Background: Relationship between plasma leptin and adiposity and gender has been reported in adults. Effects of age on plasma leptin is unclear and regulation of leptin production by white adipose tissue is still poorly understood.
Objectives: To study if age and parameters of lipolysis are related to plasma leptin concentrations.
Methods: Seventy-seven healthy, normal-weight subjects (age range 19-82 y.) had measurements of body composition (18oxygen dilution technique) and of fasting plasma levels of leptin, glycerol, and nonesterified fatty acids (NEFA).
Results: Plasma leptin was correlated to NEFA (r = 0.28) and glycerol (r = 0.48) concentrations. The relationship between %fat and plasma leptin was best fitted by an exponential (r2 = 0.82). In multiple regression %fat, body mass index, glycerol, and gender, but not fat mass, age or NEFA contributed independently to the variation in log plasma leptin. Log plasma leptin was higher in women than in men for a given glycerol concentration.
Conclusion: Adiposity, lipolysis, and gender are related to plasma leptin in healthy humans.