H. Matsumoto et al., ENDOTHELIN FAMILY PEPTIDES IN HUMAN PLASMA AND URINE - THEIR MOLECULAR-FORMS AND CONCENTRATIONS, Peptides, 15(3), 1994, pp. 505-510
Molecular forms and concentrations of endothelin (ET) family peptides
in normal human plasma and urine were investigated using five differen
t sandwich-type enzyme immunoassays (sandwich-EIAs) and reverse-phase
high performance liquid chromatography (RP-HPLC). We found that immuno
reactive (IR-) big ET-3 and IR-big ET-2 were the major species in both
plasma and urine from normal humans. Big ET-2(1-38) was found to be t
he major form of IR-big ET-2 in plasma. Urinary IR-big ET-2 and plasma
and urinary IR-big ET-3 were heterogeneous, and the IR-big ET-3s were
larger (M(r) 6,000-12,000) than authentic big ET-3. IR-big ET-1, IR-E
T-1, and IR-ET-3 were found at relatively low concentrations in human
plasma and urine, and their major forms were identical to authentic bi
g ET-1, ET-1, and ET-3, respectively. Although ET-1 and other ET famil
y peptides have often been measured using RIAs with board-spectrum ant
ibodies, the presence of high concentrations of IR-big ET-2 and IR-big
ET-3, but not IR-ET-1, in plasma and urine indicates that the clinica
l significance of ET family peptides should be investigated with assay
methods specific to each ET and big ET.