Regulation of activator protein-1-DNA binding activity by opioid peptides in estrogen-sensitive cells of rat hypothalamus and uterus

The present studies demonstrate, for the first time, that the binding of ac tivator protein-1 (AP-1)-DNA in rat uterus and the estrogen-sensitive areas of the hypothalamus, as measured by electrophoretic mobility shift assay, is increased 2 h after intraperitoneal injection of [D-Met(2),Pro(5)]enkeph alinamide. The effect was prevented by the opiate antagonist naltrexone giv en 30 min before the administration of [D-Met(2),Pro(5)]enkephalinamide. su ggesting the involvement of opioid peptide receptors in the observed effect s. The present findings support the role of opioid peptides in the regulati on of transcription in estrogen-sensitive cells. (C) 2000 Published by Else vier Science B.V. All rights reserved.