Restoration of sexual function and fertility by fetal hypothalamic transplant in impotent aged male rats

The purpose of this study was to observe whether fetal hypothalamic transplant can restore the neuroendocrine and reproductive function in impotent aged male rats. Eighteen to 20 month old impotent male rats received an anterior hypothalamus removed from a 17-19 day old fetus and placed into the anterior third ventricle. Controls were either without surgery (UC) or grafted with cerebral cortex (CG). Before and 2 to 3 months after transplantation, blood samples were collected from the aged rats for testosterone and LH measurement. Before and one to two months after transplantation, each hypothalamic grafted animal (HG) or control rat was put overnight into a cage which contained four, 10 to 12 week old proestrous female rats. Vaginal smear of each female was monitored early the next morning. Sperm seen in the vaginal smear was regarded as copulation and ejaculation. The test was repeated twice, one week apart, and the higher score represented the sexual function and fertility of the males. Seven of 10 HG males restored their sexual function, impregnated 9 females and fathered 106 pups. None of 7 UC restored their reproductive function and only one of 4 CG males impregnated one female which delivered 6 pups. Serum testosterone, LH and pituitary LH in the HG rats, which showed restoration of reproductive function, were significantly higher than those of the controls (UC and CG). These results indicate that the fetal hypothalamic grafts can survive and develop in the brain of impotent aged male rats and restore neuroendorince and reproductive function in senescent rats.