THE INFLUENCE OF DIFFERENT HORMONES ON BONE FORMATION IN RATS

Abstract

ABSTRACT Bone formation in rats has been evaluated by means of measurement of the retention in the bones of radioactive calcium given continuously with the food and determinations of the growth rate by means of repeated tetracycline labelling. In relation to age the retention of radioactive calcium in per cent of the intake varies in a manner similar to the growth and the increase in body weight in normal rats showing a rapid fall from the age of 3 to 6 months and from then on diminishing only slowly. During treatment with methyl-prednisolone growth practically stops and the retention of radioactive calcium is markedly reduced. At the same time a substantial loss in body weight takes place while the intake of food is comparatively little reduced. Treatment with methyl-androstenolone-oenanthat (Primobolan®) causes an increase in growth rate and weight gain. The retention of radioactive calcium was increased in 6 months old animals, although not in animals 9 months of age. This anabolic hormone did not, however, counteract the effect of methyl-prednisolone. No influence of growth or retention of radioactive calcium was observed following treatment with hog growth hormone (Somatropin®) or ovine prolactin (Prolaktin®).