PROLACTIN AND TESTOSTERONE REGULATION OF MITOCHONDRIAL ZINC IN PROSTATE EPITHELIAL-CELLS

The prostate gland of many animals accumulates extremely high levels o f zinc and citrate. Evidence currently exists in support of a concept that zinc might be an important regulator of m-aconitase and citrate o xidation of prostate epithelial cells. No information concerning the m itochondrial levels of zinc has been available. The roles of testoster one and prolactin in the regulation of zinc have not been established. Tn this report, we determined the levels of tissue and mitochondrial zinc of rat lateral prostate (LP), ventral prostate (VP), dorsal prost ate (DP), liver, and kidney. The results demonstrate that the mitochon drial zinc levels of the prostate cells were higher than levels of non prostatic cells. The LP contained severalfold higher zinc levels than DP and VP. The effects of testosterone and prolactin in vivo and in vi tro on the zinc levels were also determined. Both hormones significant ly increased cellular and mitochondrial zinc levels of LP cells; decre ased the zinc levels of VP cells; and had no effect on the zinc levels of DP, liver, or kidney cells. These effects are direct and physiolog ical effects of the hormones on the targeted prostate epithelial cells . The hormonal effects on mitochondrial zinc of LP and VP epithelial c ells correlate perfectly with their effects on citrate oxidation. The results support the concept that mitochondrial zinc is an inhibitor of m-aconitase and citrate oxidation; and that prolactin and testosteron e regulation of mitochondrial zinc provides a mechanism for their regu lation of citrate oxidation in citrate-producing prostate epithelial c ells. (C) 1997 Wiley-Liss, Inc.