Platelet and plasma serotonin concentrations in glomerulonephritis, II.

We studied intraplatelet serotonin and free plasma 5-OH indole ("serotonin") concentrations in patients with glomerulonephritis. Two hundred and sixty-two samples from 183 patients with primary glomerulonephritis of various types, 269 samples from 44 patients with SLE and 58 samples from 38 normal subjects were studied. Patients with minimal change lesions, focal and mesangial proliferative glomerulonephritis showed platelet and plasma serotonin concentrations indistinguishable from normal individuals. Patients with membranous nephropathy, mesangiocapillary glomerulonephritis, focal segmental glomerulosclerosis polyarteritis and systemic lupus, in contrast, showed diminished mean concentrations of intraplatelet serotonin and raised plasma serotonin concentrations. Within each group, there was a relationship between the two: the lower the platelet serotonin, the higher the plasma serotonin. The presence of a nephrotic syndrome or mild uremia (Pcreat < 400 mumoles/l) did not affect intraplatelet serotonin, although patients with severe uremia (Pcreat > mumoles/l) showed retention of plasma 5-OH indoles, and reduction in intraplatelet serotonin. These data provide further evidence for in vivo platelet activation in patients suffering from glomerulonephritis.