Serum somatomedin A in chronic renal failure.

The serum levels of somatomedin A, determined by radioreceptor assay, were significantly higher in 57 adult patients with chronic renal failure (X = 2.57 +/- 0.12 U/ml) than in healthy subjects (n = 131; X = 0.77 +/- 0.02 U/ml). A positive correlation was found between somatomedin A and creatinine levels (r = 0.33), but somatomedin A levels did not decrease after hemodialysis. A reduction was only observed after successful renal allografting. Immunoreactive somatomedin A was also found to be increased in patients with chronic renal failure (X = 2.61 +/- 0.21 U/ml), whereas low levels were obtained by the chick bioassay. However, after separating the inhibitory factors from the stimulatory factors by gel chromatography at neutral pH, uremic serum was shown to contain increased levels of somatomedin activity. Although all somatomedin A, determined by different techniques, was present in high molecular forms, the elution pattern differed from that seen in patients with acromegaly.