Document Detail

Estradiol deficiency during development modulates the expression of circadian and daily rhythms in male and female aromatase knockout mice.
MedLine Citation:
PMID:  21816154     Owner:  NLM     Status:  Publisher    
Gonadal steroids modify the phase, amplitude and period of circadian rhythms. To further resolve the role of estradiol, we examined daily patterns of activity, circadian free running period and behavioral responses to light pulses using aromatase deficient (ArKO) mice. These animals lack the enzyme necessary to produce estradiol. We hypothesized that circulating estrogens during development and adulthood modulate the amount of activity, the temporal relationship of activity patterns relative to a light:dark cycle, and the free running period. Intact and gonadectomized male and female ArKO and wildtype (WT) littermates were used. WT males, but not ArKO males, retained the ability to respond to steroid hormones; the time of activity onset, free running period in constant darkness, and total daily activity were significantly different in gonadectomized compared to intact males. In contrast, gonadectomy did not alter the expression of these variables in ArKO males. ArKO females had a longer free running period in constant darkness compared to WT females regardless of gonadal state. Ovariectomized ArKO females had a significantly delayed activity onset when compared to intact ArKO females and ovariectomized WT females, despite all 3 groups being estrogen deficient. Phase shifts in response to light pulses given at different times of the day revealed an interaction between genotype, sex, and circulating steroids. These results from ArKO animals strongly suggest an organizational effect of estradiol during a critical period of development on the expression of biological rhythms.
Rebecca Brockman; David Bunick; Megan M Mahoney
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-7-27
Journal Detail:
Title:  Hormones and behavior     Volume:  -     ISSN:  1095-6867     ISO Abbreviation:  -     Publication Date:  2011 Jul 
Date Detail:
Created Date:  2011-8-5     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0217764     Medline TA:  Horm Behav     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2011. Published by Elsevier Inc.
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