Heterogeneity of plasma motilin in patients with chronic renal failure.

Plasma immunoreactive motilin (IRM) concentrations were strikingly higher in patients with chronic renal failure (CRF) than in normal subjects. IRM in azotemic plasma was heterogeneous in gel-filtration profile. The first peak eluted in the void volume of the column and the second and the third one, comprising a major portion of IRM content, came out coincidentally with insulin and authentic motilin, respectively. By contrast, no discernible amount of IRM was found in the region corresponding with the second peak in gel-filtration of the plasma from normals and very little in a patient with ileus whole plasma IRM level was elevated. The hypermotilinemia and the accumulation of this high molecular weight motilin in patients with CRF suggest that the kidney plays some role in the elimination of motilin, and further, that the clearance of the high molecular motilin is more dependent on renal function than that of authentic motilin. The present paper emphasizes the necessity for clarifying the significance of the heterogeneity of IRM in CRF.