Genetic variation in esteroproteases in the mouse submandibular gland

Structure of mouse kallikrein gene family suggests a role in specific processing of biologically active peptides

The glandular kallikrein gene family comprises 25-30 highly homologous genes that encode specific proteases involved in the processing of biologically active peptides. In the mouse all the members of this family are closely linked on chromosome 7. The 9.5-kilobase nucleotide sequence of a mouse genomic clone contains one complete kallikrein gene (mGK-1), which is expressed in the male mouse submaxillary gland, and the 3' end of another (mGK-2). Differences in the coding potential of these genes and the amino acid sequences of other known kallikreins seem to be functionally related to the substrate specificity of the different enzymes.

Comparison of genetic and endocrine control of renin and kallikrein in mouse submandibular gland

The effects of strain, sex, hypophysectomy and hormone treatment on mouse submandibular gland renin, kallikrein, S2266 hydrolase, and BAEe esterase activities have been examined. Renin activity is determined by the Rnr locus on mouse Chromosome 1. Female SWR/J mice (Rnrs/Rnrs) have 1000-fold higher submandibular gland renin activity than C57BL/6J mice (Rnrb/Rnrb). Both strains have similar kallikrein activity. Renin, BAEe esterase, and S2266 hydrolase are substantially higher in male mice compared to females of the same strain whereas kallikrein is not. Dihydrotestosterone and/or thyroxine treatment induces renin, BAEe esterase, and S2266 hydrolase in female mice with little effect on kallikrein. All four enzyme activities are profoundly reduced by hypophysectomy. Dihydrotestosterone and thyroxine are both required to restore renin, BAEe esterase, and S2266 hydrolase to induce levels. Dihydrotestosterone and/or thyroxine restores kallikrein to control levels. We conclude that renin and kallikrein in the mouse submandibular gland are under different genetic and endocrine control. In addition, the synthetic substrate S2266 is not a specific substrate for kallikrein activity in mouse submandibular gland cytosol.