ESPE Abstracts

Background: Increased caloric intake in dietary obesity (DO) could be driven by central mechanisms regulating reward-seeking behavior. Leptin modulates the mesolimbic dopamine system and vice versa.

Objective and hypotheses: We supposed D2 dopamine receptor agonists to influence weight gain and leptin level in genetically unmodified rats (GUR) with high caloric diet (HCD) as dietary obesity.

Method: Male rats (n=48, 183.0±14.0 g) were divided into HCD group (n=24) and control (C) (n=24, standard diet). HCD rats received daily i.p. injections of bromocriptine (Br) (1 mg/kg), dimethyl sulfoxide (vehicle, 1 ml/kg), and both (n=8, respectively) during 3 months. Length, weight, and caloric intake were registered twice a week. Both leptin levels (immunoenzyme analysis with standardization relatively to length/weight coefficient (LWC) and rodents’ total mobility (TM, plus maze test) were detected at the first and third months. Nonparametric analysis was performed (SPSS 16.0, P<0.05).

Results: HCD rats showed weight gain in first and third months irrespective to injected agent (P<0.05). Weight gain was similar in Br injected HCD rats and HCD group (P>0.05). TM had no changes in HCD group after 1 month whereas open arm visits significantly decreased in HCD one (P<0.05). TM diminished after 3 months compared to C rodents and to the same group after 1 month (P>0.05). Br injected HDC rats showed TM decrease and closed arm time increase in 1 month relative to HDC group. These changes were leveled in 3 months. Leptin trended to decrease after 3 month of Br injections in HCD rats (P>0.05), but LWC reduced significantly (P=0.028) related to the HCD rodents. Leptin and LWC levels were extensively lower in Br injected HCD group at third month in regard to first month.

Conclusion: We supposed long term bromocriptine injections to prevent obesity in HCD GUR.