Endocrine Abstracts

Reproductive systems of the Mongolian gerbils are controlled by the photoperiod but body weight is independent of photoperiod. Food intake has an effect on reproduction and gerbils are very sensitive about food intake. Leptin hormone has controls on both food intake and body weight. Finding a link between changes in feeding behavior and reproductive activity in relation to obesity-related issues will play an important role. In this study, three groups were established; a) food was introduced as ad libitum, b) food was introduced only in dark period, c) food was introduced only in light period. Daily food consumption and weekly body weights were calculated. Estrus cycles have been observed by means of vaginal smears every day and preparations were photographed. Leptin measurement at each phase of the estrus cycle phases was evaluated separately. When all groups were compared in terms of food consumption, the control group was higher (~6.34 g/day) than in other groups however, other groups were found to be similar (~4.53 g/day). It was found that the weight variations of the three groups were similar. The leptin value in diestrus phase of both food restricted groups was higher (~24 ng/ml; P<0.05) than the control. The values in proestrus stage were similar (P>0.05), but the values in estrus stage had higher leptin when the animals were fed in the dark phase (~32 ng/ml; P<0.05). Leptin in metaestrus stage was lower in the group fed in the light phase but other groups had similar leptin values (~7 ng/ml; P<0.05). 4-day estrus cycles of the control group were prolonged in food-restricted groups (~7–8 days). As a result, feeding behavior has led to changes both in leptin values and in the estrus cycle. Since the relationship between nutrition and leptin in recent years is important in terms of obesity, changes in feeding rhythm may directly affect on the organism’s reproductive system.