ISOLATION OF PEPSIN-RESISTANT LAMININ FRAGMENTS FROM HUMAN PLACENTA -EFFECT ON EPITHELIAL-CELLS CULTURED FROM THE KIDNEYS OF PATIENTS WITHAUTOSOMAL-DOMINANT POLYCYSTIC KIDNEY-DISEASE (ADPKD)

Laminin isolated from human placenta was subjected to prolonged pepsin digestion. Seven peptide fragments (designated N1 to N7) were separat ed by ion-exchange chromatography and gel filtration and characterised by SDS-polyacrylamide gel electrophoresis and immunoblotting. The mol ecular size of the laminin fragments varied from approx, 900 000 (N1) to 28 000 (N7). Epithelial cells obtained from normal kidneys and pati ents with autosomal dominant polycystic kidney disease (ADPKD) were cu ltured. The incorporation of [H-3]thymidine was measured over 96 h to determine the effect of the addition of the different fragments and wh ole laminin from EHS tumour to the cells. The rate of growth of both n ormal and polycystic cells was increased in the presence of the lamini n fragments but this effect was more pronounced in the ADPKD cells.