EXPERIMENTS ON THE GONADOTROPIC COMPLEX OF THE ANTERIOR LOBE OF THE HYPOPHYSIS

¹ Institute of Physiology, University of Concepción, Chile

The prehypophysis of the adult female rat or of the guinea-pig which causes strus but no ovarian changes and no luteinization in the infantile rat produces luteinization in the adult rabbit; this is indicative that the luteinizing hormone is present also in the non-luteinizing prehypophysis.

If an extract of the urine of the menopause having an strogenic action but not a luteinizing one (or only a very weak luteinizing one) is combined with the non-luteinizing prehypophysis, considerable luteinization takes place also in the infantile rat, a high coefficient of luteinization (Q_lut) being sometimes revealed.

As the prehypophysis, which alone does not luteinize in the infantile rat, contains the strogenic gonadotropic factor (action in the infantile rat) and the luteinizing one (action in the adult rabbit), the substance which is present in the gonadotropic extract of the urine of the menopause is supposed to be a new gonadotropic hormone acting after the

cestrogenic one and sensitizing the follicle so as to bring about its consecutive luteinization by the luteinizing hormone.

But since this substance found by us in the urine of the menopause is probably identical with that found by Evans, Meyer, and Simpson in the urine of pregnancy enabling a growth hormone preparation to luteinize, it may be that the relationship between the strogenic hormone, the new factor, and the luteinizing one is other as to the details than here expressed.

My thanks are due to Miss G. Hempel, to Dr E. Vinals, Mr E. Poch, and Mr G. Reyes, for the great help they have given me during the different phases of this work.