Renal transplantation between male and female spontaneously hypertensive rats.

The higher blood pressures of male compared with female spontaneously hypertensive rats (SHR) are the result of the inheritance of different sex chromosomes, although the pathophysiology has not been defined clearly. The reported hypertensive effect of kidneys transplanted from male SHR raises the possibility of a sex-specific renal abnormality, but the effects of transplanting female SHR kidneys have not been studied. To test this hypothesis, single kidneys were transplanted from male SHR into female SHR recipients and vice versa, followed by removal of the native kidneys of the recipients. Male and female SHR that had undergone uninephrectomy were used as controls. After surgery at 14 weeks of age, systolic blood pressures were measured each week until 30 weeks of age. The replacement of a SHR female kidney with a SHR male kidney was not associated with any significant rise in blood pressure, and the replacement of a SHR male kidney with a kidney from a female SHR was not associated with any reduction in blood pressure. These results indicate that the sexual dimorphism of SHR blood pressure is not the result of intrinsic renal differences between males and females and that nonrenal factors would be more likely to explain the blood pressure differences between the sexes.