抄録
Urinary excretion of albumin, apo A-I, and apo A-IV were quantitated in PAN (puromycin aminonucleoside)-induced nephrotic rats. Urinary albumin excretion was significantly correlated with the serum cholesterol concentration (r=0.777, p<0.01), although there was no negative correlation between the serum albumin and cholesterol concentrations. On the other hand, the renal clearance value of apo A-I was markedly lower than that of the albumin or apo A-IV. In addition, there was a positive correlation in the clearance values between the apo A-IV and albumin. This observation suggests that apo A-IV is more readily filtered through a glomerular basement membrane than apo A-I, whereas the molecular weight of apo A-IV is greater than apo A-I. This may be associated with the different forms of the serum of the two apolipoproteins.
The immunohistochemical findings showed that both apo A-I and apo A-IV were localized within the renal tubular cells, while apo B was absent in the control kidney. In the nephrotic kidney, on the other hand, apo A-I and apo A-IV were aggregated in the tubular lumen and apo B was present in the glomeruli. These observations confirmed that apo A-I and apo A-IV were readily filtered through the glomeruli while apo B continued to remain in the glomeruli even in the nephrotic kidney.
The present study revealed that apo A-IV was excreted into the urine in the nephrotic model, leading to a reduction in its serum level, as well as in the albumin.
