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The work reported here was an attempt to determine the concentrations of thyroxine (T4) and tri-iodothyronine (T3) in the blood of the common toad (Bufo bufo). Few such results are available for cold-blooded animals.
The toads were pithed, pinned out supine, and the heart and its associated blood vessels were carefully exposed. Blood was obtained by puncturing the truncus arteriosus and applying suction, the blood collection apparatus having been previously heparinized. The yield was improved by tying off the aortic arches close to the heart and cannulating each aorta in turn with a flow of saline (Ringer's solution with 5% albumin added). The dilution thus caused was estimated from the haematocrits of the blood before saline was administered, and of the blood-saline mixture at the end of the collection. After centrifugation, the supernatant was stored at − 10° until required.
The supernatants from several toads were combined, adjusted
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SUMMARY
Isolated tissues of the toad Bufo bufo (urinary bladder, skin and kidney) were treated in vitro with thyroxine (T4) or tri-iodothyronine (T3) both with and without prior administration of the hormones in vivo. They were incubated at low temperature, and their oxygen consumption studied for 48 hr. Both hormones had little effect in vitro. Pretreatment with T4 in vivo usually lowered oxygen uptake; the effect of pretreatment with T3 varied. The presence of alanine in the incubating medium caused a marked increase in oxygen consumption. A seasonal effect was also found.
The respiration of isolated toad bladder was stimulated by a wide range of concentrations of thyroxine in vitro, and there were two peaks of stimulation.
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SUMMARY
Isolated tissues of the toad Bufo bufo were treated in vitro with thyroxine and triiodothyronine, and their oxygen uptake determined by conventional Warburg manometry. The respiration of the urinary bladder was stimulated by the hormones, and that of the kidney was reduced. Skin, heart, and muscle were affected to a lesser extent, the effect varying with dose and hormone.
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SUMMARY
A quantitative analysis of the iodoamino acids in whole dried parrot-fish thyroid gland was carried out by determination of stable 127I. Mono- and di-iodotyrosine together made up about half of the total iodoamino acids and thyroxine about a third to a half. The tri-iodothyronine content was low, about 5%. The total content of the acids increased with body weight, and there was an indication of a sex difference.
