title: Role of 11β-OH-C(19) and C(21) steroids in the coupling of 11β-HSD1 and 17β-HSD3 in regulation of testosterone biosynthesis in rat Leydig cells.
abstract: Here we describe further experiments to support our hypothesis that bidirectional 11β-HSD1-dehydrogenase in Leydig cells is a NADP(H) regenerating system. In the absence of androstenedione (AD), substrate for 17β-HSD3, incubation of Leydig cells with corticosterone (B) or several C(19)- and C(21)-11β-OH-steroids, in the presence of [(3)H]-11-dehydro-corticosterone (A), stimulated 11β-HSD1-reductase activity. However, in presence of 30 μM AD, testosterone (Teso) synthesis is stimulated from 4 to 197 picomole/25,000 cells/30 min and concomitantly inhibited 11β-HSD1-reductase activity, due to competition for the common cofactor NADPH needed for both reactions. Testo production was further significantly increased (p<0.05) to 224-267 picomole/25,000 cells/30 min when 10 μM 11β-OH-steroids (in addition to 30 μM AD) were also included. Similar results were obtained in experiments conducted with lower concentrations of AD (5 μM), and B or A (500 nM). Incubations of 0.3-6.0 μM of corticosterone (plus or minus 30 μM AD) were then performed to test the effectiveness of 17β-HSD3 as a possible NADP(+) regenerating system. In the absence of AD, increasing amounts (3-44 pmol/25,000 cells/30 min) of 11-dehydro-corticosterone were produced with increasing concentrations of corticosterone in the medium. When 30 μM AD was included, the rate of 11-dehydro-corticosterone formation dramatically increased 1.3-5-fold producing 4-210 pmol/25,000 cells/30 min of 11-dehydro-corticosterone. We conclude that 11β-HSD1 is enzymatically coupled to 17β-HSD3, utilizing NADPH and NADP in intermeshed regeneration systems.
authors: Department of Pathology and Laboratory Medicine, The Miriam Hospital, Brown University School of Medicine, 164, Summit Avenue, Providence, RI 02906, United States. slatif@lifespan.org
authors: Syed A
authors: SA
authors: Latif
authors: Mae
authors: M
authors: Shen
authors: Ren-Shan
authors: RS
authors: Ge
authors: Chantal M
authors: CM
authors: Sottas
authors: Matthew P
authors: MP
authors: Hardy
authors: David J
authors: DJ
authors: Morris
mesh_terms: D043205:11-beta-Hydroxysteroid Dehydrogenase Type 1 / Q000378:metabolism*; D015067:17-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D000735:Androstenedione / Q000494:pharmacology; D000818:Animals; D003345:Corticosterone / Q000494:pharmacology; D007985:Leydig Cells / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D013256:Steroids / Q000737:chemistry* / Q000494:pharmacology*; D013739:Testosterone / Q000096:biosynthesis*
chemical_list: D013256:Steroids; D013739:Testosterone; D000735:Androstenedione; D009249:NADP; D015067:17-Hydroxysteroid Dehydrogenases; C476565:17beta-hydroxysteroid dehydrogenase type 3; D043205:11-beta-Hydroxysteroid Dehydrogenase Type 1; D003345:Corticosterone