Delta(9)-tetrahydrocannabinol increases proopiomelanocortin gene expression in the arcuate nucleus of the rat hypothalamus

Delta(9)-Tetrahydrocannabinol, the main psychoactive component of cannabis, produces a large spectrum of pharmacological effects, many of which have been linked to interaction with the opioid system. The aim of this study was to examine the effects of Delta(9)-tetrahydrocannabinol on proopiomelanocortin (POMC) gene expression in the arcuate nucleus of the hypothalamus and anterior lobe of the pituitary. We report, for the first time, that a 5-day treatment with Delta(9)-tetrahydrocannabinol (5 mg/kg per day, i.p.) increased (38%) POMC mRNA levels in the arcuate nucleus of the hypothalamus but was without effect in the anterior lobe of the pituitary. These data indicate that Delta(9)-tetrahydrocannabinol stimulates opioid gene expression and regulates distinctively POMC in the hypothalamus and the anterior lobe of the pituitary in the rat.