Sensitization of the skeleton to vitamin‐A overdosage by cortisol

The Influence of Hydrocortisone on the Action of Excess Vitamin a on Limb Bone Rudiments in Culture

“…The combined action of hydrocortisone or cortisone and vitamin A, however, is strikingly different in culture from that in the body: in the former the hormone retards and in the latter it accelerates the action of the vitamin on skeletal tissue. The accelerating influence of the hormone on the effect of the vitamin was first shown by Selye (1958) in rats, and in the Strangeways Laboratory similar results (unpublished) have recently been obtained by G. Weissmann on Xenopus larvae.…”

“…The retardative action of hydrocortisone on the changes produced by excess vitamin A in skeletal tissue in culture, contrasts sharply with the strongly additive effect of the two agents on the skeleton in the intact animal (Selye, 1958). It is suggested that this discrepancy between the results obtained in vitro and in vivo is probably due to systemic factors that operate in the body but are eliminated in organ cultures.…”

“…Our results show that in culture the hormone retards the effect of the vitamin on skeletal tissue. This suggests that the remarkable potentiation of the effect observed by Selye (1958) in animals treated with both agents together may have been due to systemic factors that are eliminated in organ culture.…”

“…It also accelerates the resorption of cartilage in vivo and in culture (Wolbach 1947;Fell and Mellanby, 1952) and removes the metachromatic material from the matrix Fell and Mellanby, 1952;Fell and Thomas, 1960), Selye (1958) found that the simultaneous administration of cortisone and excess vitamin A to rats produced extensive resorption of bone by the 20th day of treatment, a stage at which no effect is seen in animals given either agent alone; from this result he concluded that there is a "sensitisation of the skeleton to vitamin A overdosage by cortisol." In animal experiments, however, it is seldom possible to determine whether a given effect is produced by the direct action of an agent on a particular tissue, or whether it is due to indirect systemic reactions.…”

Développement du fémur pendant la période de lactation, chez des rats dont les mères ont subi, au 10e jour de gestation, un traitement en vitamine A

“…b) Une interaction hormonale est suggé rée par des images ressemblant à certaines réactions obtenues au cours d'expériences endocriniennes [Baume et al, 1953]. L'ac tion directe de la vitamine A sur les glandes surrénales a été établie par Selye [1958], Ershoff [1952] et Giroud et Ratsimananga [I960], Wolbach et al [1955], utilisant des rats adrénalectomisés recevant de la vitami ne A ou de la cortisone, ou les deux à la fois, ont montré la double action directe et indi recte, par l'entremise des surrénales, de la vitamine A sur l'ossification endochondrale. La même constatation pourrait s'appliquer à la thyroïde [Baumann et Moore, 1939] et à l'hypophyse [Wolbach et Maddock, 1952;Selye, 1957].…”