Occurrence of cholesterol and formation of oestrogen in the infantile rat ovary.

It has been shown that there is an intimate connection between the occurrence of cholesterol and the formation of oestrogen in the cells of the interstitial gland of the ovary, which are responsible for the synthesis of this hormone (Claesson 8c Hillarp, 1947). This connection seems actually to be of such a nature that the cholesterol must be regarded as a precursor of the oestrogen steroids (Claesson, Diczfalusy, Hillarp Sc H\l=o"\gberg,1948). Starting from this assumption, the infantile rat ovary seems to be of particular interest for illustrating the mechanism of oestrogen formation, as the oestrogen forming cells in this ovary show two stages in their relation to adequate gonadotrophic stimulation. At first they are completely uninfluenced but during their development, after a certain period, they acquire the property of responding to such a stimulus by oestrogen formation. It must therefore be regarded as important for the elucidation of the mechanism of oestrogen formation to investigate more closely the changes which occur in these cells in the transition between these two separate stages. As a first link in such an in¬ vestigation, an attempt has been made in the present work to study the relation between the occurrence of cholesterol, oestrogen formation and structural changes in the infantile rat ovary.