Endocrine Abstracts

Objective: In order to determine the plasmatic levels of leptin in adult Wistar rats (90 days +7 days) which had undergone specific types of stress, a prospective study was done in which the stimulus was presented in the proestrus stage and the samples, recovered by decapitation 24 h after the initial stimulus, were centrifuged and stored for analysis of leptin by radioimmunoassay (RIA).

Methods: The rats were divided into four groups: Group I (n=14) the control group, Group II (n=16) underwent laparotomy, being anesthetized with 2.2 tribromoethanol 2.5% 1 mg/100 ml weight, Group III (n=15) suffered stress caused by lack of light for 24 h and Group IV (n=15) were given 24-hour lighting stimulus (cold light, 20 W).

Results: There was no variation in weight for any of the groups. In Group I, leptin levels varied from 0.476 to 6.714 ng/ml, with a median of 2.667 ng/ml; in Group II, from 0.384 to 1.448 ng/ml, with a median of 0.895 ng/ml; in Group III, from 0.484 to 2.346 ng/ml, with a median of 1.856 ng/ml; in Group lV, from 1.003 to 3.181 ng/ml, with a median of 2.024 ng/ml.

Conclusion: It was concluded that the plasmatic levels of leptin suffered significant reductions in adult Wistar rats suffering from stress produced by surgery, when compared with other groups.