The effect of hypervitaminosis A on embryonic limb-bones cultivated in vitro / by Honor B. Fell and E. Mellanby.

  • Fell, Honor B.
Date:
[1952?]
Catalogue details

Licence: In copyright

Credit: The effect of hypervitaminosis A on embryonic limb-bones cultivated in vitro / by Honor B. Fell and E. Mellanby. Source: Wellcome Collection.

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    [Reprinted from the Journal of Physiology, 1952, Vol. 116, No. 3, p. 320.] PRINTED IN GREAT BRITAIN J. Physiol. (1952) 116, 320-349 THE EFFECT OF HYPERVITAMINOSIS A ON EMBRYONIC LIMB-BONES CULTIVATED IN VITRO By HONOR B. FELL (Foulerton Research Fellow, Royal Society) AND E. MELLANBY, F.R.S. From the Strangeways Research Laboratory, University of Cambridge, and the Nutrition Building, National Institute for Medical Research, London, N.W. 7 (Received 10 October 1951) Experiments on young animals have shown (Mellanby, 1938, 1939, 1944, 1947) that vitamin A determines the shape and texture of certain bones by controlling the position of the osteoblasts and osteoclasts of periosteal bone and the intensity of their activity. Both deficiency and excess of the vitamin cause severe changes in the skeleton, though the way in which the vitamin acts remains obscure. Some years ago a method was developed for cultivating early bone rudi¬ ments in vitro (Fell & Robison, 1929; Fell, 1951); the explants grew and con¬ tinued to differentiate in vitro in a surprisingly normal way. It occurred to Mellanby (1944) that such bone cultures might be used to study the action of vitamin A on skeletal tissue and especially to decide whether the action was a direct one. The method of cultivating organized tissues in vitro may be a valuable adjunct to animal experiments because of the great simplification of experimental conditions which it provides. In vitro there are no vascular or nervous systems, and the influence of other organs is completely eliminated; thus any effect produced by a chemical agent in vitro must be due to its direct action on the tissue. Also the experimental conditions can be widely varied at will and are more easily controlled in a tissue culture than in the body; the technique has the further advantage that the living explants can be observed under the microscope whenever desired. It was therefore decided to undertake experiments on the effects of hypervitaminosis A on embryonic long bones cultivated in vitro by the watch-glass method. In the living animal, hypervitaminosis A renders the long bones fragile, so that they sometimes suffer spontaneous fracture. This has often been observed in young rats fed on a diet containing an excessive quantity of vitamin A