The Relationship between Nocturnal Urinary Leptin and Gonadotrophins as Children Progress towards Puberty

Abstract

Background/Aims: Leptin is necessary for normal human pubertal development but its exact role in the period leading up to the onset of puberty has not been defined. This study has assessed the relationship between leptin and gonadotrophin secretion over time as children progress into puberty. Subjects and Methods: Twenty children (13 boys and 7 girls) judged to be close to the initiation of puberty were recruited. Three consecutive first morning urine samples were collected from each subject each month over 6 months. At the end of the study, the children were classified into those who remained physically prepubertal (n = 7) and those that had advanced in puberty (n = 13). Leptin and gonadotrophins were measured by immunoradiometric and immunofluorometric assay, respectively. Results: Total urinary leptin excreted over 6 months was higher in girls than in boys, both prepubertally and in early puberty, and in both sexes, was higher in those advancing into puberty than in those remaining prepubertal (girls 8.0 vs. 3.4 ng/l and boys 3.6 vs. 1.7 ng/l; both p < 0.05). In the whole group, when controlling for gender, there was a significant correlation between both leptin and luteinizing hormone (LH; r = 0.43, p < 0.001) and leptin and follicle-stimulating hormone (FSH; r = 0.32, p = 0.001). The possibility of a lead relationship was explored by pairing leptin values with the gonadotrophin values in the following month. Leptin was significantly correlated with FSH but not LH in both pre- and peripubertal children (prepubertal r = 0.45, p = 0.01; peripubertal r = 0.32, p = 0.01). Conclusions: This study has shown that in children approaching and progressing into puberty, leptin is associated with LH and FSH over the same time frame, and with FSH when leptin is acting as the lead hormone. These data imply that leptin is an important facilitator of the early phases of human puberty.

The relationship between leptin, gonadotropic hormones, and body composition during puberty in a Dutch children cohort

“…In girls, we observed that prepubertal leptin concentrations (Tanner stage 1), when acting as a lead, related to early pubertal LH and FSH concentrations (Tanner stage 2), as observed in both boys and girls by Masqood et al (11). These results imply a temporal relationship between leptin and gonadotropic hormones during early puberty.…”

“…Relationships between dependent and independent variables were determined using simple linear regression models. To investigate a timedependent relationship in the sequence of the hormonal changes during puberty, we used the lead/lag technique, which correlates hormones secreted in one stage, with those secreted in the next stage (11). All tests were two-sided and differences were considered significant at P!0.05.…”

“…To investigate a time-dependent relationship in the sequence of the hormonal changes during puberty, we used the lead/lag technique, which correlates hormones secreted in one stage, with those secreted in the next stage (11). In girls, we observed that prepubertal leptin concentrations (Tanner stage 1), when acting as a lead, related to early pubertal LH and FSH concentrations (Tanner stage 2), as observed in both boys and girls by Masqood et al (11).…”

“…Leptin has been proposed as a physiological link between adiposity status and the start of sexual maturation (1)(2)(3)(4)(5). Several cross-sectional studies and three small longitudinal studies support this theory since they have found that leptin concentrations rose prepubertally, but then decreased at the initiation of puberty, as gonadal hormone concentrations began to increase (1,4,(6)(7)(8)(9)(10)(11).…”

“…Most studies, however, which investigated the role of leptin as a trigger to puberty, did not determine body composition (6), or were done in transversal cohorts (1,6,8,9) and relatively small longitudinal cohorts (4,10,11). Consequently, previous studies have been unable to test the hypothesis that leptin and gonadotropic hormones are temporarily related during puberty, and whether consequently the relationship between leptin and body composition is temporarily altered.…”