Document Detail

Pregnancy-related modifications of rat myometrial Gs proteins: ADP ribosylation, immunoreactivity and gene expression studies.
MedLine Citation:
PMID:  7999253     Owner:  NLM     Status:  MEDLINE    
Previous studies from our laboratory have suggested that post-receptor events at the level of beta-adrenergic receptor-adenylate cyclase interaction could be altered in myometrium by steroid hormones or pregnancy. In this study, we have addressed this question by performing a direct evaluation of rat myometrial Gs proteins at various stages of pregnancy or 24 h after administration of progesterone. In the 50,000 g myometrial plasma membrane fraction, in the presence of 32P-labelled NAD, cholera toxin ribosylated three predominant proteins with apparent molecular masses of 42, 47 and 55 kDa. Western blot analysis using the RM/1 antibody recognized the 42 and 47 kDa cholera toxin ADP-ribosylated bands but not the 55 kDa band. Thus, the 42 and 47 kDa immunoreactive bands were interpreted as being the small (Gs alpha-S) and large (Gs alpha-L) forms of Gs respectively. With a more purified myometrial plasma membrane fraction (105,000 g) an additional minor band of 44 kDa could be observed with both techniques. Treatment of late pregnant rats with 5 mg progesterone resulted in a significant increase in both Gs alpha subunits: +25% and +30% after ADP-ribosylation, +50% and +60% after Western blot analysis for Gs alpha-L and Gs alpha-S respectively. Pretreatment with the antiprogestin RU 486 completely suppressed the effect of progesterone, suggesting that the expression of Gs alpha subunits may be under the control of progesterone. However, changes in the myometrial content of Gs in progesterone-treated rats were not associated with concomitant variations in the steady-state levels of mRNA as demonstrated by Northern blot analysis. These data suggest a post-translational regulation of Gs expression by progesterone. Amounts of ADP-ribosylated Gs showed characteristic changes during the course of pregnancy with a fourfold or threefold increase (P < 0.05) on day 15 versus day 12 or delivery respectively. During pregnancy, or after progesterone administration, myometrial alterations of Gs strongly correlated (r = 0.913, P < 0.01) with the cholera toxin-stimulated adenylate cyclase activity. These findings provide evidence that changes in myometrial amounts of functional Gs i) are controlled by the hormonal status of pregnancy and progesterone and ii) play an important role in the transduction pattern of adenylate cyclase activity during the course of pregnancy.
J Elwardy-Mérézak; J P Maltier; J Cohen-Tannoudji; J L Lécrivain; V Vivat; C Legrand
Related Documents :
21308843 - Appearance of the fetal posterior fossa at 11+3 to 13+6 gestational weeks in transabdom...
21297473 - Nonabortal pregnancy complications of chorionic villous sampling.
6509133 - Changes in cysteine dioxygenase and cysteinesulfinate decarboxylase activities and taur...
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of molecular endocrinology     Volume:  13     ISSN:  0952-5041     ISO Abbreviation:  J. Mol. Endocrinol.     Publication Date:  1994 Aug 
Date Detail:
Created Date:  1995-01-20     Completed Date:  1995-01-20     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8902617     Medline TA:  J Mol Endocrinol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  23-37     Citation Subset:  IM    
Laboratoire de Physiologie de la Reproduction, CNRS URA 1449, Université Pierre et Marie Curie, Paris, France.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Adenosine Diphosphate Ribose / metabolism
Adenylate Cyclase / metabolism
Base Sequence
Cholera Toxin / metabolism
DNA Probes / genetics
Estradiol / pharmacology
GTP-Binding Proteins / genetics,  immunology,  metabolism*
Gene Expression / drug effects
Mifepristone / pharmacology
Molecular Sequence Data
Molecular Weight
Myometrium / drug effects,  metabolism*
Pregnancy, Animal / genetics,  metabolism*
Progesterone / pharmacology
RNA, Messenger / genetics,  metabolism
Rats, Sprague-Dawley
Reg. No./Substance:
0/DNA Probes; 0/RNA, Messenger; 20762-30-5/Adenosine Diphosphate Ribose; 50-28-2/Estradiol; 57-83-0/Progesterone; 84371-65-3/Mifepristone; 9012-63-9/Cholera Toxin; EC 3.6.1.-/GTP-Binding Proteins; EC Cyclase

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

Previous Document:  Overexpression of the extracellular domain of the thyrotrophin receptor in bacteria; production of t...
Next Document:  Negative control of the rat inhibin alpha subunit promoter in MA-10 Leydig tumour cells.