CSF and serum concentrations of clozapine and its demethyl metabolite: a pilot study.

With the aim of exploring putative correlations between serum and CSF levels of clozapine and its demethyl metabolite, lumbar puncture was performed on four male and five female schizophrenic patients during long-term treatment with clozapine. Three consecutive 6-ml fractions were collected after at least 8 h of bedrest and fasting. On comparing serum and CSF levels, a correlation was found for norclozapine in the third (13-18 ml) CSF fraction. Norclozapine in the first (0-6 ml) CSF correlated significantly with height. The CSF/serum ratio of clozapine in the first fraction was correlated significantly with body weight. No correlations were found between serum levels of clozapine and norclozapine, or between the serum and CSF levels of clozapine. The study suffers from a small number of patients (for ethical reasons), but the present results might be explicable if the first (0-6 ml) CSF fraction represents a cul-du-sac of the CSF, mirroring the previous day's drug levels. The second fraction, then, will represent the CSF level in the steady state during the night.

Glucuronides of unconjugated 6-hydroxylated bile acids in urine of a patient with malabsorption.

The excretion of bile acids in urine from a patient with chronic malabsorption was investigated. Bile acids were separated according to mode of conjugation using a lipophilic anion exchanger, diethylaminohydroxypropyl Sephadex LH-20. Following hydrolysis, individual bile acids were analyzed by computerized GC/MS. In addition, bile acid glucuronides were isolated and their methyl ester trimethylsilyl ether derivatives were directly analyzed by GC/MS. The patient had a normal or slightly increased excretion of bile acids in urine. Bile acids carrying a hydroxyl group at C-6 constituted about 40% of the total. Tetrahydroxylated bile acids were present which have not been found in healthy subjects. Glucuronides of otherwise unconjugated bile acids accounted for 20% of the total. About 90% of these conjugates were 6-hydroxylated, hyodeoxycholic acid being the major bile acid. It is suggested that a specific abnormality of bile acid metabolism is related to the disease in this patient.

Analysis of plasma bile acid profiles in patients with liver diseases associated with cholestasis.

Bile acids in plasma of patients with intra- or extra-hepatic cholestasis have been analyzed by gas chromatography-mass spectrometry after fractionation into groups by mode of conjugation. During cholestasis plasma concentrations ranged from 14 to 252 mumol/l. The predominant bile acid was cholic acid, comprising 44% to 89% of total bile acids. Tetrahydroxy- and trihydroxy-cholanoates with a tentative 6-hydroxy structure were identified, whereas 1-hydroxylated bile acids were not found. 3 beta-Hydroxy-5-cholenoic acid was the most important monohydroxycholanoate, comprising up to 13% of total bile acids in serum. The ratio of cholic to chenodeoxycholic acid in patients with primary biliary cirrhosis was in all cases more than 1. With the exception of 1-hydroxylated bile acids the main bile acids in urine an plasma were the same. Renal clearance of individual conjugated and sulfated bile acids could be calculated for some of the patients, assuming insignificant metabolism of bile acids in the kidney. The renal clearance of cholic acid conjugates tended to be higher tna that of chenodeoxycholic acid conjugates, and sulfates of cholic acid conjugates tended to have a higher renal clearance than sulfates of chenodeoxycholic acid conjugates. The clearance of sulfated 3 beta-hydroxy-5-cholenoic acid was still smaller. Chenodeoxycholic acid predominated in two healthy persons. Unconjugated bile acids accounted for 30% and 53%, respectively, of total bile acids. Sulfates of lithocholic, allolithocholic, and 3 beta-hydroxy-5-cholenoic acids were found after stimulation with a test meal.

Prostaglandin F2alpha as a mediator of pulmonary changes during platelet aggregation.

Increases in pulmonary arterial pressure, tracheal insufflation pressure, and blood levels of the prostaglandin F2alpha metabolite, 15-keto-13, 14-dihydro F2alpha, were observed after protamine chloride or thrombin-induced platelet aggregation and release reaction in dogs. These effects were largely eliminated after administration of acetylsalicylic acid, an inhibitor of prostaglandin synthesis. The platelet aggregation was not noticeably affected. It is suggested that release of prostaglandin F2alpha from platelets is an important factor for the pulmonary changes during induced platelet aggregation. The necessity of measuring metabolite levels, rather than prostaglandin F2alpha levels, in blood during in vivo conditions is demonstrated.

Analysis of metabolic profiles of bile acids in urine using a lipophilic anion exchanger and computerized gas-liquid chromatorgaphy-mass spectrometry.

A method is described for quantitative analysis of bile acids in urine. Urine is acidified and bile acids are extracted on an Amberlite XAD-2 column. Bile salts are converted to acids on an Amberlyst A-15 column and are separated into groups of unconjugated, glycine, taurine, monosulfated, and polysulfated conjugates using the lipophilic anion exchanger diethylaminohydroxypropyl Sephadex LH-20 (DEAP-LH-20). After solvolysis and hydrolysis, the deconjugated bile acids are purified on DEAP-LH-20, and are converted to methyl ester trimethylsilyl ether derivatives. Identification and quantitation of the individual bile acids is accomplished by computerized gas-liquid chromatography-mass spectrometry. The daily excretion of bile acids in urine from healthy subjects was 6.4-11 micro moles. The mixture of bile acids was quite complex and differed from that in bile. About 30 bile acids were identified or partially characterized. Three of these were monosubstituted: lithocholic, allolithocholic, and 3beta-hydroxy-5-cholenoic acids. Fourteen disubstituted bile acids included epimers of deoxycholic, allodeoxycholic, chenodeoxycholic, allochenodeoxycholic, and hyodeoxycholic acids. 3alpha-Hydroxy-12-keto-5beta-cholanoic acid was the major ketonic bile acid and 3beta,12alpha-dihydroxy-5-cholenoic acid was the major unsaturated bile acid in this group. Nine trihydroxy bile acids included cholic and allocholic acids, epimers of these compounds, hyocholic acid, and a 1-hydroxylated bile acid tentatively characterized as 1,3,12-trihydroxycholanoic acid. Cholestatic subjects excreted tetrahydroxycholanoates carrying hydroxyl groups in positions 1, 3, 6, 7, 12, or 23. All monohydroxy and the predominant part of dihydroxy bile acids were present in the monosulfate fraction. Exceptions were 3alpha,12beta-dihydroxy- and 3alpha-hydroxy-12-keto-5beta-cholanoic acids, which were found mainly in the glycine conjugate fraction. Most of the trihydroxy bile acids were nonsulfated, and cholic and norcholic acids were the major unconjugated bile acids. The tetrahydroxy bile acids and hyocholic acid were present mainly in the taurine conjugate fraction, while 1,3,12-trihydroxycholanoic acid was predominantly found in the glycine conjugate fraction. Sulfation of trihydroxy bile acids was increased in patients with marked cholestasis. All bile acids in the monosulfate fraction were conjugated and carried the sulfate ester group at C-3. Significant amounts of di- and trisulfates were not found. The results indicate selective mechanisms for sulfation, hydroxylation, and renal elimination of bile acid conjugates. Analysis of metabolic profiles of bile acids in urine may be a useful method in studies of the function of organs involved in bile acid metabolism.