查看文章

Leptin, the product of the ob gene, is a hormone secreted by adipocytes that regulates food intake and energy expenditure. The hypothalamus–pituitary–thyroid axis is markedly influenced by the metabolic status, being suppressed during food deprivation.The aim of the present study was to assess whether leptin can act as a metabolic signal connecting the adipose tissue with the pituitary–thyroid axis. We studied the effect of leptin administration (10 μg, i.c.v.) on spontaneous TSH secretion and TSH responses to TRH in euthyroid and hypothyroid food-deprived rats. Spontaneous TSH secretion was assessed over 6 h with samples taken every 7 min. Administration of leptin to food-deprived euthyroid rats led to a reversal of the inhibitory effect exerted by fasting on spontaneous TSH secretion. This stimulatory effect of leptin on spontaneous TSH appears to be dependent on the thyroid status since it could not be …