| Research Abstract |
1.The aggravating effect of ovariectomy was observed at 6 months of age of hypercholesterolemic female Imai rats, but this effect disappeared at 12 months. These results suggested that sex-hormones regulated by the ovaries may play an inhibitory role in the development of glomerular injury before 6 months of age, but not thereafter, in this model (Nephron 1996,72 : 72). However, in unilateraIIy nephrectomized SD female rats, ovariectomy resulted in attenuation of glomerular injury associated with areduction of GH,suggesting a close relationship between a reduction of GH and attenuation of glomelular injury (Nephron 1996, 73 : 251).
2.An investigation of sex-related difference and the effect of castration was performed in adriamycin-induced nephropathy (AD) of SD rats. Male rats was more susceptible than females to the development of glomerular injury in this experimental model, and castration or estrogen administration in males attenuated glomerular injury similar to SHC rats (Nephrolog
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y l996,2 : 45 and Am J Nephrol 1996, l6 : 540).
3.To clarify whether the ovaries have a potential to attenuate aggravating effect of testosterone on glomerular injury, we investigaled the effect of testosterone in females with or without ovaries, using AD female rats. The ovaries attenuated aggravating effect of testosterone and the protective effect of the ovariesmay be related to their attenuating effect on glomerular growth (Kidney and BP Res 1997,20 : 44).
4.We have already reported an equally attenuating effect of castration or estrogen administration on glomerular injury in a short-term experimental period ended 24 weeks of age (Nephrology l996,2 : 45). In this study, to clarify the importance of experimental period in studying the pathogenesis of the development of glomerular injury, we investigated a lon-term effect of castration or estrogen administration of glomerular injury using an uninephrectomized SD rats model ended 54 weeks. Castration attenuated glomerular injury, whereas estrogen failed to attenuate it, associated with an increase in plasma GH levels (Nephron l997,77 : 445). Further, we investigaled whether testosterone administration eliminates attenuating effect of estrogen of glomerular injury in estrogen-treated male Imai rats. Combined administration of testosterone and estrogen attenuated glomerular injury more than estrogen only. Testosterone in this experiment appears to act to attenuate glomerular injury associated with a reduction of CH levels (Kidney and BP Res 1997,20 : 51).
5.Attenuating effect of castration on glomerular injury is a age-dependent in unilaterally nephrectomized male SD rats, showing castrtion at 6 weeks or 3 months attenuated glomerular injury, while castration at 6 months produced no attenuateing effect (Nephron 1997,75 : 342). Less
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