Human fetal adrenal definitive and fetal zone metabolism of pregnenolone and corticosterone: alternate biosynthetic pathways and absence of detectable aldosterone synthesis.

In the rhesus monkey and ovine fetus in utero, aldosterone concentrations do not rise in response to surgical stress, ACTH, or angiotensin-II, all of which are secretagogues for this mineralocorticoid in the adult. To assess the mechanism of this phenomenon in the human fetus, metabolism of pregnenolone and corticosterone by second trimester human fetal adrenal definitive zone and fetal zone tissue was studied. After incubation of fresh tissue with trace amounts of [3H]pregnenolone or [3H]corticosterone, the products of metabolism were separated using high performance liquid chromatography and quantified. The delta 5-3 beta-hydroxysteroids 17-hydroxypregnenolone and dehydroepiandrosterone and their sulfates comprised 85-90% of metabolized pregnenolone. In the fetal zone, cortisol was the predominant secreted delta 4-3-ketosteroid, accounting for 6-8% of the metabolized pregnenolone. In the definitive zone, progesterone and corticosterone were the predominant secreted delta 4-3-ketosteroids, each accounting for about 2% of the metabolized pregnenolone. 11-Dehydrocorticosterone and sulfates were the only metabolites detected after incubation of fetal adrenal tissue with corticosterone. 11-Dehydrocorticosterone accounted for more than 80% of the metabolized corticosterone in the definitive zone and 50% in the fetal zone. Incubations with secretagogues or antioxidants (10 nmol/L ACTH, 10 nmol/L angiotensin-II, 21 mmol/L potassium, 100 mmol/L dimethylsulfoxide, 5 mumol/L metyrapone, or 100 mumol/L butylated hydroxyanisole) did not change the pattern or extent of precursor metabolism. No aldosterone, 18-hydroxycorticosterone, or 18-hydroxydeoxycorticosterone was detected in baseline or stimulated incubations of human fetal tissue. In contrast, adult human zona glomerulosa metabolized corticosterone to aldosterone, 18-hydroxycorticosterone, and 11-dehydrocorticosterone under similar conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

High-pressure liquid chromatographic determination of chloridazepoxide and its major metabolites in biological fluids.

A simple, isocratic, reversed-phase, high-pressure liquid chromatographic procedure was developed for the determination of chlordiazepoxide and its major metabolites in plasma and urine. The within-run coefficient of variation was 3.4-8.0%, and the day-to-day variation was 4.0-8.0%. Recoveries of 80-91% with sensitivity limits of 50 ng/ml were obtained for the parent drug and its metabolites. Plasma and urine samples collected after single intravenous and single oral doses were analyzed using this procedure.

High performance liquid chromatography-immunoassay of delta 9-tetrahydrocannabinol and its metabolites in urine.

High performance liquid chromatographic-immunoassay (HPLC-IA) profiles of cannabinoid metabolites in urine samples were obtained using four different antisera. The urines were chromatographed on a reverse phase system using a gradient of acetonitrile in water (pH 3.3) and fractions collected every 30 s. Some urine samples were hydrolyzed with methanolic sodium hydroxide before fractionation. Peaks of immunoreactivity were detected at a fraction corresponding to 11-nor-9-carboxy-delta 9-tetrahydrocannabinol (COOH-THC) and at an early eluting fraction; however, the profiles depended upon the specificity of the antisera used.

Concentrations of lidocaine and monoethylglycylxylidide (MEGX) in lidocaine associated deaths.

Concentrations of lidocaine and MEGX were determined in a variety of tissues and other samples collected at autopsy. In 13 of the cases examined in which lidocaine was associated with death, tissue concentrations were greater than 15 mg/kg. Tissue concentrations in other patients treated with lidocaine were significantly lower.

Capillary and packed column GC determination of propoxyphene and norpropoxyphene in biological specimens: analytical problems and improvements.

Several problems associated with the gas chromatographic determination of DPX and NDPX are discussed and an improved method for their extraction and quantification is described. The method involves two separate extractions, one for DPX with SKF 525A as the internal standard and one for NPDX with dinor-LAAM as the internal standard. The use of two internal standards improved quantitative reproducibility by almost 50%. It was also found that routine DPX and NDPX assays were better determined on packed columns than on capillary columns because the quality of the samples and of the columns was critical. The use of two IS and the double extraction procedure is recommended for general toxicological analyses.

Laboratory evaluation of immunoassay kits for the detection of cannabinoids in biological fluids.

The Center for Human Toxicology has, together with other toxicology laboratories, been involved in the field evaluation of a radioimmunoassay procedure for the detection and quantitation of delta 9-THC in serum and an enzyme multiplied immunoassay procedure for the detection of the nor-carboxylic acid metabolite in urine. Each laboratory was selected on the basis of proven experience with commercially available immunoassay procedures. Initially, the study was designed to screen samples collected from accident casualties; however, at some of the study sites the data base was extended to include other samples. The radioimmunoassay procedure evaluated was developed at the Receptor Research Institute, and involves the use of a tritium-labeled delta 8-THC tracer. A total of eight laboratories participated in the evaluation of this method, which is prepared in kit form by the manufacturer. Thirteen laboratories evaluated the EMIT procedure developed at Syva Corporation. The study protocol required that each site screen serum and urine samples and forward all presumptive positive specimens to the Center for Human Toxicology. These positive specimens were then shipped to either Battelle Laboratories or Research Triangle Institute for confirmation analysis by gas chromatography-mass spectrometry. The results of these evaluations will be presented and will include: 1. Correlations of positive RIA and EMIT analysis with gas chromatography-mass spectrometry results; 2. The results of quality-control tests; 3. Criticisms and suggestions made by analysts at each site; 4. The results of evaluations performed at the Center for Human Toxicology.