PMID- 7734401
OWN - NLM
STAT- MEDLINE
DCOM- 19950602
LR  - 20190830
IS  - 0960-0760 (Print)
IS  - 0960-0760 (Linking)
VI  - 52
IP  - 4
DP  - 1995 Apr
TI  - Co-expression of two distinct isoforms of 11 beta-hydroxysteroid dehydrogenase in 
      the ovine placenta.
PG  - 337-43
AB  - We have previously described two distinct isoforms of 11 beta-hydroxysteroid 
      dehydrogenase (11 beta-HSD) with respect to enzymatic activity in the ovine liver 
      and kidney. To determine which isoform(s) is expressed in the ovine placenta, we 
      studied the characteristics of 11 beta-HSD activity in placental tissues 
      collected at days 140-143 of pregnancy. 11 beta-HSD activity was determined by a 
      radiometric conversion assay using cortisol and cortisone as physiological 
      substrates. At 100 nM cortisol, the placental 11 beta-HSD utilized NAD as 
      cofactor, but displayed preference for NADP at 10 microM cortisol. Kinetic 
      characteristics were examined in the presence of alternate cofactors, in order to 
      determine whether this difference in the cofactor requirement represents distinct 
      enzymes. With NAD as cofactor, the placental 11 beta-dehydrogenase had a Km (110 
      +/- 18 nM) compatible with the kidney enzyme, but displayed a Km (12 +/- 2 
      microM) similar/identical to the liver 11 beta-HSD when NADP was used. By 
      contrast, the placental 11-oxoreductase showed preference for NADPH regardless of 
      cortisone concentration. Kinetic analysis, using NADPH as cofactor, revealed a 
      single species of 11-oxoreductase activity with a Km of 4 +/- 0.9 microM and a 
      Vmax of 3.1 +/- 0.5 pmol/mg/min. Finally, since the NAD-dependent 11 beta-HSD in 
      the ovine placenta displayed similar/identical kinetic characteristics to the 
      enzyme described previously in the ovine kidney where a truncated 11 beta-HSD 
      transcript was identified, we have also determined whether this transcript is 
      expressed in the placenta by Northern blotting. It was found that the truncated 
      11 beta-HSD transcript was undetectable in the total RNA samples. These results 
      demonstrate that both liver- and kidney-types of 11 beta-HSD activities are 
      expressed in the ovine placenta, thus providing further evidence for the 
      existence of a NAD-dependent 11 beta-HSD distinct from the well-characterized 
      hepatic NADP-dependent enzyme. Furthermore, the lack of the truncated 11 beta-HSD 
      transcript in the placenta suggests that the NAD-dependent enzyme identified in 
      placenta and kidney is the product of a gene distinct from 11 beta-HSD.
FAU - Yang, K
AU  - Yang K
AD  - Lawson Research Institute, Department of Obstetrics and Gynecology, University of 
      Western Ontario, St Joseph's Health Centre, London, Canada.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - J Steroid Biochem Mol Biol
JT  - The Journal of steroid biochemistry and molecular biology
JID - 9015483
RN  - 0 (Isoenzymes)
RN  - 0 (RNA, Messenger)
RN  - 0U46U6E8UK (NAD)
RN  - 53-59-8 (NADP)
RN  - EC 1.1.- (Hydroxysteroid Dehydrogenases)
RN  - EC 1.1.1.146 (11-beta-Hydroxysteroid Dehydrogenases)
RN  - WI4X0X7BPJ (Hydrocortisone)
SB  - IM
MH  - 11-beta-Hydroxysteroid Dehydrogenases
MH  - Animals
MH  - Blotting, Northern
MH  - Female
MH  - Hydrocortisone/metabolism
MH  - Hydroxysteroid Dehydrogenases/*analysis/genetics/metabolism
MH  - Isoenzymes/*analysis/genetics/metabolism
MH  - NAD/metabolism
MH  - NADP/metabolism
MH  - Placenta/*enzymology
MH  - Pregnancy
MH  - RNA, Messenger/analysis
MH  - Sheep
EDAT- 1995/04/01 00:00
MHDA- 1995/04/01 00:01
CRDT- 1995/04/01 00:00
PHST- 1995/04/01 00:00 [pubmed]
PHST- 1995/04/01 00:01 [medline]
PHST- 1995/04/01 00:00 [entrez]
AID - 0960-0760(94)00179-P [pii]
AID - 10.1016/0960-0760(94)00179-p [doi]
PST - ppublish
SO  - J Steroid Biochem Mol Biol. 1995 Apr;52(4):337-43. doi: 
      10.1016/0960-0760(94)00179-p.