Studies on the metabolism of three BSP fractions in patients with constitutional jaundice

Conjugated sulfobromophthalein (BSP) in serum and bile were studied in 11 cases of constitutional jaundice. After 5mg/kg of BSP was injected intravenously, the chronological changes in BSP fractions in the serum were observed for 120 minutes or more. Serum BSP was separated into 3 fractions: free BSP (F-BSP), cysteine conjugated BSP (Cyst-BSP) and glutathione conjugated BSP (GSHBSP). In Dubin-Johnson syndrome, although serum F-BSP decreased gradually and GSH-BSP did not change, Cyst-BSP increased markedly with time (50% at 120min). GSH-BSP was not found in the bile. These suggest that the secondary rise of BSP in the serum is mainly due to gradual increase in Cyst-BSP which probably is the consequence of hydrolysis of GSH conjugated BSP, on account of impaired GSH-BSP excretion. Rotor's syndrome showed a marked retention of serum BSP, which consisted almost entirely of F-BSP. After 120 minutes, however, Cyst-BSP was markedly increased (73% at 24 hr). In this syndrome, therefore, impaired metabolism of conjugated BSP similar to that of Dubin-Johnson syndrome is thought to exist, as well as disturbed in BSP uptake. A variety of abnormal BSP metabolism was seen in cases of Gilbert's syndrome, suggesting that the syndrome may not be a single disease entity, from view-point of BSP metabolism.