Cholate radioactive

Urinary excretion of bile salts by healthy subjects is apparently very limited. The urine contained 2 % of the radioactivity administered orally as i C-cholic acid to a healthy subject in whom 100% of the radioactivity was recovered (80) and 0.12% of radioactivity administered to four normal subjects when i C-cholate was given intravenously (25). Conventional methods do not detect bile salts in the urine of healthy subjects (81,82). In jaundice patients, however, bile salts are excreted in the urine regularly (83). The highest 24-hr excretion rates reported by Gregg occurred in patients with common bile duct obstruction (58 mg/24 hr) and drug-induced cholestasis (40 mg/24 hr). The cholate/chenodeoxycholate ratio was greater than 0.59... 

Fig. 1. Composition of residual radioactivity in duodenal fluid obtained at the designated time periods after the intravenous injection of either taurocholate- C (R. A.) or glycocholate-i C (S. L.) into two student volunteers. Data are expressed in terms of percentage of radioactivity contributed by each bile salt fraction to the total recoverable radioactivity. GDC, glycodeoxy-cholate GC, glycocholate TDC, taurodeoxycholate TC, taurocholate.

Studies with radioactive glycocholate or taurocholate demonstrated a virtual absence of the enterohepatic circulation of bile acids in patients with jejunotransversocolostomy (77). The small amount of absorbed bile acids contained some deconjugated cholate and deoxycholate (which had been reconjugated in the liver), indicating a rapid bacterial action during an apparently fast intestinal passage. Under these conditions, steatorrhea is apparently not solely due to bile salt deficiency induced impairment of micelle formation, but reduced absorptive area may play an important contributory role. No direct measurement of bile acid synthesis by fecal determination has been performed in this condition. 

Partial separations of the substituted methyl allocholanoates have now been achieved by crystallization. Kallner (41, 45) has reported the removal of 82% of the radioactivity after three crystallizations of a mixture of methyl allolithocholate- H and methyl lithocholate 90% of the tritium was removed by several crystallizations of a mixture of methyl lithocholate- H and allolithocholate. Similarly, more than 90% of the radioactivity was removed from a mixture of methyl deoxycholate- H and allodeoxycholate after three crystallizations from aqueous acetic acid or aqueous methanol. Methyl 3/3,12a-dihydroxy-5 -cholanate was separated from methyl deoxy-cholate by crystallization from aqueous methanol. Thomas et al. (46) reported the separation of 3a,6/3-dihydroxy-5 - or 3a,6a-dihydroxy-5 -cholanoic acid from 3a,6/3-dihydroxy-5 -cholanoic acid by crystallization from aqueous acetone or a mixture of methanol, ether, and hexane. 

It was proved that the reaction effectively occurs within the liposome by radioactive labeling during glycogen synthesis, while the same reaction is prevented in the external medium. The authors additionally showed that DNase I and tRNA molecules could permeate through the POPC/cholate bilayer, but they also observed a critical size of about 70 kDa for which permeation is not possible (for instance, no permeation of phosphorylase and amyloglucosidase were observed). 

The radioactively labeled proteins of the mitochondrial membranes were separated using an amphipathic chromatographic system The stationary phase of this system is polymethacrylic acid resin, some of the carboxylic groups of which are linked to oleylamine by means of an amide bond (as outlined in Fig. 3). The mobile phase is a solution of the detergents cholate and deoxycholate. Thus, the mobile phase and the resin... 

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