No abstract

Summary: A complete description of a component-binding radioimmunoassay of rat urinary kaliikrein is presented. Each step of the radioimmunoassay was evaluated and optimized. The problems encountered in the development of the assay are discussed; this may be a guide to the treatment of similar problems in the development of a comparable component-binding radioimmunoassay. Protocols are presented for performance of the assay with [3 H]-labelled or [ 125 Ill-labelled rat urinary kaliikrein. Radioimmunoassay and immunodoublediffusion data suggested that rat plasma indeed contains an antigen similar to glandular kallikrein. However, quantitation of the antigen by the direct radioimmunoassay must await appropriate developments for efficient dissociation and/or denaturation of interfering substances. Radioimmunassay für Kallikrein in Rattenharn und Identifizierung des homologen Enzyms im PlasmaZusammenfassung: Ein komponentenbindender Radioimmunassay für Kallikrein in Rattenharn wird vollständig und ausfuhrlich beschrieben. Jeder Schritt des Radioimmunassay wurde ausgewertet und optimiert. Die bei der Entwicklung der Bestimmung aufgetretenen Probleme werden diskutiert; dies kann eine Anleitung für die Behandlung ähn-licher Problerne bei der Entwicklung eines vergleichbaren komponentenbindenden Radioimmunassay sein. Protokolle für die Durchführung der Bestimmung mit 3 H-bzw.

Urinary and renal rK1-kallikrein was studied in spontaneously hypertensive rats (SHR) and their normotensive controls (WKY). It was demonstrated that the antiserum used for kallikrein radioimmunoassay (RIA) reacts with rK1- but not with rK7-protein. The specificity of the kininogenase assay was tested: rK7 had only 8% of the activity of rK1. Urinary kallikrein excretion by RIA was reduced by about two thirds in 5-week-old SHR compared WKY (11.5 versus 37.1µg/24h). On the contrary, the kidney content of rK1-kallikrein by RIA was increased by 40% in these rats (11.6 versus 8.4 ng/mg protein). The increase in kidney rK1 was confirmed by kininogenase assays. The same pattern of reduced urinary and increased renal rK1-kallikrein was observed in 8-week-old SHR rats. Kidney rK1-kallikrein mRNA tended to be lower (0.10 > p > 0.05) in SHR compared to WKY rats, suggesting that the increased kidney rK1 content is not due to increased rK1 synthesis. We hypothesize that the combination of high kidney content and low urinary excretion may be due to a defective mechanism for secretion of rK1 into the urine by tubular epithelial cells.