The subcellular distribution of steroidogenic enzymes has so far been studied mostly in classical endocrine glands and in the placenta. In the peripheral intracrine organs which synthesize sex steroids there is no indication about the organelles which contain the enzymes involved in steroid biosynthesis. We have thus investigated the subcellular localization of two enzymes involved in the production of sex steroids, namely 3beta-hydroxysteroid dehydrogenase (3beta-HSD) and type 5 17beta-hydroxysteroid dehydrogenase (17beta-HSD). Using specific antibodies to these enzymes, we conducted immunoelectron microscopic studies in two peripheral tissues, namely the human prostate and mammary gland. In the prostate, immunolabelling for both 3beta-HSD and type 5 17beta-HSD was detected in the basal cells of the tube-alveoli as well as in fibroblasts and endothelial cells lining the blood vessels. In all the labelled cell types, the gold particles were distributed throughout the cytoplasm. No obvious association with any specific organelle could be observed, although some concentration of gold particles was occasionally found over bundles of microfilaments. In mammary gland sections immunolabelled for 3beta-HSD or type 5 17beta-HSD localization, labelling was observed in the cytoplasm of the secretory epithelial cells in both the acini and terminal ducts. Immunolabelling was also found in the endothelial cells as well as in fibroblasts in stroma and blood vessels. The gold particles were not detected over any organelles, except with the occasional accumulation of gold particles over microfilaments. The present data on the localization of two steroidogenic enzymes leading to the synthesis of testosterone indicate that these enzymes are located not only in epithelial cells but also in stromal and endothelial cells in both tissues studied. The absence of any association of the enzymes with membrane-bound organelles appears as a common finding in the reactive cell types of two peripheral tissues.

This article has been cited by other articles:

				J. M Day, H. J Tutill, A. Purohit, and M. J Reed Design and validation of specific inhibitors of 17{beta}-hydroxysteroid dehydrogenases for therapeutic application in breast and prostate cancer, and in endometriosis Endocr. Relat. Cancer, September 1, 2008; 15(3): 665 - 692. [Abstract] [Full Text] [PDF]

				S. A. Hall, S. T. Page, T. G. Travison, R. B. Montgomery, C. L. Link, and J. B. McKinlay Do Statins Affect Androgen Levels in Men? Results from the Boston Area Community Health Survey Cancer Epidemiol. Biomarkers Prev., August 1, 2007; 16(8): 1587 - 1594. [Abstract] [Full Text] [PDF]

				D. R. Bauman, S. Steckelbroeck, D. M. Peehl, and T. M. Penning Transcript Profiling of the Androgen Signal in Normal Prostate, Benign Prostatic Hyperplasia, and Prostate Cancer Endocrinology, December 1, 2006; 147(12): 5806 - 5816. [Abstract] [Full Text] [PDF]

				K-M Fung, E N S Samara, C Wong, A Metwalli, R Krlin, B Bane, C Z Liu, J T Yang, J V Pitha, D J Culkin, et al. Increased expression of type 2 3{alpha}-hydroxysteroid dehydrogenase/type 5 17{beta}-hydroxysteroid dehydrogenase (AKR1C3) and its relationship with androgen receptor in prostate carcinoma. Endocr. Relat. Cancer, March 1, 2006; 13(1): 169 - 180. [Abstract] [Full Text] [PDF]

				F Labrie, V Luu-The, A Belanger, S-X Lin, J Simard, G Pelletier, and C Labrie Is dehydroepiandrosterone a hormone? J. Endocrinol., November 1, 2005; 187(2): 169 - 196. [Abstract] [Full Text] [PDF]

				J Miao, K-W Chan, G G Chen, S-Y Chun, N-S Xia, J Y H Chan, and N S Panesar Blocking BRE expression in Leydig cells inhibits steroidogenesis by down-regulating 3{beta}-hydroxysteroid dehydrogenase J. Endocrinol., June 1, 2005; 185(3): 507 - 517. [Abstract] [Full Text] [PDF]

				R. T. Chatterton Jr., A. S. Geiger, E. T. Mateo, I. B. Helenowski, and P. H. Gann Comparison of Hormone Levels in Nipple Aspirate Fluid of Pre- and Postmenopausal Women: Effect of Oral Contraceptives and Hormone Replacement J. Clin. Endocrinol. Metab., March 1, 2005; 90(3): 1686 - 1691. [Abstract] [Full Text] [PDF]

				D. R. Bauman, S. I. Rudnick, L. M. Szewczuk, Y. Jin, S. Gopishetty, and T. M. Penning Development of Nonsteroidal Anti-Inflammatory Drug Analogs and Steroid Carboxylates Selective for Human Aldo-Keto Reductase Isoforms: Potential Antineoplastic Agents That Work Independently of Cyclooxygenase Isozymes Mol. Pharmacol., January 1, 2005; 67(1): 60 - 68. [Abstract] [Full Text] [PDF]

				F. Labrie, V. Luu-The, C. Labrie, A. Belanger, J. Simard, S.-X. Lin, and G. Pelletier Endocrine and Intracrine Sources of Androgens in Women: Inhibition of Breast Cancer and Other Roles of Androgens and Their Precursor Dehydroepiandrosterone Endocr. Rev., April 1, 2003; 24(2): 152 - 182. [Abstract] [Full Text] [PDF]