Measurement of sulfated and nonsulfated bile acids in human serum and urine

Amberlite XAD-2 was used to extract bile acids from urine or diluted serum of patients with hepatobiliary diseases. Columns containing Sephadex LH-20 were then used to separate the sulfated and nonsulfated bile acids. Thin-layer chromatography of the sulfated bile acid fraction obtained from urine revealed several spots with R(F) values different from those of the taurine or glycine conjugates. According to thin-layer chromatographic mobilities, gas-liquid chromatographic analyses, infrared spectra, and elementary analysis of the sulfated material, one of these sulfated bile acids was identified as glycochenodeoxycholic acid monosulfate, and the others were presumed to be taurochenodeoxycholic acid sulfate and glycocholic acid sulfate. A large amount of bile acid sulfate was found in urine of patients with hepatobiliary diseases. They accounted for 35.5-93.3% of total urinary bile acids and consisted of both di- and trihydroxycholanoic acids, with chenodeoxycholic acid as the major acid. Sulfated bile acids were also found in serum, and accounted for 1.8-21.2% of the total bile acids. Only dihydroxycholanoic acids (mainly chenodeoxycholic) were identified.

A simple method for the determination of serum free insulin levels in insulin-treated patients

A method for the determination of free, active insulin in the sera of insulin-treated diabetics is described. This involved radioimmunoassay after extraction of free insulin with polyethylene glycol. Recovery tests with cold insulin showed 73 per cent recovery of free insulin and no recovery of bound insulin.

The fasting free insulin levels were slightly lower in the patients than in normal persons; exceptions were some patients with complications expected to cause insulin resistance at the peripheral tissue level. Free insulin levels did not correlate with total insulin levels, antibody titers, insulin requirements or conditions of insulin treatment.

A very slight increase of insulin was observed after glucose loading in insulin-treated patients, but a marked increase of the free insulin level followed by an exaggerated increase in the total insulin level was observed in a patient with the insulin autoimmune syndrome.

The diurnal changes of the free insulin suggested the dynamic states of this fraction and its usefulness for determining control of diabetes with insulin.