HIGH-DOSE ANABOLIC-ANDROGENIC STEROIDS MODULATE CONCENTRATIONS OF NERVE GROWTH-FACTOR AND EXPRESSION OF ITS LOW-AFFINITY RECEPTOR (P75-NGFR) IN MALE-RAT BRAIN

The effects of treatment with a high dose of nandrolone or testosteron e on nerve growth factor (NGF) levels and NGF low-affinity receptor (p 7S-NGFr) distribution in the brain were analyzed. Nandrolone, subcutan eously injected in rats for several weeks, caused an increase of NGF l evels in the hippocampus and septum and a decrease in the hypothalamus ., The number of p75-NGFr-immunoreactive neurons and the p75-NGFr expr ession levels were reduced in the septum and vertical and horizontal B roca's bands. Testosterone injections caused an increase of NGF levels in the hippocampus, septum, and occipital cortex and induced an upreg ulation of p75-NGFr in the forebrain NGF target regions, This testoste rone effect suggests that nandrolone and testosterone affect brain NGF target cells by a different mechanism(s), Nandrolone may interfere wi th NGF transport and/or utilization by forebrain neurons, causing an a ltered p75-NGFr expression and NGF accumulation as a consequence. Sinc e NGF is known to maintain forebrain neurons and to regulate neurobeha vioral functions, including memory, learning, and defensive behavior, it is possible to hypothesize that this neurotrophin may play a role i n the mechanism of action of anabolic androgenic steroids (AAS) in the brain and be associated with endocrine and behavioral dysfunctions oc curring due to AAS abuse. (C) 1997 Wiley-Liss, Inc.