Separation and Quantitative Recovery of Iodinated Amino Acids and Iodide by Thin-Layer Chromatography.

Abstract

FIG. 4. Changes in blood glucose and plasma NEFA levels in response to epinephrine infusions. I.V. injection of propranolol is shown by the arrow.Prior to blockade, epinephrine had little effect on arterial blood presure, but increased the cardiac output. Following blockade the arterial pressure was greatly increased and the heart rate and cardiac output decreased. This is explained by the fact that epinephrine is an agonist of both alpha and beta receptors. When the latter are blocked, activity at the former predominates, resulting in intense peripheral vasoconstriction, hypertension and slowing of the heart. That the slowing was reflexly induced was clear from the fact that it did not occur in atropinized dogs.Release of NEFA from adipose tissue stores is to a large extent under the control of the sympathetic nervous system. Infusions of epinephrine (9) and norepinephrine ( 10) cause temporary increases in plasma NEFA levels. Most authors( 1 1 , 1 2 ) found that pronethalol prevented the catecholamine-induced increase from occurring. However, Riggilo and Kyam( 13) reported that, although pronethalol blocked the hyperglycemic effect of catecholamines in dogs, it failed to inhibit the increase in NEFA levels. In our studies, propranolol consistently and completely blocked the release of NEFA by epinephrine even when its hyperglycemic effect was not completely abolished.

Comparison of Paper and Thin-Layer Radiochromatography for the Quantitative Analysis of Thyroidal Iodoamino Acids

“…The claims made for TLC by Sofianides et al (1966) have been confirmed and it has proved of value in the quantitative analysis of thyroidal compounds resulting from thyroid stimulation. The degree of separation, reproducibility and reliability have led us to prefer thin-layer to paper chromatography.…”

“…Separation by TLC was invariably excellent when the time for the run in the first direction was increased from 4 hr. (Sofianides et al 1966) to 16 hr. and differ¬ entiated clearly between T3 and T4.…”

“…Thus, it was possible to compare the two Chroma¬ tographie methods on samples in which the proportions of the labelled compounds differed by amounts similar to the variations likely to be encountered under other experimental conditions. Faircloth, Williams & Florsheim (1965) and Sofianides et al (1966) have applied TLC methods to the investigation of rat thyroid hydrolysates. In this study a TLC method has been satisfactorily applied to analyse quantitatively the response of the mouse thyroid gland to stimulation by TSH.…”

“…Recently thin-layer chromatography (TLC) has been recommended by Hollingsworth, Dillard & Bondy (1963) and West, Wayne & Chavré (1965) for its speed, convenience and good separation. In addition to the improved separation it has been claimed that the method offers good recovery and reproducibility (Sofianides, Meloni, Alger & Canary, 1966) and that there is less deiodination than with paper (Shapiro & Gordon, 1965). This study compares paper and thin-layer chromatography.…”

The Influence of Adrenergic Receptor Blocking Agents on the Mouse Thyroid

“…Aliquots of the digest were spotted on to the plates. The two dimensional system of Sofianides, Meloni, Alger & Canary (1966) was used: for.the first direction the solvent was tertiary butanol: 3 % NH 40H (3: 1 v/v) and the development time 4 h; the second solvent was secondary butanol: glacial acetic acid: water (4:4: 1 v/v) and development time 40 min. lodoamino acids were stained with 0·25 %ninhydrin in acetone and iodide was stained with 0·1 %PdCI 2 • The spots, including the origin, were scraped into polythene counting vials and counted in a well scintillation counter (EKCO); each spot was counted twice.…”