The metabolism of riboflavin in female patients with liver cirrhosis

The metabolism of vitamin B-2 was studied in five female patients with liver cirrhosis of varying etiology. Following the oral administration of 40 mg(106.3 mu mol) riboflavin, plasma concentrations of 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.