Effects of growth hormone on brain biogenic amine levels

The effects of IP administered bovine growth hormone (GH) on regional brain serotonin, 5-hydroxyindoleacetic acid (5-HIAA) and norepinephrine levels in rats were examined. GH decreased the levels of both monoamines and 5-HIAA in the diencephalon and brainstem while not affecting telencephalic concentrations. In hypophysectomized rats, however GH produced significant elevations of monoamine and 5-HIAA levels in all brain regions. In normal rats the decreases in norepinephrine content produced by GH were correlated with a reduction in the stimulatory action of d-amphetamine on general activity levels. These results demonstrate that GH can affect brain biogenic amines and that these effects have behavioral consequences.