Endocrinology, Vol 137, 2718-2730, Copyright © 1996 by Endocrine Society

ARTICLES

Ontogeny of 5 alpha-reductase (type 1) messenger ribonucleic acid expression in rat brain: early presence in germinal zones

ME Lauber and W Lichtensteiger
Institute of Pharmacology, University of Zurich, Switzerland.

The physiological significance of androgens and neurosteroids in the development of the central nervous system (CNS) is still unclear. One way to address this question is to examine the regional and developmental expression of enzymes involved in the biosynthesis of these compounds. As 5alpha-reduction is a key step in the formation of dihydrotestosterone and some neurosteroids, we investigated the distribution of 5alpha-reductase (type 1) messenger RNA (mRNA) in the brain of fetuses and offspring of time pregnant Long-Evan rats by means of in situ hybridization. Our results indicate that during ontogeny, 5alpha-reductase mRNA is expressed in three distinct patterns. 1) During late embryonic and fetal development, on gestational days 12-18, specific 5alpha-reductase mRNA was detected in germinal and ventricular zones of the developing CNS. Specific labeling was also detected in the liver and certain ganglia, such as those of the trigeminal and spinal nerves. 2) During late fetal and early postnatal development, 5alpha- reductase mRNA levels in the ventricular zones gradually decreased, but specific mRNA newly appeared in differentiating regions of the brain, such as the cortical plate and the thalamus. 3) On postnatal day 15 and in adult animals, low levels of 5alpha-reductase mRNA were detected in typical white matter structures, such as optical chiasm, lateral olfactory tract, and corpus callosum. Expression of 5alpha-reductase mRNA in germinal zones and differentiating fields of the pre- and early postnatal rat CNS has not been described; this suggests that 5alpha- reductase might serve a function in general aspects of brain development, e.g. proliferation and differentiation. As several types of steroid hormones can serve as substrates for 5alpha-reductase, it remains to be elucidated which metabolite(s) mediates the possible actions of the_ enzyme in CNS development.

This article has been cited by other articles:

				L. Liu, J. Wang, L. Zhao, J. Nilsen, K. McClure, K. Wong, and R. D. Brinton Progesterone Increases Rat Neural Progenitor Cell Cycle Gene Expression and Proliferation Via Extracellularly Regulated Kinase and Progesterone Receptor Membrane Components 1 and 2 Endocrinology, July 1, 2009; 150(7): 3186 - 3196. [Abstract] [Full Text] [PDF]

				P. J. Brunton, A. J. McKay, T. Ochedalski, A. Piastowska, E. Rebas, A. Lachowicz, and J. A. Russell Central Opioid Inhibition of Neuroendocrine Stress Responses in Pregnancy in the Rat Is Induced by the Neurosteroid Allopregnanolone J. Neurosci., May 20, 2009; 29(20): 6449 - 6460. [Abstract] [Full Text] [PDF]

				J M Torres and E Ortega Steroid 5{alpha}-reductase isozymes in the adult female rat brain: central role of dihydrotestosterone. J. Mol. Endocrinol., April 1, 2006; 36(2): 239 - 245. [Abstract] [Full Text] [PDF]

				J. M. Wang, P. B. Johnston, B. G. Ball, and R. D. Brinton The Neurosteroid Allopregnanolone Promotes Proliferation of Rodent and Human Neural Progenitor Cells and Regulates Cell-Cycle Gene and Protein Expression J. Neurosci., May 11, 2005; 25(19): 4706 - 4718. [Abstract] [Full Text] [PDF]

				J. M. TORRES and E. ORTEGA Differential regulation of steroid 5{alpha}-reductase isozymes expression by androgens in the adult rat brain FASEB J, August 1, 2003; 17(11): 1428 - 1433. [Abstract] [Full Text] [PDF]

				N. A. Compagnone and S. H. Mellon Dehydroepiandrosterone: A potential signalling molecule for neocortical organization during development PNAS, April 14, 1998; 95(8): 4678 - 4683. [Abstract] [Full Text] [PDF]