Publication Date:
1979-04-20
Description:
The normal ovarian cycle of female rats is typically replaced by persistent estrus when these animals are housed under constant light. Evidence presented here shows that the maintenance of periodicity in the environment can at least delay (if not prevent) the photic induction of persistent vaginal estrus. Female rats in constant light were exposed to vaginal smearing at random times or at the same time every day. In another experiment, female rats were exposed to either constant bright light, constant dim light, or a 24-hour photic cycle of bright and dim light. The onset of persistent vaginal estrus was delayed in rats exposed to 24-hour time cues even though the light intensities were the same as or greater than those for the aperiodic control groups. The results suggest that the absence of 24-hour time cues in constant light contributes to the induction of persistent estrus.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Weber, A L -- Adler, N T -- New York, N.Y. -- Science. 1979 Apr 20;204(4390):323-5.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/571146" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Biological Clocks
;
Dose-Response Relationship, Radiation
;
Estrus/*radiation effects
;
Female
;
*Light
;
Periodicity/radiation effects
;
Pregnancy
;
Rats
;
Time Factors
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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