The functions of the corpus luteum.—I. The mechanism of œstrus inhibition

Abstract

The effects on the occurrence of oestrus of the elimination and stimulation of the luteal tissue of the ovary have been studied. The postponement of the next oestrus by sterile copulation is not found in certain untreated, but abnormal, mice which fail to ovulate at oestrus, and which fail, therefore, to produce corpora lutea. Elimination of the corpora lutea by x-ray sterilization has a similar result in some instances, but in others secondary changes in the irradiated ovary obscure the result. It was previously shown that the ovary is responsible for the oestrus inhibition found in the mouse during lactation (Parkes and Bellerby). By means of a unilateral sterilization technique it is now shown definitely that the corpus luteum is the actual source of this inhibition. The luteal stimulating and indirectly oestrus-inhibiting effect of NaOH extracts of anterior pituitary is confirmed on the mouse. In the sterilized mouse the NaOH extract, finding no organized follicles to act upon, luteinizes most or all of the paren-chymatous proliferation of the germinal epithelium, which forms the bulk of the irradiated ovary. This luteinization results in the suppression of oestrus in the sterilized mouse. The process is, however, both his-tologically and physiologically reversible, and the cycle recommences after the end of injection.