Studies of the Dipyrrylmethene (“Fuscin”) Pigments. I. The Anabolic Significance of the Fecal Mesobilifuscin*

Metabolism and Disposition of C14-Bilirubin in Congenital Nonhemolytic Jaundice*

“…Mesobilifuscin methyl ester was isolated from each fecal sample in amounts similar to those obtained from normal stool (22), but the pigment exhibited a specific activity of less than 10% of that of the serum bilirubin on corresponding days (Figure 1). Elemental Studies in rats Isotope turnover in vivo.…”

“…4) Fecal mesobilifuscin. Mesobilifuscin methyl ester was prepared by a modification of Siedel and M6ller's method (22). The purified dried pigment was used for elemental analysis and for assay of specific radioactivity (23).…”

Studies of the Dipyrrylmethene (“Fuscin”) Pigments. Iii. The Variable Fate of Bilirubin Depending Upon Conjugation and Other Factors*

“…Evidence obtained from studies with Nla-glycine, and a survey of a large number of patients with a variety of hematologic and hepatic disorders, has indicated that the dipyrrylmethene pigments such as mesobilifuscin are mainly anabolic in character, relating to heme synthesis rather than to hemoglobin destruction as formerly assumed (14,15). The idea that inability to recover significant quantities of tube-fed crystalline bilirubin as urobilinogen, or that discrepancies between the rate of hemoglobin breakdown and urobilinogen excretion might be reconciled by the measurement of Mbf, has been dispelled by the present studies.…”

“…Urobilinogen was determined by the method of Schwartz, Sborov and Watson (23), and mesobilifuscin (Mbf) by the modification of Siedel's method previously reported (14,15). In contrast to earlier procedures yielding a crude material of lower nitrogen percentage, this method has regularly provided material of a nitrogen content in agreement with theory (11).…”

“…Bilirubin was determined by the method of Malloy and Evelyn (24), adapted to feces. When crystalline N15-bilirubin was given, stercobilin and Mbf were isolated from the feces according to methods previously described (14,25). In three of these patients, 48-hour urine collections were made after administration of crystalline N15-bilirubin, and bilirubin was isolated from the urine (21).…”