Plasma catecholamines were fluorometrically determined by a modification of the standard alumina-trihydroxyindole method in which radioactive tracer catecholamines are used to follow the chromatographic behavior of the endogenous catecholamines on alumina. This modification permits appropriate fluorometry of that portion of the eluate with the highest concentration of catecholamines, because in...

Changes of free and sulfoconjugated catecholamines were measured radioenzymatically during a 5 minute period of acute asphyxia in chronically instrumented sheep fetuses (n = 5). Due to total reduction of uterine blood flow asphyxia as well as metabolic acidosis developed (pH = 6.94 +/- 0.02; Pco2 = 98 +/- 8 mmHG; lactate = 7.1 +/- 0.3 mmol/l). Peak concentrations of free catecholamines were rea...

This review describes experiments to produce antibodies towards the catecholamines and some catecholamine metabolites with the intention of developing radioimmunological methods. First, attempts to produce antibodies to the catecholamines themselves are described. In the course of synthesis of immunogens of catecholamines, it was necessary to exercise special care - e.g. the introduction of pro...

Comparative studies reveal that the ethylenediamine and the trihydroxyindole method when employed as suggested are suitable for assessing sympatho-adrenal activation under various stressful conditions that are accompanied by release of catecholamines into the circulation. Both methods are very accurate in quantitating epinephrine or norepinephrine that has been added to plasma or whole blood, a...

In this work, attention is focused on the non-essential amino acid L-Tyrosine (TYR) hydroxylated to L-DOPA, which precursor neurotransmitters dopamine, noradrenaline (norepinephrine; NE) and adrenaline (epinephrine; EP) known as catecholamines their interactions with redox-active Cu(II). Catecholamines have multiple functions in biological systems, including regulation of central nervous system...

Conjugated catecholamines in blood plasma of blood donors were determined from the difference between the total and the free catecholamines. Total catecholamines were measured after complete hydrolysis of the conjugated amines (heating of acidified samples for 40 min at 95 degrees C). Free catecholamines were determined in untreated plasma. Determinations were performed radioenzymatically. We c...

Quantitative determination of catecholamines and their O-methyl metabolites plays an important role in the diagnosis of pheochromocytoma (PHEO) – adrenal medulla tumour. This kind of tumour synthesizes, stocks, metabolizes and mostly secretes catecholamines. For this reason it is possible to use elevated concentrations of catecholamines and their metabolic products from plasma and urine as diag...

Adrenal chromaffin cells are an important part of the neuroendocrine system and under stressful conditions release catecholamines into the blood, thus regulating many physiological processes. In addition to the catecholamines, chromaffin cells also synthesize a range of peptides, including neuropeptide Y. Although the catecholamines and peptides are both contained within dense core granules, wh...

1. The effect of catecholamines (adrenaline, noradrenaline, and isoprenaline) in combination with ƒ¿and ƒÀ-blocking agents (phentolamine and propranolol) on pregnant mouse myometrium was investigated. The catecholamines had an inhibitory action in this tissue, the minimal dose required to produce inhibition being 3•~10-9 (g/ml) for isoprenaline, <10-7 for adrenaline, and <10-6 for noradrenaline...