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Type: Journal article
Title: Short oestrous cycles in sheep during anoestrus involve defects in progesterone biosynthesis and luteal neovascularisation
Author: Brown, H.
Fabre Nys, C.
Cognié, J.
Scaramuzzi, R.
Citation: Reproduction, 2014; 147(3):357-367
Publisher: BioScientifica
Issue Date: 2014
ISSN: 1470-1626
Statement of
H M Brown, C Fabre Nys, J Cognié, and R J Scaramuzzi
Abstract: Anoestrous ewes can be induced to ovulate by the socio-sexual, 'ram effect'. However, in some ewes, the induced ovulation is followed by an abnormally short luteal phase causing a so-called 'short cycle'. The defect responsible for this luteal dysfunction has not been identified. In this study, we investigated ovarian and uterine factors implicated in male-induced short cycles in anoestrous ewes using a combined endocrine and molecular strategy. Before ovulation, we were able to detect a moderate loss of thecal expression of steroid acute regulatory protein (STAR) in ewes that had not received progesterone priming (which prevents short cycles). At and following ovulation, we were able to identify a significant loss of expression of genes coding key proteins involved in the biosynthesis of progesterone (STAR, CYP11A1 and HSD3B1 (HSD3B)) as well as genes coding proteins critical for vascular development during early luteal development (VEGFA and KDR (VEGFR2)), suggesting dysfunction in at least two pathways critical for normal luteal function. Furthermore, these changes were associated with a significant reduction of progesterone production and luteal weight. Additionally, we cast doubt on the proposed uterus-mediated effect of prostaglandin F2α (PGF2α) as a cause of short cycles by demonstrating the dysregulation of luteal expression of the PGF receptor, which mediates the luteal effects of PGF2α, and by finding no significant changes in the circulating concentrations of PGFM, the principal metabolite of PGF2α in ewes with short cycles. This study is the first of its kind to examine concurrently the endocrine and molecular events in the follicular and early luteal stages of the short cycle.
Keywords: Sheep
Corpus Luteum
Ovulation Induction
Estrous Cycle
Neovascularization, Physiologic
Cell Size
Time Factors
Sexual Behavior, Animal
Ovarian Follicle
Description: A French translation of this abstract is freely available at
Rights: © 2014 Society for Reproduction and Fertility
DOI: 10.1530/REP-13-0400
Appears in Collections:Aurora harvest 7
Paediatrics publications

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