| Abstract: | In mature outbred Swiss male mice, submandibular gland renin enzyme activity is 4- and 10-fold higher than in glands of prepubescent males and mature females, respectively. Levels of translatable renin mRNA have been studied in mouse submandibular gland during postnatal development and following administration of testosterone. The [35S]methionine-labeled cell-free translation products directed by male glandular mRNA contain a 47 +/- 2kd renin precursor that is not detected in products coded by prepubescent male or female gland mRNA. This cell-free synthesized precursor is detected immunochemically only in the translation products of gland mRNA from males of 33 days or older and from females receiving testosterone administration, a pattern consistent with the measurements of renin enzyme activity. This increase in biologically active renin mRNA is a selective one, since unfractionated male and female mRNAs have similar overall nucleotide sequence complexity corresponding to 1% of mouse single copy DNA. The cDNA transcribed from male gland mRNA reacts 5- and 10-fold faster with the template mRNA than with female or prepubescent male gland mRNA, respectively, which indicates that the male gland contains abundant nucleotide sequences that exist at low concentration in the female or prepubescent male. Selective hybrid arrested translation confirms that the levels of renin mRNA are lower in the glands of prepubescent males than in those of the mature males. These data indicate that the regulation of renin enzymatic activity by androgens is mediated by an increase in the levels of translatable renin mRNA both during postnatal development and after testosterone administration. |
