The morphology and antihypertensive effect of renomedullary interstitial cells derived from Dahl sensitive and resistant rats.

The renomedullary interstitial cell (RIC) has been implicated in the antihypertensive action of the kidney. This cell has been isolated in tissue culture and shown to have an antihypertensive action in several models of experimental hypertension. Morphometric studies of RIC in vivo from Dahl rats sensitive and resistant to the hypertensive effects of high-salt diets indicate major differences between the RICs. These cells were therefore isolated from salt-sensitive and salt-resistant strains of rat, grown, and maintained in tissue culture. Major morphologic differences between the two cell lines were noted and persisted for multiple tissue culture passages. The cells from resistant animals were larger and had more lipid granules. These differences were similar to those seen in vivo. In short-term experiments these cells were compared for their antihypertensive effect. The two cell lines were injected subcutaneously into two groups of hypertensive recipient rats, one group of Dahl salt-sensitive rats on a high-salt diet and one group of Wistar rats subjected to the one-kidney, one-clip Goldblatt procedure. In both cases differences were noted between the cell lines. These data support the concept that differences between the Dahl salt-sensitive and salt-resistant rats may be related to variations in their RIC.