1. Seasonal changes in luteal progesterone concentration and mRNA expressions of progesterone synthesis-related proteins in the corpus luteum of mares.
- Author
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Kozai K, Hojo T, Takahashi M, Acosta TJ, Nambo Y, and Okuda K
- Subjects
- 3-Hydroxysteroid Dehydrogenases genetics, 3-Hydroxysteroid Dehydrogenases metabolism, Abattoirs, Animals, Animals, Inbred Strains, Canada, Cholesterol Side-Chain Cleavage Enzyme genetics, Cholesterol Side-Chain Cleavage Enzyme metabolism, Corpus Luteum cytology, Female, Japan, Phosphoproteins genetics, Phosphoproteins metabolism, Progesterone metabolism, RNA, Messenger metabolism, Receptors, LH genetics, Receptors, LH metabolism, Seasons, Corpus Luteum metabolism, Gene Expression Regulation, Horses physiology, Luteal Phase metabolism, Progesterone biosynthesis
- Abstract
Although circulating progesterone (P₄) levels tend to change with the season, little is known about the seasonal changes of P₄ synthesis-related proteins in the corpus luteum (CL) of mares. To examine these changes, seventy-four ovaries containing a CL were collected from Anglo-Norman mares at a local abattoir in Kumamoto, Japan (~N32°), five times during one year. The stages of the CLs were classified as early, mid and regressed by macroscopic observation of the CL and follicles. The mid CL, which had the highest P₄ concentration, was used to evaluate the seasonal changes in P₄ synthesis. The luteal P₄ concentration and mRNA expression of luteinizing hormone receptor (LHCGR) were lowest during early winter and highest during late winter. The mRNA expressions of steroidogenic acute regulatory protein (StAR), P450 cholesterol side-chain cleavage enzyme (P450scc) and 3β-hydroxysteroid dehydrogenase/Δ5-Δ4 isomerase (3β-HSD) were lowest during early winter and increased during late winter. These results suggest that P₄ synthesis in the CL is affected by the seasonal changes in the mRNA expressions of P₄ synthesis-related proteins in mares.
- Published
- 2012
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