ABSTRACT
Objective To investigate the effects of diets with different calorie and nutritional values on pubertal onset in female rats. Method Female Wistar rat models receiving calorie-deprived (group R) (Experiment 1) ,fat-rich(group F) ,glucose-rich(group G) and protein-rich(group P) (Experiment 2) test diets were established,and rats receiving diets with normal caloric value were considered as control group (group C). The body weight (BW) ,food-intake and vaginal patency (VP) were observed. The rats were killed at the day of vaginal patency. The BW, uterus weight (UW), uterus index (UI), calorie intake per day (CI), perirenal fat weight (PFW) and perirenal fat index (PFI) were measured. The serum levels of leptin, ghrelin, IGF- Ⅰ were tested by means of ELISA.Results Experiment 1:The VP was retarded in group R compared with group C (P<0. 01). There was a significant difference in BW, UW,UI ,CI,leptin and ghrelin at the VP day between group R and group C (all P<0.01) ,and no significant difference in IGF- Ⅰ levels between these two groups. Experiment 2 :The VP was retarded in group F,group G and group P in comparison with group C (P<0.01). The BW, PFW and PFI in group G and group F were markedly higher than those in group P and group C. The leptin level in group F was the highest, and the lowest in group P. The ghrelin level in group G was the highest,and that in group P was the lowest. However,there were no significant differences in IGF- Ⅰ and UI among these, four groups. Conclusion The normal pubertal onset of female rats requires sufficient caloric stores and balanced nutrient. Diets malnutrition and fat-rich, glucoserich and protein-rich test diets all delay pubertal onset in female rats.