RESUMO
PIP: The electrophoretic mobility of renin substrate in human plasma was determined by electrophoresis of the plasma on a cylinder of polyacrylamide gel, followed by slicing the gel, incubation of each slice with human renin, EDTA, and BAL in saline, and determination of the angiotensin formed by radioimmunoassay. With this modified technique 5, and possibly 8, electrophoretically dissimilar renin substrates have been found in human plasma. Significant variations in the patterns of renin substrates in the blood plasma of pregnant women and of those taking oral contraceptives were shown. In normal plasma from male or female subjects there was a single large peak of renin substrate with a mobility slightly less than that of albumin, and there were a series of very small peaks of renin substrate with lesser mobilities than the major peak. Increasing the sample size and prolonging the period of incubation with renin made the smaller peaks more apparent. In women using oral contraceptives, a distinctly different pattern of renin substrates was found. Early smaller peaks were increased. The major peak was sometimes increased also. Pregnancy produced a strikingly different pattern of renin substrates. There was an increase in all slow-moving peaks and their bases ran together without a return to the baseline. The absence of peaks when renin was omitted indicated that they were renin substrates. In 2 of 4 patients having cirrhosis of the liver with ascites, the amount of major substrate peak was greatly diminished and minor peaks were somewhat reduced. In 3 bilaterally nephrectomized patients, the major peak was not increased and the pattern of minor peaks was normal.^ieng
