N-glycosylated variants of growth hormone in human pituitary extracts

This study was designed to investigate the existence, in human pituitary ex tracts, of growth hormone (GH) variants not encoded by the hGH-N gene. Usin g anion exchange-fast protein liquid chromatography followed by SDS-PAGE, w e isolated several basic forms of pituitary GH. Incubation of these basic f orms with endoglycosidase F/N-glycosidase F revealed that two of them (abou t 34 and 12 kD) were N-glycosylated. In contrast, no changes were found whe n samples were incubated with the O-linked glycosylation-specific O-glycosi dase. Since the GH-N molecule lacks consensus sequences for N-linked glycos ylation, our findings suggest that GH genes other than hGH-N are expressed in the human pituitary gland. Copyright (C) 2000 S. Karger AG, Basel.