Abstract

Studies on female athletes with low fat mass showed that low plasma leptin level can predict menstrual disorders, but the relationship between levels of leptin and sex hormones in athletes, especially those with menstrual disorders, is unknown. This study investigated secondary regulators of plasma leptin level, such as prolactin, testosterone, sex hormone-binding globulin (SHBG) and nutritional status, in female athletes. Thirty-two female professional swimmers with oligomenorrhoea, aged 18±2 years, with a training period of 5.3±2.7 years and body mass index (BMI) of 21.1±2.1 kg/m², divided in two groups with too high (IL) or too low plasma leptin level (DL) participated in the study. The nutritional status was evaluated basing on analysis of the body composition using Bioelectrical Impedance Analysis method (percentage of adipose tissue (FM) and lean body mass (FFM)) and skinfold thickness using Harpenden skinfold caliper. Serum levels of leptin, prolactin, testosterone and SHBG were measured. IL athletes were younger (IL: 17±1 years, DL: 19±2 years; p<0.05) than DL athletes. BMI, ST and FM were higher (p<0.05) in IL athletes but FFM was lower (p<0.05) compared to DL swimmers (BMI: IL 22.4±2.3 kg/m², DL 20.3±1.5 kg/m², ST: IL 12.6±4.0 mm, DL 9.6±2.1 mm, FM: IL: 23.2±5.0%, DL: 19.2±3.5%, FFM; IL 76.8±5.0%, DL 80.8±3.5%). Furthermore, the results of plasma leptin level correlated (p<0.05) with anthropometric parameters (age: r=−0.39, body mass: r=0.47, BMI: r=0.52, ST: r=0.38), body composition (FM%: r=0.45, FFM kg: r=−0.45), prolactin (r=0.67) and testosterone level (r=0.45). The results confirm the strong influence of body mass and fat mass on serum leptin levels. Moreover, high prolactin and testosterone levels may also favourably increase plasma leptin level in athletes and affect menstrual disorders.