INFLUENCE OF REPRODUCTIVE HORMONES UPON GROWTH IN OVARIECTOMIZED AND NORMAL FEMALE RATS

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Abstract
The effect of reproductive hormones upon the growth rate of pre-pubertal and post-pubertal ovariectomized and normal rats was investigated. Physiological quantities (10 I. U./day) of injected estrone retarded the growth rate in every case, but the relative degree of retardation was greatest in those rats in which the rate was at a maximum. That quantity of estrone necessary to retard the growth rate of ovariectomized post-pubertal rats to that of the unoperated controls (10 I. U./rat/day) was adjudged to be within the normal physiological level. In contrast to estrone effects, progesterone accelerated the growth rate and the relative rate of acceleration was greatest when administered to rats with a minimum rate of growth. This effect of progesterone was observed whether it was injected or was systemically produced in pseudopregnancy, pregnancy, or by the inj. of a chorionic gonadotrophm. However, pregnancy yielded the greatest stimulus to growth. The fat and water content of all groups of rats were not significantly different indicating that factors other than abnormal accumulations of either of these substances were responsible for the growth changes.