Expression of genes for Kisspeptin (KISS1), Neurokinin B (TAC3), Prodynorphin (PDYN), and gonadotropin inhibitory hormone (RFRP) across natural puberty in ewes. Issue 5 (13th March 2020)

• Record Type: Journal Article
• Authors: Li, Qun; Smith, Jeremy T.; Henry, Belinda; Rao, Alexandra; Pereira, Alda; Clarke, Iain J.
• Is Part Of: Physiological reports. Volume 8:Issue 5(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-03-13
• Subjects: gonadotropin releasing hormone -- gonadotropins -- hypothalamus; Physiology -- Periodicals; 571
• DOI: 10.14814/phy2.14399
• Languages: English
• ISSNs: 2051-817X

Abstract

Abstract: Expression of particular genes in hypothami of ewes was measured across the natural pubertal transition by in situ hybridization. The ewes were allocated to three groups ( n = 4); prepubertal, postpubertal and postpubertally gonadectomized (GDX). Prepubertal sheep were euthanized at 20 weeks of age and postpubertal animals at 32 weeks. GDX sheep were also euthanized at 32 weeks, 1 week after surgery. Expression of KISS1, TAC3, PDYN in the arcuate nucleus (ARC), RFRP in the dorsomedial hypothalamus and GNRH1 in the preoptic area was quantified on a cellular basis. KISS1R expression by GNRH1 cells was quantified by double‐label in situ hybridization. Across puberty, detectable KISS1 cell number increased in the caudal ARC and whilst PDYN cell numbers were low, numbers increased in the rostral ARC. TAC3 expression did not change but RFRP expression/cell was reduced across puberty. There was no change across puberty in the number of GNRH1 cells that expressed the kisspeptin receptor ( KISS1R ). GDX shortly after puberty did not increase expression of any of the genes of interest. We conclude that KISS1 expression in the ARC increases during puberty in ewes and this may be a causative factor in the pubertal activation of the reproductive axis. A reduction in expression of RFRP may be a factor in the onset of puberty, removing negative tone on GNRH1 cells. The lack of changes in expression of genes following GDX suggest that the effects of gonadal hormones may differ in young and mature animals. Abstract : Kisspeptin is a major regulator of GnRH secretion and its function has been shown to be mandatory for pubertal transition. In this article, we examined the expression of KISS1, TAC3, PDYN, RFRP, GNRH1 and KISS1R in specific areas of hypothalamus across puberty in ewe. We conclude that KISS1 expression in the ARC increases during puberty in ewes and this may be a causative factor in the pubertal activation of the reproductive axis and a reduction in expression of RFRP may be a factor in the onset of puberty, removing negative tone on GNRH1 cells.