Comparison of bile porphyrin concentrations in cattle and human beings with protoporphyria

Joseph R. Bloomer From the Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Box 36 UMHC, Harvard St at River Rd (Bloomer, Straka, Hill, Weimer) and the Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Minnesota, Minneapolis, MN 55455 (Ruth).

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James G. Straka From the Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Box 36 UMHC, Harvard St at River Rd (Bloomer, Straka, Hill, Weimer) and the Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Minnesota, Minneapolis, MN 55455 (Ruth).

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Hazel Hill From the Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Box 36 UMHC, Harvard St at River Rd (Bloomer, Straka, Hill, Weimer) and the Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Minnesota, Minneapolis, MN 55455 (Ruth).

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Mary K. Weimer From the Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Box 36 UMHC, Harvard St at River Rd (Bloomer, Straka, Hill, Weimer) and the Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Minnesota, Minneapolis, MN 55455 (Ruth).

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George R. Ruth From the Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Box 36 UMHC, Harvard St at River Rd (Bloomer, Straka, Hill, Weimer) and the Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Minnesota, Minneapolis, MN 55455 (Ruth).

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SUMMARY

Blood and bile porphyrin concentrations were measured in cattle with protoporphyria and compared with those in human beings with the disease. Whereas the mean rbc porphyrin concentration in cattle was 18-fold greater than in human beings, the mean bile porphyrin concentration was only 78% greater. Sequential measurements over a 30-hour period in 1 animal with a bile fistula indicated that the ratio of total porphyrin to total bile acid in bile varied minimally. When the animal was given an iv infusion of taurocholate, the biliary excretion rate of porphyrin increased in parallel with that of bile acid, because of enhancement of bile flow.

Thus, in cattle with protoporphyria, the concentration of porphyrin in bile is low compared with that of porphyrin in rbc, in contrast with findings in human beings, and adequate amounts of bile acids are secreted to maintain efficient protoporphyrin excretion. This explains, in part, why hepatobiliary disease has not been observed in cattle with protoporphyria, but has been seen in human beings with the disease.

SUMMARY

Blood and bile porphyrin concentrations were measured in cattle with protoporphyria and compared with those in human beings with the disease. Whereas the mean rbc porphyrin concentration in cattle was 18-fold greater than in human beings, the mean bile porphyrin concentration was only 78% greater. Sequential measurements over a 30-hour period in 1 animal with a bile fistula indicated that the ratio of total porphyrin to total bile acid in bile varied minimally. When the animal was given an iv infusion of taurocholate, the biliary excretion rate of porphyrin increased in parallel with that of bile acid, because of enhancement of bile flow.

Thus, in cattle with protoporphyria, the concentration of porphyrin in bile is low compared with that of porphyrin in rbc, in contrast with findings in human beings, and adequate amounts of bile acids are secreted to maintain efficient protoporphyrin excretion. This explains, in part, why hepatobiliary disease has not been observed in cattle with protoporphyria, but has been seen in human beings with the disease.

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