Modification of renin isoelectric heterogeneity in Goldblatt hypertensive rat

Abstract

Six forms of renin have been described in rat kidney. Different stimuli resulted in secretion of unique profiles of those forms. We studied their storage and secretion in the two-kidney, one-clip Goldblatt hypertensive rat (GHR). Renal venous blood, kidney homogenates, and incubation media from cortical slices were subjected to isoelectric focusing. In all samples tested, six peaks of renin activity were found with isoelectric points at pH 5.90, 5.70, 5.40, 5.20, 5.00, and 4.80. The quantity of renin activity for each form was expressed as a percentage of the total recovered from the gel. In control kidneys the profile of renin stored and that released by in vitro slices were similar. However, in plasma, the percentage of renin focusing at the more basic pH was decreased. This is in agreement with other work showing that the liver removes the more basic forms more rapidly than the acidic forms. The clipped kidney of GHR secreted, both in vivo and in vitro, a profile of renin forms that was significantly different from the control kidney. The difference was expressed by an increase in the secretion of the more acidic forms by the clipped kidney. It is hypothesized that changes in the secretory profile of renin may reflect changes in storage and synthesis of those forms.