Expression of fos and in vivo median eminence release of LHRH identifies an active role for preoptic area kisspeptin neurons in synchronized surges of LH and LHRH in the ewe

Gloria E. Hoffman, Wei Wei Le, Isabelle Franceschini, Alain Caraty, Juan P. Advis

Research output: Contribution to journalArticle

56 Scopus citations

Abstract

We tested the working hypothesis that Fos will identify the critical population of kisspeptin neurons that accompanies the LHRH surge using a synchronized follicular phase model in intact cycling ewes. The model generates an LH surge that starts within a defined 2-h window in a 20-d synchronized cycle. With a modified push-pull cannula in vivo LHRH release from the median eminence was sampled in luteal phase ewes, ewes undergoing an LH surge for 2-4 h, and postsurge animals whose LH surge peaked 10-12 h earlier. In vivo release of LHRH was lower in the luteal and follicular phases than in animals undergoing an LH surge (P < 0.01); it fell to presurge levels after the LH surge. Ewes killed 2-4 h after the surge started, expressed Fos in a large portion of preoptic area (POA) kisspeptin (53.90 ± 4.69%, P < 0.01) and LHRH neurons (48.20 ± 4.49%, P < 0.0001) compared with animals euthanized at any of the other times tested (under <5% of the cells activated). Little Fos activation (under5%)wasobserved during any of the times sampled in arcuate (Arc) kisspeptin neurons. The relationship between the number of LHRH neurons and the POA kisspeptin neurons stimulated showed a striking positive correlation with r2 = 0.68, P = 0.0003, reinforcing the evidence that POA kisspeptin neurons actively participate in the stimulation of LHRH surges.

Original languageEnglish (US)
Pages (from-to)214-222
Number of pages9
JournalEndocrinology
Volume152
Issue number1
DOIs
StatePublished - Jan 2011

All Science Journal Classification (ASJC) codes

  • Endocrinology

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