Physiology and pathophysiology of growth hormone-binding protein: methodological and clinical aspects.
Circulating GH is partly bound to a high-affinity binding protein (GHBP), which in humans is derived from cleavage of the extracellular domain of the GH receptor. The precise biological function GHBP is unknown, although a regulation of GH bioactivity appears plausible. GHBP levels are determined by GH secretory status, body composition, age, and sex hormones, but the cause-effect relationships remain unclarified. In addition to the possible in vivo significance of GHBP, the interaction between GH and GHBP has methodological implications for both GH and GHBP assays. The present review concentrates on methodological aspects of GHBP measurements, GHBP levels in certain clinical conditions with a special emphasis on disturbances in the GH-IGF axis, and discusses the possible relationship between plasma GHBP and GH receptor status in peripheral tissues.
Fisker
Sanne
S
Medical Department M (Endocrinology and Diabetes), Aarhus University Hospital, Aarhus Sygehus, Nørrebrogade 44, DK-8000 Aarhus C, Denmark. sanne.fisker@dadlnet.dk
D000818:Animals; D002352:Carrier Proteins / Q000097:blood / Q000502:physiology*; D006801:Humans; D008954:Models, Biological; D009928:Organ Specificity; D011986:Receptors, Somatotropin / Q000378:metabolism
D002352:Carrier Proteins; D011986:Receptors, Somatotropin; C051815:somatotropin-binding protein