Steroid 21-hydroxylase in the kidney: demonstration of levels of messenger RNA which correlate with the level of activity.
Steroid 21-hydroxylase activity was assayed in low-speed supernatants prepared from whole cell homogenates of mouse and rat tissues. Kidney supernatants had an activity which was approximately 2-5% that of adrenal preparations while heart muscle was found to be without 21-hydroxylase activity. When the enzyme kinetics were characterized, both adrenal and kidney low-speed supernatants demonstrated saturation kinetics, but with very different Vmax and Km values. Using polymerase chain reaction amplification after reverse transcriptase synthesis of cDNA from isolated RNA (RT-PCR), we found low levels of mRNA for steroid 21-hydroxylase in mouse kidney, but none in heart muscle. Thus, extra-adrenal steroid 21-hydroxylase activity in the kidney may be mediated by the same enzyme as found in adrenals.
Lajic
S
S
Department of Woman and Child Health, Karolinska Institute, Karolinska Hospital, Stockholm, Sweden.
Eidsmo
L
L
Holst
M
M
D000311:Adrenal Glands / Q000201:enzymology; D000818:Animals; D001483:Base Sequence; D006900:Hydroxylation; D007668:Kidney / Q000201:enzymology*; D007700:Kinetics; D051379:Mice; D008969:Molecular Sequence Data; D009928:Organ Specificity; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013255:Steroid 21-Hydroxylase / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*
D012333:RNA, Messenger; D013255:Steroid 21-Hydroxylase