The effects of hog pancreatic kallikrein on the plasma kinins-prostaglandins and renin-angiotensin-aldosterone systems

Abstract

Recently several reports have been presented stating that glandular kallikrein is present in human and animal blood, and that the oral administration of hog pancreatic kallikrein (HPK) normalises decreased urinary kallikrein and prostaglandin E2 (PGE2) excretions and elevated blood pressure in hypertensive patients. In this study, HPK (2,000 KU/kg body weight) was intramuscularly injected into male rabbits, and several hormones (plasma kinins, plasma PGE, plasma 6-keto PGF1 alpha, plasma thromboxane B2 (TXB2), plasma renin activity (PRA), plasma aldosterone, plasma ACTH) were measured before and after HPK administration in order to clarify the role of glandular kallikrein in the blood. Plasma kinins concentrations were significantly increased (the mean baseline level: 1 +/- 1 pg/ml (mean +/- S.E.), 30 min: 230 +/- 22 (p less than 0.001), 60 min: 288 +/- 36 (p less than 0.001), and 120 min: 130 +/- 9 (p less than 0.001] after HPK administration. Plasma levels of PGE were slightly increased after HPK administration, but the change was not significant as compared with the mean baseline level. Plasma levels of 6-keto PGF1 alpha were significantly increased from the mean baseline level of 229 +/- 38 pg/ml to 594 +/- 131 (p less than 0.05) at 30 min and to 378 +/- 67 (p less than 0.01) at 60 min but were decreased to 278 +/- 37 at 120 min after HPK administration. On the other hand, the changes in plasma TXB2, aldosterone and ACTH concentrations, and PRA were not significant before and after HPK administration. From the present study, it was clarified that the exogenous intramuscular administration of HPK increased plasma levels of kinins and PGI2, but induced no elevation in plasma levels of other hormones including PRA. Therefore, it was concluded in this acute experiment that there was a close relationship between the kallikrein-kinin system and PGs.