The metabolism of riboflavin in female patients with liver cirrhosis.

The metabolism of vitamin B2 was studied in five female patients with liver cirrhosis of varying etiology. Following the oral administration of 40 mg (106.3 mumol) riboflavin, plasma concentrations of riboflavin and flavo-coenzymes as well as urinary riboflavin excretion were analyzed over a period of 48 h. Results were compared to data obtained for healthy controls (Zempleni J. et al, Am. J. Clin. Nutr., 1996 [15]). About 18% of the administered vitamin was recovered from patients' urine, indicating an absorption similar to healthy subjects (p > 0.05). The area under the riboflavin plasma concentration vs time curve was 1.2-fold larger among patients than controls, but the difference was not significant (p > 0.05). Riboflavin peak concentrations in plasma (315.6 nmol/l) and times when those concentrations were achieved (3.0 h) were similar to those found for healthy subjects (p > 0.05). Flavocoenzyme peak plasma concentrations were increased 1.4-fold above their baseline levels in cirrhotics which was equal to controls (p > 0.05). 7 alpha-Hydroxyriboflavin was detected in the plasma of patients. Distribution and elimination kinetics of riboflavin were analyzed by using a two-compartment open model; the riboflavin plasma disposition rate constants of the patients (k alpha = 0.7232 h-1; k beta = 0.0627 h-1) were not different from controls (p > 0.05). No differences between both groups were found regarding renal excretion (renal clearance, first-order rate constants for renal excretion; p > 0.05). In conclusion, patients with liver cirrhosis of varying etiology and varying medical treatment did not show alterations of riboflavin turnover.