Document Detail

Changes in Vitellogenin expression during captivity-induced stress in a tropical anole.
MedLine Citation:
PMID:  8812375     Owner:  NLM     Status:  MEDLINE    
Tropical anoline lizards have been shown to undergo massive reproductive retrogression when held in captivity. The present study focused on the effects generated by captivity-induced stress on the hepatic expression of vitellogenin (Vtg), the precursor of the major egg yolk proteins, in Anolis pulchellus. Several hepatic dysfunctions accompanying the regression of the reproductive organs were detected when mature highly vitellogenic females were kept in captivity for long periods. These included decreased synthesis of Vtg to undetectable levels after 4 days of captivity concomitant with a large reduction in the levels of its cognate mRNA. In addition, a drastic reduction in Vtg plasma levels preceding the conspicuous cessation of follicular growth was observed. Results suggest the activation of a specific mechanism for rapid clearance of vitellogenic and other female-specific proteins from plasma. The effects of captivity, both in the liver and in the reproductive tract, were alleviated or even reversed by treatment with 17 Beta-estradiol. Hepatic protein synthesis increased threefold when animals were maintained under estrogen therapy during the captivity period. Also, the levels of Vtg mRNA and Vtg protein synthesis and plasma levels were similar or even higher to the observed in control vitellogenic females. Animals treated with 17 beta-estradiol after long-term captivity recovered the normal vitellogenic levels after 72 to 96 hr. Therefore, our results im this tropical anole strongly suggest that the stress effects upon reproductive behavior previously reported in anoline lizards results from suppression of the estrogen stimulus for the hepatic vitellogenic response.
M H Morales; E J Sánchez
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  General and comparative endocrinology     Volume:  103     ISSN:  0016-6480     ISO Abbreviation:  Gen. Comp. Endocrinol.     Publication Date:  1996 Aug 
Date Detail:
Created Date:  1996-12-19     Completed Date:  1996-12-19     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0370735     Medline TA:  Gen Comp Endocrinol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  209-19     Citation Subset:  IM    
Department of Biology, University of Puerto Rico, San Juan, Puerto Rico.
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MeSH Terms
Blood Proteins / biosynthesis
Estradiol / pharmacology
Gene Expression*
Liver / drug effects,  metabolism
Lizards / metabolism*
RNA, Messenger / metabolism
Stress, Physiological / metabolism*
Vitellogenins / biosynthesis,  blood,  genetics*
Reg. No./Substance:
0/Blood Proteins; 0/RNA, Messenger; 0/Vitellogenins; 50-28-2/Estradiol

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

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