Renins in mouse submaxillary gland: multiple molecular forms and their renin activity in 1 - to 8-week-old mice

Renin activity in the extract from the submaxillary gland of 1-to 8-week-old albino male mice was found to increase notably with increase of age and to reach a maximum in 6-week-old mice in which the activity was 7.5 >< 105 times as high as that of 1-week-old mice. We found three unfamiliar renins of different molecular weights (Mr=48,000, M,=37,000 and M,=3l,000) in addition to a normal renin (M,= 41,000) in the submaxillary gland of 1-to 3-week-old mice. An unfamiliar renin (Mr: 31,000) increased notably in the submaxillary gland of 6-week-old mice, but it almost disappeared in the gland of 7-week-old mice in which a normal renin (M,-= 41,000) increased and became a major form of renin. The renin activity in all three of the unfamiliar renins was completely inhibited by antibodies raised against pure normal renin, suggesting that all the unfamiliar renins found in this study have a precursor common to normal renin. KEY WORDS renin / mouse submaxillary gland renin / multiple molecular weight forms of renin / age-related differences in renins