamic regions of young, proestrus (2-3 months of age), early PE (10-12 months) and long-term PE (13-15 months) rats. The anteroventral periventricular nucleus (AVPV), an important regulatory site of the LH surge, had decreased PR mRNA levels in early and long-term PE rats compared with proestrus rats. However, PR mRNA levels were reduced only in long-term PE rats in the ventromedial nucleus (VMH) and arcuate nucleus (ARH). In the medial preoptic nucleus (MPN), levels of PR mRNA did not change. A previous report showed that exogenous progesterone stimulates an LH surge in young and early PE animals, indicating that the expression of PR mRNA demonstrated in this study is sufficient to mediate progesterone facilitation of the LH surge in early PE rats. In acyclic, long-term PE rats, diminished estrogen-induced expression of progesterone receptors is correlated with a previously shown inability to respond to exogenous progesterone.
Authors:
Richard H Mills; Horacio E Romeo; John K H Lu; Paul E Micevych
Related Documents :
7200117 - Androgen and oestrogen concentrations in the ovary of the cyclic rat.
300097 - Environmental influence on ovulation and embryonic development in rana pipiens.
8584757 - Central administration of antisense oligodeoxynucleotides to neuropeptide y (npy) mrna ...
6306747 - Effect of tetrahydrocannabinols on pubertal body weight spurt and sex hormones in devel...
2226717 - Effects of selective dopamine d1 and d2 antagonists on male rat sexual behavior.
7423537 - Acetylcholinesterase activity in rat brain: effect of acute cyanide intoxication.
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Brain research     Volume:  955     ISSN:  0006-8993     ISO Abbreviation:  Brain Res.     Publication Date:  2002 Nov 
Date Detail:
Created Date:  2002-11-06     Completed Date:  2003-01-31     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0045503     Medline TA:  Brain Res     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  200-6     Citation Subset:  IM    
Affiliation:
Department of Neurobiology, UCLA School of Medicine, Los Angeles, CA 90095-1763, USA. rhmills@ucla.edu
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Aging / genetics,  metabolism*
Animals
Estrus / genetics,  metabolism*
Female
Gene Expression Regulation / physiology*
Hypothalamus / metabolism*
RNA, Messenger / biosynthesis*
Rats
Rats, Long-Evans
Receptors, Progesterone / biosynthesis*,  genetics
Grant Support
ID/Acronym/Agency:
HD07228/HD/NICHD NIH HHS; NS39495/NS/NINDS NIH HHS
Chemical
Reg. No./Substance:
0/RNA, Messenger; 0/Receptors, Progesterone

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Apolipoprotein E alters the processing of the beta-amyloid precursor protein in APP(V717F) transgeni...
Next Document:  Effect of repeated administration of prolactin releasing peptide on feeding behavior in rats.