ISOLATION AND CHARACTERIZATION OF A RAT LUTEAL CDNA-ENCODING 20-ALPHA-HYDROXYSTEROID DEHYDROGENASE

We report the isolation and characterization of a full length cDNA enc oding rat 20 alpha hydroxysteroid dehydrogenase derived from rat corpu s luteum RNA. The predicted amino acid sequence of the protein encoded by the 20 alpha HSD clone is composed of 323 amino acids possessing a n approximate molecular weight of 37 kDa. The sequence of peptides der ived from the purified protein was found in the translated sequence of the open reading frame. cDNA and amino acid sequence indicate that th e rat ovarian 20 alpha HSD belongs to the aldo-keto reductase family o f enzymes. Northern analysis revealed a 1.2 Kb 20 alpha HSD mRNA in co rpora lutea undergoing luteolysis. Prolactin reduced markedly 20 alpha HSD mRNA expression. No signal was detected in other tissues examined , demonstrating the specific expression of this enzyme in the corpus l uteum. (C) 1994 Academic Press, Inc.