EXPRESSION OF MESSENGER-RNAS OF PANCREATIC AND L-TYPE RNASE INHIBITORS AS A FUNCTION OF AGE IN DIFFERENT TISSUES OF SAMP8 AND BDF1 MICE

Turnover of mRNAs could be influenced not only by the synthesis of dif ferent mRNA species but also by the altered levels of mRNA-degrading e nzymes such as RNases and their endogenous inhibitors. In the present work we evaluated possible age-related changes in the mRNA levels of p ancreatic as well as L type RNase inhibitors in five different tissues of the BDF1, SAMR1 and SAMP8 using Northern blots. The mRNA levels va ried depending on the tissues and mouse strains studied. In certain in stances such as the RNase L inhibitor mRNA levels in the lung of SAMP8 , there was a statistically significant (P < 0.05) increase of 40% if we compared the young (3 months old) and old (18 months old) animals. These changes could possibly contribute to a certain extent to the alr eady lower levels of mRNAs due to decreased transcriptional activities in aged animals. (C) 1997 Elsevier Science Ireland Ltd.