Peptides in Urine of DCA-Treated and Figure-of-8 Rats.

Summary A peptide material has been extracted from rat urine which decreases blood pressure of normal rats, raises blood pressure of rats with sympathetic system blocked, and causes contraction of uterine muscle. The activity of the extract is greatly increased in rats treated several weeks with DCA, but there is no clear relationship between the increase in the active substance and the onset of the hypertension. In renal hypertension pressor activity of the urine extract was not increased, even after hypertension had developed. It is highly probable that 2 or more peptides are involved. Anephrotensin, bradykinin and or kallidin may be the active agents, or the activity may be due to some as yet undescribed substance or substances. The possibility that angiotensin or vasopressin is the active component has been ruled out.