Further studies on the characterization of a renotropic activity detected in uninephrectomized rat plasma.
Using chromatographic techniques, we have purified a peptide responsible, at least in part, for the renotropic activity detected in 24-hour uninephrectomized adult rat plasma. The most purified material behaved as a single component when analyzed by reversed-phase HPLC. The purified factor stimulates DNA synthesis in isolated rat proximal tubules and proximal tubular cell (LLC-PK1) cultures. This effect was abolished by pretreatment with protease K, with an intracellular calcium chelator or with indomethacin. This factor was also mitogenic for rat mesangial cells. In contrast, neither Madin-Darby canine kidney cells nor rat liver cells responded to the growth factor. Using the same purification procedure, a bioactive factor with an amino acid composition almost identical to that of this renotropic peptide was isolated from sham-operated or normal rat plasma. However, only uninephrectomized plasma after gel filtration showed renotropic activity, which was inhibited by the corresponding chromatographic fraction from sham-operated plasma. Our findings suggest that a change in the concentration of a circulating inhibitor(s) appears to account for the differences in the activity of sham-operated or control plasma and uninephrectomized plasma on the growth of renal cells.
García-Ocaña
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Metabolic Unit Research Laboratory, Fundación Jiménez Díaz, Madrid, Spain.
Esbrit
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P
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000378:metabolism; D019286:Endopeptidase K; D006133:Growth Substances / Q000097:blood* / Q000494:pharmacology; D036341:Intercellular Signaling Peptides and Proteins; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000378:metabolism; D008297:Male; D009392:Nephrectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D012697:Serine Endopeptidases / Q000494:pharmacology
D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; C010320:renotropins; D004247:DNA; D012697:Serine Endopeptidases; D019286:Endopeptidase K