CALORIC RESTRICTION DIMINISHES THE AGE-ASSOCIATED LOSS OF IMMUNOREACTIVE CATALASE IN RAT PROSTATE

BACKGROUND. Caloric restriction (CR) retards aging and diseases in mic e, rats, and other animals by unknown mechanisms. A popular hypothesis is that CR acts by opposing age-associated increases in oxidative str ess. METHODS. Because influences of CR on antioxidant enzymes in the p rostate have not been previously investigated, immunohistologic method s (light and electron microscopy) were used to determine the prostatic localization of catalase (CAT) in rats of diverse ages (3-32 months) fed either normally or subjected to CR from age 16 months. RESULTS. In 20-month-old rats fed either diet, CAT appeared as dense deposits at the apical poles of the epithelium in the lateral lobes, and within th e ductular lumens, suggesting that CAT is secreted. Confirmation of bo th liver peroxisomal and prostatic apical cytoplasmic localization of CAT was provided by electron microscopic immunogold staining. The amou nt of CAT was reduced at 30 months in normally fed rats but not in tho se on CR. CONCLUSIONS. CAT appears to be a secretory product of the ep ithelial cells in the lateral lobes of the rat prostate. Further, CR f rom late-middle age opposed the age-associated loss of this intracellu lar enzyme activity. (C) 1997 Wiley-Liss, Inc.