Serum levels of the adipocyte hormone leptin are increased in proportion to body fat stores
as a result of increased production in enlarged fat cells from obese subjects. In vitro studies
indicate that insulin and glucocorticoids work directly on adipose tissue to upregulate in a
synergistic manner leptin mRNA levels and rates of leptin secretion in human adipose tissue
over the long term. Thus, the increased leptin expression observed in obesity could result
from the chronic hyperinsulinemia and increased cortisol turnover. Superimposed upon the …