DELTA(9)-TETRAHYDROCANNABINOL INCREASES PROOPIOMELANOCORTIN GENE-EXPRESSION IN THE ARCUATE NUCLEUS OF THE RAT HYPOTHALAMUS

Delta(9)-Tetrahydrocannabinol, the main psychoactive component of cann abis, produces a large spectrum of pharmacological effects, many of wh ich have been linked to interaction with the opioid system. The aim of this study was to examine the effects of Delta(9)-tetrahydrocannabino l on proopiomelanocortin (POMC) gene expression in the arcuate nucleus of the hypothalamus and anterior lobe of the pituitary. We report, fo r the first time, that a 5-day treatment with Delta(9)-tetrahydrocanna binol (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 ante rior lobe of the pituitary. These data indicate that Delta(9)-tetrahyd rocannabinol stimulates opioid gene expression and regulates distincti vely POMC in the hypothalamus and the anterior lobe of the pituitary i n the rat.