title: Rat kidney 25-hydroxyvitamin D3 1 alpha- and 24-hydroxylases: evidence for two distinct gene products.
abstract: Total RNA was isolated from kidneys of Sprague-Dawley rats. Oligo (dT)-primed single-stranded cDNA was obtained by the reverse transcriptase reaction from which a 285 bp cDNA probe coding for 25-hydroxyvitamin D3-24-hydroxylase [25(OH)D3-24-OHase] was generated by the polymerase chain reaction. Northern blotting performed with kidney poly (A)+ RNA isolated from rats (1) fed a standard diet, (2) depleted in D3 and hypocalcemic, and (3) fed a standard diet and injected intraperitoneally with 50,000 IU of vitamin D3 for 5 days showed that the transcript for 24-OHase was weakly expressed in control, and highly induced in vitamin D3-treated animals. No transcript could be elicited in vitamin D-depleted hypocalcemic animals in which 25(OH)D3-1 alpha-OHase was maximally induced. The data show that 24-OHase is independently regulated of 1 alpha-OHase, strongly suggestive of the enzymes being encoded by two distinct genes.
authors.affiliation: Genetics Unit, Shriners Hospital, Montreal, Quebec, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Arabian
authors.forename: J
authors.initials: J
authors.lastname: Grover
authors.forename: M G
authors.initials: MG
authors.lastname: Barré
authors.forename: E E
authors.initials: EE
authors.lastname: Delvin
mesh_terms: D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D002112:Calcifediol / Q000097:blood; D002118:Calcium / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D004247:DNA; D007668:Kidney / Q000201:enzymology*; D011061:Poly A / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger; D051381:Rats; D017207:Rats, Sprague-Dawley; D013250:Steroid Hydroxylases / Q000235:genetics* / Q000378:metabolism; D014807:Vitamin D / Q000378:metabolism; D065668:Vitamin D3 24-Hydroxylase
chemical_list: D012333:RNA, Messenger; D014807:Vitamin D; D011061:Poly A; D012313:RNA; D004247:DNA; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D065668:Vitamin D3 24-Hydroxylase; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase; D002112:Calcifediol; D002118:Calcium