The long-term objectives of this research is to provide better understanding of the causes and treatment of unconjugated hyperbilirubinemia in man. During neonatal life and in certain individuals with the Crigler-Najjar Syndrome, Types 1 and 2, the concentrations of bilirubin in the circulation can reach levels that are associated with bilirubin encephalopathy. The basis for this disturbance is believed due to a delayed appearance or genetic absence of the glucuronyl transferase responsible for conjugation of bilirubin in liver microsomes. The Gunn rat is an animal model for this deficiency. The focus of the grant is the isolation of the normal and abnormal transferase enzyme from Gunn rat liver. The enzyme will be solubilized from liver microsomes, subjected to ammonium sulfate fractionation and purified by anion exchange, gel filtration and affinity chromotography. Amino acid and phospholipid composition studies are to be done on the normal and defective transferase. Normal and synthetic substrates will be used to better characterize the active site on the enzyme protein. The synthetic substrates are to be purified by high performance liquid chromatography as will the conjugation products. In vitro attempts will be made to correct the abnormal transferase from the jaundiced rat by both protein phosphorylations and dephosphorylations. Eventually the appearance and maturation of this transferase enzyme will be studied in fetal, neonatal and suckling animals.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK021668-11
Application #
3227074
Study Section
General Medicine A Subcommittee 2 (GMA)
Project Start
1978-02-01
Project End
1989-05-31
Budget Start
1987-06-01
Budget End
1988-05-31
Support Year
11
Fiscal Year
1987
Total Cost
Indirect Cost
Name
University of Wisconsin Madison
Department
Type
Schools of Medicine
DUNS #
161202122
City
Madison
State
WI
Country
United States
Zip Code
53715
Trost, G R; Nagatani, K; Goknur, A B et al. (1993) Bilirubin levels in subarachnoid clot and effects on canine arterial smooth muscle cells. Stroke 24:1241-5
Letarte, P B; Lieberman, K; Nagatani, K et al. (1993) Hemin: levels in experimental subarachnoid hematoma and effects on dissociated vascular smooth-muscle cells. J Neurosurg 79:252-5
Odell, G B; Mogilevsky, W S; Smith, P B et al. (1991) Identification of glutathione conjugates of the dimethyl ester of bilirubin in the bile of Gunn rats. Mol Pharmacol 40:597-605
Shore, L J; Mogilevsky, W S; Smith, P B et al. (1991) In vitro formation of glutathione conjugates of the dimethylester of bilirubin. Biochem Pharmacol 42:1969-76
Odell, G B; Mogilevsky, W S; Gourley, G R (1990) High-performance liquid chromatographic analysis of bile pigments as their native tetrapyrroles and as their dipyrrolic azosulfanilate derivatives. J Chromatogr 529:287-98