Document Detail

The anovulatory hamster: a comparison of the effects of short photoperiod and daily melatonin injections on the induction and termination of ovarian acyclicity.
MedLine Citation:
PMID:  6792319     Owner:  NLM     Status:  MEDLINE    
Cyclic female hamsters were rendered anovulatory by daily subcutaneous melatonin injections (25 microgram/0.1 ml oil) in 29 days or by transfer to a short light cycle, LD 6:18 (lights 1000-1600 hrs) in 33 days. Estrous cyclicity was reinitiated in these animals in 44 or 45 days following cessation of melatonin injections or transfer to long light cycles (LD 14:10, lights 0600-2000 hrs), respectively. Exposure of both groups to LD 6:18 after reinitiation of estrous cyclicity caused a second cessation of ovulation in 75 (melatonin group) or 61 (short light cycle group) days. Thus, although both treatments disrupted estrous cyclicity for nearly 6 weeks, this was not sufficient to induce photorefractoriness (failure to respond to short light cycles with continued estrous cyclicity). Rather, every animal responded to LD 6:18 and ceased ovulating. Melatonin-induced anovulatory hamsters showed daily gonadotropin release patterns identical to those reported in hamsters in other anovulatory states (lactating, prepubertal, and photoinduced anovulatory hamsters); that is, peak LH and FSH release at 1700 hrs daily.
M H Stetson; B Hamilton
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of experimental zoology     Volume:  215     ISSN:  0022-104X     ISO Abbreviation:  J. Exp. Zool.     Publication Date:  1981 Feb 
Date Detail:
Created Date:  1981-11-22     Completed Date:  1981-11-22     Revised Date:  2005-11-17    
Medline Journal Info:
Nlm Unique ID:  0375365     Medline TA:  J Exp Zool     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  173-8     Citation Subset:  IM    
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MeSH Terms
Follicle Stimulating Hormone / blood
Luteinizing Hormone / blood
Melatonin / pharmacology
Ovary / physiology*
Ovulation* / drug effects,  radiation effects*
Time Factors
Reg. No./Substance:
73-31-4/Melatonin; 9002-67-9/Luteinizing Hormone; 9002-68-0/Follicle Stimulating Hormone

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

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