The effect of L-triiodothyronine on the growth and development of embryonic chick limb-bones in tissue culture / by Honor B. Fell and E. Mellanby.

  • Fell, Honor B.
Date:
[1956?]
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Licence: In copyright

Credit: The effect of L-triiodothyronine on the growth and development of embryonic chick limb-bones in tissue culture / by Honor B. Fell and E. Mellanby. Source: Wellcome Collection.

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    XReprinted from the Journal of Physioloqu, 1956, Yol. 133, No. 1, p. 89.] PRINTED IN GREAT BRITAIN J. Physiol. (1956) 133, 89-100 THE EFFECT OF L-TRIIODOTHYRONINE ON THE GROWTH AND DEVELOPMENT OF EMBRYONIC CHICK LIMB-BONES IN TISSUE CULTURE By HONOR B. FELL* and E. MELLANBYf From the Strangeways Research Laboratory, Cambridge, and the Nutrition Building, National Institute for Medical Research, Mill Hill, London (Received 16 February 1956) In the intact animal both hypo- and hyperthyroidism produce characteristic changes in the skeleton which have been observed both clinically and under experimental conditions; this work has been briefly considered in our previous paper (Fell & Mellanby, 1955). The experiments of Kaltenbach (1953) have shown that in amphibian embryos thyroxine can affect the developing limb- skeleton directly, since the implantation into one limb-rudiment of pellets containing thyroxine caused the bones to grow and ossify more rapidly than in the corresponding untreated limb of the same individual. It seemed likely that if the action of L-thyroxine on the skeletal tissues of warm-blooded animals were direct, then isolated bone rudiments in culture would be affected by thyroid active principles; as described in a previous publication (Fell & Mellanby, 1955) this proved to be true. The object of the present work was to study the effect of triiodothyronine (TIT) on bone rudiments cultivated in vitro, and to compare the action and potency of this hormone with those of thyroxine (T). TIT was discovered by Gross & Leblond (1951), and was identified in human plasma (1952) and synthesized (1953a) by Gross & Pitt-Rivers; in animal experiments it has usually proved by different criteria to be much more potent than thyroxine. Its antigoitrogenic action on rats treated with thiouraeil is several times as great as that of T (Gross & Pitt-Rivers, 19536; Heming & Holtkamp, 1953; Tomich & Woollett, 1954). In thyroidectomized rats its calorigenic effect is not less than 3-5 times that of T (Heming & Holtkamp, 1953), and in main¬ taining the growth-rate of such animals it is about 5 times as active (Gross & Pitt-Rivers, 19536). The potency of TIT is 3-T-7-5 times that of T in increasing * Foulerton Research Fellow, Royal Society. f Sir Edward Mellanby died before this paper was written, but he left notes on certain aspects of the work and some of these have been included. H. B. F.