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Testosterone 5α‐Reductase in Rat Brain
Author(s) -
Krieger Neil R.,
Scott Robert G.,
Jurman Mark E.
Publication year - 1983
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1983.tb13591.x
Subject(s) - olfactory tubercle , endocrinology , testosterone (patch) , medicine , hypothalamus , dihydrotestosterone , caudate nucleus , diencephalon , thalamus , midbrain , preoptic area , hippocampus , chemistry , enzyme , biology , striatum , androgen , olfactory bulb , biochemistry , central nervous system , dopamine , neuroscience , hormone
We describe a simple procedure for the microassay of testosterone 5α‐reductase in homogenates of rat brain. This enzyme converts testosterone to dihydrotestosterone. We have used this assay to characterize the enzymatic activity and to map its distribution. The apparent K m is 4.1 × 10 −6 M and the V max is 85.6 pmol/mg protein/h. The pH optimum is broad and extends from pH 6.0 to 8.0. For the brain regions surveyed, testosterone 5α‐reductase activity varied over a 10‐fold range. The highest activities were observed in homogenates of the midbrain and pons (37–39 pmol/mg protein/h). The lowest were seen in homogenates of the thalamus, caudate nucleus, frontal cortex, hippocampus, hypothalamus, olfactory tubercle, and preoptic area (3–7 pmol/mg protein/h).