Document Detail

Seasonal fluctuation in diurnal rhythms of luteinizing hormone secretion in ewes during the mid-luteal phase of the oestrous cycle.
MedLine Citation:
PMID:  8464028     Owner:  NLM     Status:  MEDLINE    
Diurnal and seasonal fluctuations were detected in luteinizing hormone (LH) interpulse interval, but not amplitude, in ewes examined during the mid-luteal phase of an oestrous cycle at five stages of the breeding season. Daytime and night-time LH interpulse intervals were greater in the early and late than in the mid-breeding season (P < 0.05). During the early and late breeding season, LH interpulse interval was less during daylight than during darkness (P < 0.05). Toward the mid-breeding season, interpulse interval decreased during daytime earlier in the season than the night-time decrease. It was concluded that the diurnal fluctuations observed are a component of a circannual rhythm in LH secretion resulting from gradual seasonal transitions in photoperiodic drive to, or an endogenous rhythm in, the hypothalamic-pituitary axis in ewes.
W D Currie; R J Medhamurthy; S J Cook; N C Rawlings
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of reproduction and fertility     Volume:  97     ISSN:  0022-4251     ISO Abbreviation:  J. Reprod. Fertil.     Publication Date:  1993 Jan 
Date Detail:
Created Date:  1993-05-03     Completed Date:  1993-05-03     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0376367     Medline TA:  J Reprod Fertil     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  71-4     Citation Subset:  IM    
Veterinary Physiological Sciences, University of Saskatchewan, Saskatoon, Canada.
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MeSH Terms
Circadian Rhythm*
Luteal Phase / physiology*
Luteinizing Hormone / blood,  secretion*
Secretory Rate / physiology
Sheep / physiology*
Reg. No./Substance:
9002-67-9/Luteinizing Hormone

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

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