Endocrine Abstracts

Puberty, one segment of a larger developmental continuum in humans, is characterized by major transformations in body such as highest growth, sexual development and distribution of fat in different body regions. Leptin is regarded as an essential adipokine that regulates intake of food, expenditure of energy and body fat mass. It is well known that alterations in nutritional states markedly influence growth hormone (GH) secretion, which in turn regulates linear growth, muscle strength, body fat mass and lipid metabolism. Also, leptin affects bone metabolism via direct signaling from the brain. Leptin decreases cancellous bone, but increases cortical bone, which is a mechanism for increase in bone size. Leptin may also act directly on bone metabolism via a balance between energy intake and the IGF-I pathway. Therefore, this study was designed to examine possible associations between plasma concentrations of leptin and GH, linear growth velocity (LGV), body mass index (BMI) and body surface area (BSA) at different ages and developmental stages in boys between 1 to 20 years (27 boys/age group). The concentrations of leptin and GH were determined using specific ELISA, while LGV, BMI and BSA were calculated using formulae for each age/stage group. Data were analyzed using Student’s t test, ANOVA and Pearson correlation r. Our results showed a positive correlation between plasma leptin and GH levels at 3rd, 6th, 8th, 10th, 12th, 16th to 18th and 20th year of age and at infancy, early puberty and late puberty. The leptin levels and LGV were positively correlated at 3rd, 4th, 8th to 10th, 12th and 16th to 18th year of age indicating correlation at early puberty and late puberty. Moreover, the leptin levels and BMI were positively correlated at 1st, 4th to 6th, 8th, 9th, 12th, 15th and 18th to 20th year of age demonstrating correlation at infancy and early puberty. Likewise, the concentrations of leptin and BSA were positively correlated at 1st, 2nd, 5th through 12th, 19th and 20th year of age showing relationship at infancy, pre-puberty and early puberty. In conclusion, leptin and GH, LGV, BMI and BSA were found to be positively correlated at infancy and early puberty.