Does renotropin have a role in the pathogenesis of hypertension?

The existence of an organ-specific, circulating renal growth factor, renotropin, has been established through various bioassays. However, renotropin may be more than a growth factor. The pathogenesis of essential hypertension is unknown, although a humoral agent related to renal metabolism is believed to be responsible, at least in part. In parallel with the development of a renotropin assay, we have measured vasomotor and natriuretic serum activities. Our data suggest that renotropin possesses vasomotor and natriuretic properties. Through one or both properties, renotropin may play an important role in essential hypertension. This possibility is strengthened by observations that: a) many methods to produce experimental hypertension involve elevations of renotropin--a reduction of renal mass and/or prevention of compensatory growth; b) high renotropin activity has been demonstrated in genetically hypertensive rats (SHR); and c) sera containing high renotropic activity stimulate contraction of isolated rat aortic rings and influence organic anion and cation transport.