Gene relaxation and aging: changes in the abundance of rat ventral prostate SGP-2 (clusterin) and ornithine decarboxylase mRNAs.

Sulfated glycoprotein 2 (SGP-2) mRNA progressively increased in the ventral prostate of the aging rat, reaching, at 24 months, 4-fold higher than at 3 months. Ornithine decarboxylase (ODC) mRNA peaked at 6 months (4-fold increase), and at 12 and 24 months was maintained at higher levels than at 3 months. ODC enzymatic activity was enhanced at 6 months to a much smaller extent than its own mRNA, the values at 12 and 24 months dropping to below those at 3 months. Putrescine (Put), spermidine (Spd) and spermine (Sp) concentrations also peaked at 6 months (100% increase for Put, 50% for Sp and Spd). At 24 months, Put and Spd were diminished, and Sp was unchanged with respect to the 3-month values. Under the same conditions, glyceraldehyde-3-phosphate dehydrogenase mRNA did not undergo significant alterations.