Intestinal excretion of low and high molecular weight polyvinylpyrrolidone (PVP) in patients with proteinuria.

Abstract

Abstract. Excretion of polyvinylpyrrolidone (PVP) by the gastrointestinal tract has been investigated in a group of patients with proteinuria due to primary renal disease and a group of normal controls. Two types of PVP were used, one with a mean molecular weight of 40,000, labelled with 125I (LMW‐PVP), the other with a mean molecular weight of 160,000, labelled with 131I (HMW‐PVP). The purpose of this study was to obtain more information about the possibility of increased gastrointestinal protein loss in patients with proteinuria and, if present, to acquire data on its mechanism. In six of 30 patients PVP excretion was definitely above normal. Mean faecal PVP excretion was nearly twice as high as compared with the control group. The data obtained in this investigation point to a simultaneous involvement of the capillary wall in the gut in at least some of the patients with the nephrotic syndrome. A preferential excretion of the LMW‐PVP was shown in both groups, which indicates a sieving effect in the excretion of macro‐molecules. Faecal PVP excretion however appears to be less “selective” than urinary PVP excretion. A theory is developed to explain the gradually decreasing ratio