Testosterone metabolism by the prostate of the aging AXC rat

Testosterone metabolism by the ventral prostate of inbred, senescent (36-month-old) AXC rats showed a shift to increased oxidative and diminished reductive metabolism when compared to young mature (3-month-old) or mature adult (6-month-old) AXC rats. The change was principally attributable to diminished production of 5 alpha-dihydrotestosterone and increased production of 4-androstenedione. By contrast, dorsolateral prostate testosterone metabolism in these same rats was always more reductive than that of ventral prostate and failed to show the post-maturation shift to oxidative testosterone metabolism which characterized ventral prostate. Co-incubation of either ventral or dorsolateral prostate from any of these rats with testosterone and estradiol showed that estradiol did not significantly affect prostate testosterone metabolism. Plasma testosterone content of senescent AXC rats was only 28% of that of mature adult rats. Chronic exogenous testosterone treatment enhanced reductive testosterone metabolism by ventral prostate and eliminated those changes in metabolite distribution which had differentiated testosterone metabolism by young and senescent AXC rats. The data support the interpretation that the aging-related diminution in AXC rat ventral prostate reductive metabolic capacity is primarily the consequence of diminished 5 alpha-dihydrotestosterone production secondary to diminished plasma testosterone content.