Background and aim: The aim of the study was to explore the influence of heroin addiction and one year methadone maintenance treatment respectively on serum leptin levels. Methods and results: 14 heroin addicted subjects (9 men and 5 women) with average age 27.1 years (variation 22 - 38 years) and 17 control healthy subjects were included into the study. Mean duration of heroin addiction was 9 years The subjects were treated for one year with mean daily dose of 90 mg of methadone. Serum leptin levels were measured by enzymoimmunoassay, the rest of the biochemical parameters was measured by standard laboratory methods. Body Mass Index (BMI) was calculated by conventional method (kg/m2). Statistical analysis was performed using t test and paired t test. Serum leptin levels in heroin addicts (7.08 ± 2.80 ng/ml) did not significantly differ from those of control group (6.10 ± 1.23 ng/ml). One year of methadone maintenance treatment significantly increased serum leptin levels to 12.10 ± 3.17 ng/ml vs control group (< 0.05). The same was true for BMI which increased significantly from basal 21.47 ± 2.54 to 24.61 ± 2.82 (< 0.05). Conclusions: Long term addiction to heroin did not change serum leptin levels as compared with control group. One year of methadone maintenance treatment significantly increased serum leptin levels as well as BMI values. We suggest that the increase in serum leptin levels could be explained by the restoration of hypopituitary-hypothalamo-adrenal and/or hypopituitary-hypothalamo-gonadal axis by methadone maintenance treatment. Alternatively, the improvement of nutritional status with subsequent decrease in the infectious complications may be involved.

        Key words: Heroin - Leptin - Hypopiuitary-hypothalamo-adrenal axis - Hypopituitary-hypothalamo- gonadal axis - Nutrition - Methadone