Relationship between Hypothalamic-Pituitary-Adrenal Axis Function and Leptin Release.

The activation of sympathetic activity which is related to hypothalamic corticotropin-releasing hormone (CRH) release may modulate ob gene expression in vivo. In the present studies, we determined changes in circulating leptin concentrations by modulating sympathetic activity by adrenalectomy, corticosterone supplement, hypothalamic CRH infusion and starvation in male Wistar rats. Bilateral adrenalectomy significantly inhibited serum leptin concentrations and the continuous supplement of corticosterone by silastic tube restored the reduction of serum leptin concentrations in adrenalectomized rats. Intracerebro-ventricular infusion of 2μg recombinant rat CRH significantly decreased serum leptin concentrations at 2 hours after the infusion. In addition, 24-hour starvation significantly decreased retroperitoneal adipose tissue ob gene expression, measured by the reverse transcription-polymerase chain reaction (RT-PCR) method, and serum leptin concentrations. The data obtained herein indicated that the activation of CRH-ACTH axis by adrenalectomy, intracerebro-ventricular CRH infusion and starvation inhibits leptin production from adipose tissues and the reduced production of the anorexigenic message from adipose tissues may play a role in maintaining homeostasis in vivo by the disinhibition of hypothalamic feeding centers which is inhibited by hypothalamic CRH-containing neurons.