Abnormalities in liver function and morphology and impaired aminopyrine metabolism in hereditary hepatic porphyrias.

The aminopyrine breath test and measurement of postprandial serum bile acids were performed in 67 patients with well-documented hereditary hepatic porphyria. Elevated postprandial serum bile acids levels were found in 75% and the aminopyrine breath test was abnormal in 42% of the patients studied. These function tests exhibited a statistically significant correlation with the excretion of porphyrin precursors in patients with acute intermittent porphyria. Furthermore, all 12 patients with acute intermittent porphyria who had a liver biopsy because of abnormalities in the aminopyrine breath test or postprandial serum bile acids measurement, or both, were found to have diffuse, moderately severe, but nonspecific ultrastructural changes of hepatocytes, indicative of significant subcellular damage. While a direct relationship between functional and morphologic abnormalities is speculative, it is possible that the defective heme biosynthesis, perhaps related to the reduced aminopyrine demethylation, could form the basis for the ultrastructural hepatic changes in porphyria. This, in turn, could be the cause of the elevated postprandial serum bile acids levels.