[Low molecule and middle molecule metabolites with haemodynamic activity in the ultrafiltrate from uraemic patients...

Substances causing blood pressure changes and myocardial damage in rats were first detected in the ultrafiltrate obtained from patients on long-term haemodialysis by means of size separation, high-voltage electrophoresis and thin-layer chromatography. Of the 100 to 140 fractions produced by Sephadex G 15 chromatography at least 3 raised the blood pressure when administered in doses of 2 to 10 mg/0.1 to 0.2 ml 0.9% NaCl, that is the high molecular fraction 18 to 23 and the low molecular fractions 71 to 72 and 73 to 74. The fractions 96 to 98 and 97 to 106 showed high toxicity. Less than 1 mg/0.1 to 0.2 ccm 0.9% NaCl produced cardiac arrest. The fractions 35 to 55, which originate from the middle molecules and are retained in regularly uraemia, contain substances which caused a reduction in blood pressure at low dosage and cardiotoxic effects at a dosage of more than 10 mg. Thin-layer chromatography indicates that the substances most probably consist of peptides whose structure contains the amino acids leucine, isoleucine, valine, glutamic acid, aspartic acid, alanine and cystine.