Carbonyl reductase is an NADPH-dependent, cytosolic enzyme that is widely distributed in human and animal tissues. This particular cDNA fragment, isolated by differential display RT-PCR, is uniquely expressed in the rat ovary along with at least three other isoforms (NCBI Accession Numbers AF181955, AF181956, and AF181957) during the ovulatory process.
General function
Metabolism, Enzyme, Oxidoreductase
Comment
Actually, carbonyl reductase is a group of monomeric aldo-keto reductases with broad specificity for converting carbonyl compounds such as aromatic, aliphatic, and cyclic aldehydes and ketones into alcohols (Nakajin et al., 1997).
Cellular localization
Cytoplasmic
Comment
Ovarian function
Ovulation
Comment
The function of carbonyl reductase gene expression during ovulation has not been established (Espey et al., 2000). Studies in other biological systems have led to the hypothesis that aldo-keto reductases may have a physiologic role in the detoxification of steroids, prostanoids, and pterins in tissues where their endogenous production is excessive (Wirth and Wermuth, 1992) Therefore, it is possible that carbonyl reductase is metabolizing ovarian progesterone and prostaglandins that are known to increase substantially at the time of ovulation.
Expression regulated by
LH
Comment
Treatment of PMSG-primed immature rats with hCG resulted in a 14-fold increase in ovarian carbonyl reductase mRNa at 8 h after hCG, i.e., at 8 hours into the ovulatory process (Espey et al., 2000).
Ovarian localization
Theca, Stromal cells
Comment
Localization was determined by in situ hybridization using a cDNA clone obtained by differential display RT-PCR (Espey et al., 2000).
Follicle stages
Preovulatory
Comment
Ovarian carbonyl reductase gene expression began to increase by 2 hours after hCG administration to the rats. It reached a peak at 8 hours after hCG, and then it declined to pre-hCG control levels by 24 hours after hCG (Espey et al., 2000).