Renin-like (angiotensinogenase) activity in sweat of patients with cystic fibrosis and controls.

Using bioassay method (rat blood pressure technique) as well as the radioimmunoassay, renin-like activity (RLA) was measured in eccrine sweat of patients with cystic fibrosis of the pancreas (CF) and of controls. Sweat-formation was induced by pilocarpine-iontophoresis or by local injection of carbamylcholine (Doryl). RLA-values between O (not measurable) and 460 ng/ml.h were measured. With increasing sweat flow-rate a tendency to lower RLA-values was detected. No significant difference was observed between CF and controls. From the observation that RLA of sweat is up to 30 times higher than that of plasma, it is concluded that RLA is probably released not from plasma but from the sweat glands themselves, where it is stored or synthesized.