Estrogen attenuates progressive glomerular injury in hypercholesterolemic male Imai rats.

Hypercholesterolemic Imai rats spontaneously develop proteinuria and glomerulosclerosis, especially in males. A sex difference in glomerular injury has been recognized, but the role of sex hormones in glomerular injury remains unclear. Therefore, we investigated whether estrogen administration influences the progressive glomerular injury in male Imai rats. Estrogen produced a significant decrease in body weight. Systolic blood pressure in estrogen-treated rats was significantly lower than that in controls. Estrogen attenuated the progression of glomerular injury by significantly reducing proteinuria and glomerular sclerosis. The glomerulosclerosis index was significantly higher in controls than in estrogen-treated rats. Estrogen suppressed serum testosterone levels, whereas it increased GH levels. Results suggest that estrogen appears to play an inhibitory role on the development of glomerular injury, by itself or in association with sex-related factors regulated by estrogen and testosterone.