Document Detail

Timing of birth in Syrian hamsters.
MedLine Citation:
PMID:  1637949     Owner:  NLM     Status:  MEDLINE    
The effects of mating time and of LD cycles on the timing of birth and length of gestation were examined in Syrian hamsters (Mesocricetus auratus). Hamsters maintained on 14L:10D cycles were mated for 2 h either in the evening or in the morning, and groups of hamsters mated in the morning were subjected to either a 6-h advance shift or a 6-h delay shift of the LD cycle on Days 5-14 of gestation. For the last 2 days of gestation the hamsters were kept in constant dim light and observed every hour to determine the time of birth. Hamsters mated in the evening gave birth an average of 4.8 h before those mated in the morning, and the hamsters subjected to an advance shift gave birth an average of 8.1 h before those subjected to delay shift. The results show that 80-100% of births occur during the subjective day on Day 16 of gestation and that the minimum duration of gestation is 15 days and 2 h. The regulation of birth appears to involve two processes, an interval timer related to the time of conception and a circadian rhythm that is governed by the LD cycle.
N Viswanathan; F C Davis
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Biology of reproduction     Volume:  47     ISSN:  0006-3363     ISO Abbreviation:  Biol. Reprod.     Publication Date:  1992 Jul 
Date Detail:
Created Date:  1992-08-28     Completed Date:  1992-08-28     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0207224     Medline TA:  Biol Reprod     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  6-10     Citation Subset:  IM    
Department of Biology, Northeastern University, Boston, Massachusetts 02115.
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MeSH Terms
Circadian Rhythm / physiology*
Labor, Obstetric / physiology*
Sexual Behavior, Animal / physiology
Time Factors
Grant Support

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

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