Tissue-specific control of glandular kallikreins

Abstract

Glandular kallikreins are kinin-generating serine proteases found in the salivary glands, pancreas, reproductive organs, and kidney and in their secretions. They are physico-chemically, enzymatically, and immunologically identical but it is not known whether they perform similar functions at these separate anatomical sites. A specific radioimmunoassay was used to measure immunoreactive kallikrein in these tissues of the rat after various stimuli. Salt depletion significantly increased kallikrein in the kidney from 2.35 +/- 0.17 to 4.11 +/- 0.27 microgram/g tissue (P less than 0.01, 16 DF) and in the salivary glands from 16.8 +/- 2.1 to 24.2 +/- 0.9 mg/g tissue (P less than 0.01, 16 DF), but did not change pancreatic kallikrein. Deoxycorticosterone (2.4 mg s.c. over 8 days) led to a doubling in kidney kallikrein, from 2.35 +/- 0.17 to 5.27 +/- 0.56 microgram/g tissue (P less than 0.01, 18 DF), without changing salivary gland or pancreatic kallikrein, whereas testosterone (240 micrograms/day s.c. over 15 days) significantly increased salivary gland kallikrein from 26.6 +/- 2.1 to 42.2 +/- 1.8 mg/g tissue (P less than 0.01, 18 DF) with no increase in kidney or pancreatic kallikrein. Accordingly, the glandular kallikreins in these tissues vary independently, which suggests they are under different electrolyte and endocrine control and may perform different physiological functions at each anatomical site.