Effects of cycle stage on regionalised galanin, galanin receptors 1-3, GnRH and GnRH receptor mRNA expression in the ovine hypothalamus

Whitelaw, C.M., Robinson, J.E. , Hastie, P.M. , Padmanabhan, V. and Evans, N.P. (2012) Effects of cycle stage on regionalised galanin, galanin receptors 1-3, GnRH and GnRH receptor mRNA expression in the ovine hypothalamus. Journal of Endocrinology, 212(3), pp. 353-361. (doi: 10.1530/JOE-11-0352)

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Abstract

The neurotransmitter galanin has been implicated in the steroidogenic regulation of reproduction based on work mainly conducted in rodents. This study investigated the temporal changes in the expression of galanin and its 3 receptor isoforms and GnRH and GnRHR mRNA in specific hypothalamic nuclei known to be involved in the regulation of reproductive cyclicity, namely the medial pre-optic area (mPOA), the rostral mPOA/ OVLT, the paraventricular nucleus (PVN) and the arcuate nucleus (ARC) using an ovine model. Following synchronisation of their oestrous cycles, tissues were collected from ewes at 5 time points, the early, mid and late follicular phase and the early and mid luteal phase. The results indicated significant differences in regional expression of most of the genes studied with galanin mRNA expression being highest during the mid follicular phase at the start of the GnRH/LH surge and the expression of the three galanin receptor isoforms and GnRH and its receptor highest during the luteal phase. These findings are consistent with a role for galanin in the positive feedback effects of oestradiol on GnRH secretion and a role for progesterone induced changes in the pattern of expression of galanin receptors in the regulation of the timing of oestradiol positive feedback through increased sensitivity of galanin sensitive systems to secreted galanin.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Robinson, Dr Jane and Hastie, Professor Peter and Whitelaw, Mrs Christine and Evans, Professor Neil
Authors: Whitelaw, C.M., Robinson, J.E., Hastie, P.M., Padmanabhan, V., and Evans, N.P.
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
College of Medical Veterinary and Life Sciences > School of Veterinary Medicine
Journal Name:Journal of Endocrinology
Publisher:BioScientifica Ltd.
ISSN:0022-0795
ISSN (Online):1479-6805
Published Online:12 December 2011

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