Abstract
On the basis of numerous biopsy specimens of the endometrium, in which substrates and enzymes concerned in the metabolism of glucose were examined in vitro, the following observations were made. Respiration and redox capacity as well as endogenous and exogenous glycolysis of the endometrium are increased maximally during the secretory phase. In this phase also the absolute Pasteur effect is increased to a maximum, while the control of glycolysis by the substrate is decreased. In addition, a Crabtree-effect appears at the same time. This suggests that the endometrium in the implantation phase endeavours to deliver constant amounts of ATP and to maintain a stable physico-chemical environment. While, from a gynaecological point of view various endometrium-associated disorders cause no notable differences in metabolism, the uptake of glucose, or respiration, cytochrome oxidase and succinate dehydrogenase activity in the secretory endometrium decrease with advancing age and thereby presumably diminish the fertility of the elderly woman. The use of oral contraceptives reduces the glucose metabolism from endogenous and from exogenous substrates in the endometrium, despite increasing synthesis of glycogen during the cycle. The reduction of metabolism occurs to such an extent that it must be expected that a contraceptive effect in the endometrium takes place.