Human osteoblast-like cells express predominantly steroid 5α-reductase type 1

Sedika Issa, Doris Schnabel, Maritta Feix, Lutz Wolf, Hans Eckart Schaefer, David W. Russell, Hans Udo Schweikert

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

In previous studies we established that human bone and human osteoblast-like cells (hOB cells) cultured from bone express 5α-reductase (5α-R) activity, as demonstrated by the conversion of testosterone and androstenedione to their corresponding 5α-reduced metabolites, 5α-dihydrotestosterone (DHT) and 5α-androstanedione. Two 5α-R isozymes (types 1 and 2) have been identified in various tissues. As their nature in bone is unknown, we investigated which isozymes were expressed in first passage hOB cells cultured from bone specimens obtained from six donors (five women and one man). For comparison, 5α-reductase isozyme expression in genital skin fibroblasts cultured from foreskin of three males was determined. Pharmacological and biochemical studies using selective inhibitors of the 5α-R isozymes were performed, and gene expression was assessed by RT-PCR. In hOB cells, LY191704, a potent nonsteroidal selective inhibitor of 5α-R type 1, and the 4-azasteroid 17β-(N,N,-diethyl-carbamoyl)-4-methyl-4-aza-5α-androstan-3-one (a dual inhibitor of 5α-R types 1 and 2) inhibited 5α-R activity with a 50% inhibitory concentration (IC50) of approximately 4 nM. Finasteride, a selective inhibitor of 5α-R type 2, blocked 5α-R activity with an IC50 of approximately 60 nM. The IC50 of progesterone, a physiological substrate for 5α-R, was approximately 200 nM. In genital skin fibroblasts, LY191704 inhibited 5α-R with an IC50 of more than 5000 nM, whereas finasteride and 17β-(N,N,-diethyl-carbamoyl)-4-methyl-4-aza-5α-androstan-3-one effectively inhibited 5α-R with IC50 of approximately 4 nM. Experiments to determine 5α-reductase activity in homogenates of hOB cells as a function of pH showed very low activity at pH 5.5, but a broad shoulder of activity from pH 6.0-9.0, which was not inhibited by finasteride, but was nearly completely blocked by LY191704. RT-PCR revealed that 5α-R type 1 and 2 mRNAs were expressed in both bone and genital skin fibroblasts. Based on our pharmacological and biochemical studies, it appears that 5α-R activity in hOB cells is catalyzed predominantly by the type 1 rather than the type 2 isozyme. This expression pattern is in contrast to that in genital skin fibroblasts, where the activity of the type 2 isozyme prevails. As in most androgen target tissues DHT is biologically more active as an androgen than testosterone, DHT is formed in bone by 5α-R type 1 action from circulating testosterone, and bone cells also express the androgen receptor, local DHT production may play a physiological role in human bone homeostasis.

Original languageEnglish (US)
Pages (from-to)5401-5407
Number of pages7
JournalJournal of Clinical Endocrinology and Metabolism
Volume87
Issue number12
DOIs
StatePublished - Dec 1 2002

Fingerprint

Osteoblasts
Oxidoreductases
Bone
8-chloro-4-methyl-1,2,3,4,4a,5,6,10b-octahydrobenzo(f)quinolin-3(2H)-one
Steroids
Isoenzymes
Inhibitory Concentration 50
Bone and Bones
Dihydrotestosterone
Fibroblasts
Finasteride
Skin
Testosterone
Androgens
Azasteroids
Cultured Cells
Pharmacology
Tissue
Foreskin
Polymerase Chain Reaction

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology, Diabetes and Metabolism

Cite this

Human osteoblast-like cells express predominantly steroid 5α-reductase type 1. / Issa, Sedika; Schnabel, Doris; Feix, Maritta; Wolf, Lutz; Schaefer, Hans Eckart; Russell, David W.; Schweikert, Hans Udo.

In: Journal of Clinical Endocrinology and Metabolism, Vol. 87, No. 12, 01.12.2002, p. 5401-5407.

Research output: Contribution to journalArticle

Issa, Sedika ; Schnabel, Doris ; Feix, Maritta ; Wolf, Lutz ; Schaefer, Hans Eckart ; Russell, David W. ; Schweikert, Hans Udo. / Human osteoblast-like cells express predominantly steroid 5α-reductase type 1. In: Journal of Clinical Endocrinology and Metabolism. 2002 ; Vol. 87, No. 12. pp. 5401-5407.
@article{d6335f5909c947a09b7bb4cb5e8da274,
title = "Human osteoblast-like cells express predominantly steroid 5α-reductase type 1",
abstract = "In previous studies we established that human bone and human osteoblast-like cells (hOB cells) cultured from bone express 5α-reductase (5α-R) activity, as demonstrated by the conversion of testosterone and androstenedione to their corresponding 5α-reduced metabolites, 5α-dihydrotestosterone (DHT) and 5α-androstanedione. Two 5α-R isozymes (types 1 and 2) have been identified in various tissues. As their nature in bone is unknown, we investigated which isozymes were expressed in first passage hOB cells cultured from bone specimens obtained from six donors (five women and one man). For comparison, 5α-reductase isozyme expression in genital skin fibroblasts cultured from foreskin of three males was determined. Pharmacological and biochemical studies using selective inhibitors of the 5α-R isozymes were performed, and gene expression was assessed by RT-PCR. In hOB cells, LY191704, a potent nonsteroidal selective inhibitor of 5α-R type 1, and the 4-azasteroid 17β-(N,N,-diethyl-carbamoyl)-4-methyl-4-aza-5α-androstan-3-one (a dual inhibitor of 5α-R types 1 and 2) inhibited 5α-R activity with a 50{\%} inhibitory concentration (IC50) of approximately 4 nM. Finasteride, a selective inhibitor of 5α-R type 2, blocked 5α-R activity with an IC50 of approximately 60 nM. The IC50 of progesterone, a physiological substrate for 5α-R, was approximately 200 nM. In genital skin fibroblasts, LY191704 inhibited 5α-R with an IC50 of more than 5000 nM, whereas finasteride and 17β-(N,N,-diethyl-carbamoyl)-4-methyl-4-aza-5α-androstan-3-one effectively inhibited 5α-R with IC50 of approximately 4 nM. Experiments to determine 5α-reductase activity in homogenates of hOB cells as a function of pH showed very low activity at pH 5.5, but a broad shoulder of activity from pH 6.0-9.0, which was not inhibited by finasteride, but was nearly completely blocked by LY191704. RT-PCR revealed that 5α-R type 1 and 2 mRNAs were expressed in both bone and genital skin fibroblasts. Based on our pharmacological and biochemical studies, it appears that 5α-R activity in hOB cells is catalyzed predominantly by the type 1 rather than the type 2 isozyme. This expression pattern is in contrast to that in genital skin fibroblasts, where the activity of the type 2 isozyme prevails. As in most androgen target tissues DHT is biologically more active as an androgen than testosterone, DHT is formed in bone by 5α-R type 1 action from circulating testosterone, and bone cells also express the androgen receptor, local DHT production may play a physiological role in human bone homeostasis.",
author = "Sedika Issa and Doris Schnabel and Maritta Feix and Lutz Wolf and Schaefer, {Hans Eckart} and Russell, {David W.} and Schweikert, {Hans Udo}",
year = "2002",
month = "12",
day = "1",
doi = "10.1210/jc.2001-011902",
language = "English (US)",
volume = "87",
pages = "5401--5407",
journal = "Journal of Clinical Endocrinology and Metabolism",
issn = "0021-972X",
publisher = "The Endocrine Society",
number = "12",

}

TY - JOUR

T1 - Human osteoblast-like cells express predominantly steroid 5α-reductase type 1

AU - Issa, Sedika

AU - Schnabel, Doris

AU - Feix, Maritta

AU - Wolf, Lutz

AU - Schaefer, Hans Eckart

AU - Russell, David W.

AU - Schweikert, Hans Udo

PY - 2002/12/1

Y1 - 2002/12/1

N2 - In previous studies we established that human bone and human osteoblast-like cells (hOB cells) cultured from bone express 5α-reductase (5α-R) activity, as demonstrated by the conversion of testosterone and androstenedione to their corresponding 5α-reduced metabolites, 5α-dihydrotestosterone (DHT) and 5α-androstanedione. Two 5α-R isozymes (types 1 and 2) have been identified in various tissues. As their nature in bone is unknown, we investigated which isozymes were expressed in first passage hOB cells cultured from bone specimens obtained from six donors (five women and one man). For comparison, 5α-reductase isozyme expression in genital skin fibroblasts cultured from foreskin of three males was determined. Pharmacological and biochemical studies using selective inhibitors of the 5α-R isozymes were performed, and gene expression was assessed by RT-PCR. In hOB cells, LY191704, a potent nonsteroidal selective inhibitor of 5α-R type 1, and the 4-azasteroid 17β-(N,N,-diethyl-carbamoyl)-4-methyl-4-aza-5α-androstan-3-one (a dual inhibitor of 5α-R types 1 and 2) inhibited 5α-R activity with a 50% inhibitory concentration (IC50) of approximately 4 nM. Finasteride, a selective inhibitor of 5α-R type 2, blocked 5α-R activity with an IC50 of approximately 60 nM. The IC50 of progesterone, a physiological substrate for 5α-R, was approximately 200 nM. In genital skin fibroblasts, LY191704 inhibited 5α-R with an IC50 of more than 5000 nM, whereas finasteride and 17β-(N,N,-diethyl-carbamoyl)-4-methyl-4-aza-5α-androstan-3-one effectively inhibited 5α-R with IC50 of approximately 4 nM. Experiments to determine 5α-reductase activity in homogenates of hOB cells as a function of pH showed very low activity at pH 5.5, but a broad shoulder of activity from pH 6.0-9.0, which was not inhibited by finasteride, but was nearly completely blocked by LY191704. RT-PCR revealed that 5α-R type 1 and 2 mRNAs were expressed in both bone and genital skin fibroblasts. Based on our pharmacological and biochemical studies, it appears that 5α-R activity in hOB cells is catalyzed predominantly by the type 1 rather than the type 2 isozyme. This expression pattern is in contrast to that in genital skin fibroblasts, where the activity of the type 2 isozyme prevails. As in most androgen target tissues DHT is biologically more active as an androgen than testosterone, DHT is formed in bone by 5α-R type 1 action from circulating testosterone, and bone cells also express the androgen receptor, local DHT production may play a physiological role in human bone homeostasis.

AB - In previous studies we established that human bone and human osteoblast-like cells (hOB cells) cultured from bone express 5α-reductase (5α-R) activity, as demonstrated by the conversion of testosterone and androstenedione to their corresponding 5α-reduced metabolites, 5α-dihydrotestosterone (DHT) and 5α-androstanedione. Two 5α-R isozymes (types 1 and 2) have been identified in various tissues. As their nature in bone is unknown, we investigated which isozymes were expressed in first passage hOB cells cultured from bone specimens obtained from six donors (five women and one man). For comparison, 5α-reductase isozyme expression in genital skin fibroblasts cultured from foreskin of three males was determined. Pharmacological and biochemical studies using selective inhibitors of the 5α-R isozymes were performed, and gene expression was assessed by RT-PCR. In hOB cells, LY191704, a potent nonsteroidal selective inhibitor of 5α-R type 1, and the 4-azasteroid 17β-(N,N,-diethyl-carbamoyl)-4-methyl-4-aza-5α-androstan-3-one (a dual inhibitor of 5α-R types 1 and 2) inhibited 5α-R activity with a 50% inhibitory concentration (IC50) of approximately 4 nM. Finasteride, a selective inhibitor of 5α-R type 2, blocked 5α-R activity with an IC50 of approximately 60 nM. The IC50 of progesterone, a physiological substrate for 5α-R, was approximately 200 nM. In genital skin fibroblasts, LY191704 inhibited 5α-R with an IC50 of more than 5000 nM, whereas finasteride and 17β-(N,N,-diethyl-carbamoyl)-4-methyl-4-aza-5α-androstan-3-one effectively inhibited 5α-R with IC50 of approximately 4 nM. Experiments to determine 5α-reductase activity in homogenates of hOB cells as a function of pH showed very low activity at pH 5.5, but a broad shoulder of activity from pH 6.0-9.0, which was not inhibited by finasteride, but was nearly completely blocked by LY191704. RT-PCR revealed that 5α-R type 1 and 2 mRNAs were expressed in both bone and genital skin fibroblasts. Based on our pharmacological and biochemical studies, it appears that 5α-R activity in hOB cells is catalyzed predominantly by the type 1 rather than the type 2 isozyme. This expression pattern is in contrast to that in genital skin fibroblasts, where the activity of the type 2 isozyme prevails. As in most androgen target tissues DHT is biologically more active as an androgen than testosterone, DHT is formed in bone by 5α-R type 1 action from circulating testosterone, and bone cells also express the androgen receptor, local DHT production may play a physiological role in human bone homeostasis.

UR - http://www.scopus.com/inward/record.url?scp=0036920778&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0036920778&partnerID=8YFLogxK

U2 - 10.1210/jc.2001-011902

DO - 10.1210/jc.2001-011902

M3 - Article

VL - 87

SP - 5401

EP - 5407

JO - Journal of Clinical Endocrinology and Metabolism

JF - Journal of Clinical Endocrinology and Metabolism

SN - 0021-972X

IS - 12

ER -