Acta Physiologica 50. (1977)
1. szám - PHYSIOLOGIA - Hahn Z.-Lénárd L.: Sex-dependent consequences of bilateral pallidal lesion after postpuberal castration in rats
20 Z. HAHN, L. LÉNÂRD 1967; Valenstein et al. 1969; Wade and Zecker 1970; Redick et al. 1972; Roberts et al. 1972; Jankowiak and Stern 1974; Stern et al. 1974) have drawn attention to the possible role of peripheral testicular or ovarian hormone levels in the changes caused by bilateral pallidal lesion. Castration prior to the lesion was performed in order to decide if sexual steroids had a part in the weight changes or their sex-dependence after lesion. Food and water deprivation of intact males and females served to elucidate whether differences in the body composition of the two sexes had an influence on weight loss. Long-term observation of body weight of the survivors served to elucidate whether the lesion had any effect on the weight of castrated and noncastrated animals in the post-aphagic phase of the experiment. Prolonged observation of weight could be done only in females as the majority of lesioned males died. Vaginal smears of non-castrated female survivors were studied in order to screen their sexual steroid regulation. Methods A total of 125 CFY rats, 60 males and 65 females ofpostpuberalage(85—95 days), were used in the experiments. Mean body weight of males was 452 g and that of females 305 g. The animals were caged individually after being transferred to the laboratory 10 days before surgery. Food and water were available ad libitum. The operation was carried out under sodium pentobarbital anaesthesia (40 mg/kg). The lesioning electrode was a stainless steel wire insulated with a glass tube in all its length except for 0.5 mm at the tip. Lesion was induced by passing 2 mA anodal DC for 15 sec. Stereotaxic coordinates were: A: 6.6 m, L: 3.0, V: 0.0, chosen according to the data of DeGroot (1959). Bilateral lesions were made in every case. When the lesion was combined with castration, the animals were castrated three weeks before lesioning. Body weight and food and water consumption were recorded daily to the nearest g or ml, for 14 days after lesion. Body weight was measured in all lesioned groups on the day of castration and surviving females were weighed on the 90th day after lesion. The method of artificial food and water administration, amounts and composition of the diet were the same as described previously (Lénárd et al. 1975). A 30-day survival was considered long-term in the present experiments. Five ml of Ringer’s solution were administered daily to animals in a series of experiments designed to demonstrate sex-dependence of body weight loss on food and water deprivation of intact animals in order to postpone death and thus to allow development of sexdependent changes on the 5th—10th day of deprivation. Vaginal smears were collected daily with a stainless steel loop in the 75—87-day period after lesion and evaluated after methylene blue staining. Animals were sacrificed by decapitation after completion of the experiments and lesions were localized histologically (Gallyas 1969). The i-test and Fisher’s exact probability test were used for statistical evaluation of means and group comparisons, respectively. Results A period of practically complete aphagia and adipsia followed the lesion in non-castrated males and females in the first 5 postoperative days (Fig. la). Spontaneous food and water intake was resumed sooner and more often in the female than in the male group. Acta Physiologica Academiae Scientiarum Hungaricae 50, 1977