Effects of Saline Loading on the Renin, Erythropoietin, and Blood Pressure Responses to Canine Renal Allotransplantation

Abstract

Serial determinations of plasma erythropoietin and renin activities and mean arterial blood pressure were done in five dogs before and after renal allotransplantation. Throughout the experiment, the animals were given 154 mEq of NaCl per day, starting 1 week before transplantation. No immunosuppressive therapy was given. Onset of immunological rejection was determined by daily measurement of endogenous creatinine clearance. Arterial pressure and plasma erythropoietin concentration increased markedly at the time of rejection, with the curves for the two variables closely paralleling each other in all animals. Serial determinations of plasma volume done in two of the dogs did not show any significant change at the time when hypertension appeared. Plasma renin activities remained very low throughout the experiments, indicating that even with the vascular lesions of rejection renin release is still subject to normal control mechanisms. It is concluded that elevated plasma renin activity is not an essential causal factor of the hypertension which occurs with renal allograft rejection. Since it is possible to suppress renin release without substantially inhibiting erythropoietin release, different stimuli appear to cause release of these substances. ADDITIONAL KEY WORDS renal allograft rejection renal hypertension sodium ion• In previous studies of canine renal allograft recipients, plasma activities of both erythropoietin and renin increased during immunological rejection (1). The increased hormone levels were accompanied by rises in From the

Polycythemia following renal transplantation unrelated to the allograft

“…The erythropoietin levels in this case did not show any correlation with t h e plasma renin levels, confirming the opinion of other workers who have suggested that they are stimulated independently (Abbrecht et al, 1969).…”

Renin and erythropoietin release in renal allotransplantation states

“…Thus, ESF elevations as observed in the present series of experiments (Tables I and 11) reflect essentially renal foci or stimuli. In contrast, as in man (Capelli et al, 1968), extrarenal renin sources are known to exist in the dog. Variations or the lack of them as noted in the currently reported experiments may in part also be influenced by this feature.…”