Cloning of cDNA encoding an NAD(+)-dependent isoform of 11 beta-hydroxysteroid dehydrogenase in sheep kidney.
11 beta-Hydroxysteroid dehydrogenase (11-HSD) catalyzes the conversion of cortisol to cortisone and corticosterone to 11-dehydrocorticosterone. This activity may be required to confer normal ligand specificity upon the mineralocorticoid receptor. Although an isozyme of 11-HSD was previously isolated from rat liver, a different isozyme is apparently expressed in mineralocorticoid target tissues. We isolated a sheep kidney cDNA clone encoding this isozyme by expression screening using Xenopus oocytes. The cDNA is 1.8 kb in length and encodes a protein of 427 amino acid residues with a predicted M(r) of 46,700. When expressed in oocytes, this enzyme functions as an NAD(+)-dependent 11 beta-hydrogenase with very high affinity for steroids, but it has no detectable reductase activity. It is 37% identical in amino acid sequence to an NAD(+)-dependent isozyme of 17 beta-hydroxysteroid dehydrogenase, but only 20% identical to the NADP(+)-dependent liver isozyme of 11-HSD. It is expressed at high levels in the kidney and adrenal and at lower levels in the colon. The corresponding gene is present in a single copy in the sheep genome. In humans, this gene is a candidate locus for the syndrome of apparent mineralocorticoid excess, a form of hypertension postulated to result from 11-HSD deficiency in mineralocorticoid target tissues.
Agarwal
A K
AK
Division of Pediatric Endocrinology, University of Texas Southwestern Medical Center, Dallas 75235, USA.
Mune
T
T
Monder
C
C
White
P C
PC
D042842:11-beta-Hydroxysteroid Dehydrogenases; D015067:17-Hydroxysteroid Dehydrogenases / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics*; D005815:Genetic Code; D006801:Humans; D006913:Hydroxysteroid Dehydrogenases / Q000235:genetics*; D007527:Isoenzymes / Q000235:genetics*; D007668:Kidney / Q000201:enzymology*; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D012756:Sheep; D014981:Xenopus
D018076:DNA, Complementary; D007527:Isoenzymes; D015067:17-Hydroxysteroid Dehydrogenases; D006913:Hydroxysteroid Dehydrogenases; D042842:11-beta-Hydroxysteroid Dehydrogenases; C032690:3-alpha-(17-beta)-hydroxysteroid dehydrogenase (NAD(+))