Endothelin in human brain and pituitary gland: Presence of immunoreactive endothelin, endothelin messenger ribonucleic acid, and endothelin receptors

The presence of immunoreactive (IR) endothelin, endothelin mRNA, and endothelin receptors in human brain and pituitary gland has been studied by RIA, Northern blot hybridization, and receptor assay. IR endothelin was detected in all five brain regions examined (cerebral cortex, cerebellum, brain stem, basal ganglia, and hypothalamus) (6–10 fmol/g wet wt) and spinal cord (22 ± 6 fmol/g wet wt, n = 7, mean ± sem). Higher concentrations of IR endothelin were found in the pituitary gland (147 ± 30 fmol/g wet wt). Fast protein liquid chromatographic analysis of the IR endothelin in pituitary gland showed a large IR peak in the position of endothelin-3 and a smaller peak in the position of endothelin-1, whereas IR endothelin in the hypothalamus and brain stem was mainly endothelin-1. Endothelin messenger RNA was detected by Northern blot hybridization in the pituitary but not in hypothalamus. The receptor assay showed that 125I-endothelin-1 binding sites were present in large numbers in all five brain regions b...