Characterisation by high performance liquid chromatography of circulating growth hormone releasing factors in a human plasma.
Three forms of circulating immunoreactive human growth hormone-releasing factor (ir-hGRF) have been identified from a patient whose acromegaly was associated with a disseminated carcinoid tumour. This is the first known report of the molecular forms of ir-hGRF in human plasma. High performance liquid chromatography (HPLC) on a C3, wide pore reversed-phase column and gel filtration chromatography were used in conjunction with a sensitive radioimmunoassay (RIA). The greatly elevated concentration of the ir-hGRF in plasma from this patient was 25,000 ng/l (normal range less than 60 ng/l). Gel filtration (G50) chromatography of the plasma revealed a single peak which coeluted with synthetic hGRF-40. However, reversed-phase HPLC of Vycor-extracted plasma resolved the ir-hGRF into three components, which coeluted with synthetic hGRF-40 (69%), hGRF-44 (22%) and hGRF-37 (9%). At present it is not clear if the three forms are natural variants or whether either or both hGRF-40 and hGRF-37 are cleavage products of hGRF-44.
D000172:Acromegaly / Q000097:blood*; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D005260:Female; D013007:Growth Hormone-Releasing Hormone / Q000097:blood*; D006801:Humans; D008970:Molecular Weight; D010446:Peptide Fragments / Q000097:blood*; D011863:Radioimmunoassay
D010446:Peptide Fragments; C036893:somatotropin releasing factor 40; C040787:somatotropin releasing hormone (1-37); D013007:Growth Hormone-Releasing Hormone