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Eight bovine ovaries with a corpus luteum were perfused for 4 h in a haemoglobin-free semi-synthetic perfusion medium in a closed circuit. After an initial prolactin (PRL)-free perfusion phase, 4.7 ng/ml ovine PRL was added in the 1st h, followed by 47 ng/ml in the 2nd h and 470 ng/ml in the 3rd h. Glucose and oxygen consumption and the production of lactate, pyruvate and CO2 were measured, while perfusion pressure and pH-value were recorded continuously. Under the influence of PRL anaerobic glucose metabolism was stimulated by 40.5% and oxidative phosphorylation was inhibited. Energy production from aerobic glucose metabolism rose by only 0.25%. Unlike PRL, Human Menopausal Gonadotropin (hMG) and Human Chorionic Gonadotropin (hCG) stimulated aerobic metabolism. This may indicate that PRL is the "older" hormone in phylleogenetic terms.

Biochemical changes in the placenta were studied using alloxan-induced diabetes mellitus in the female rat. In comparison with a control group (n = 13) the placentas of the diabetic animals (n = 12) had significantly higher glucose, glycogen and protein levels. It was, however, shown that this supply of substrate was inadequately utilised for energy, as ATP/ADP quotient was lower and the ADP content was significantly higher. Metabolism still appeared to take place under aerobic conditions, as evidenced by the unchanged lactate levels. In terms of the protein content of the placentas, the activity of the enzymes we investigated (GOT, GPT, LDH, G-6-PDH, MDH, ICDH) was lowered by 25-44%. These results support the idea of global placental insufficiency in diabetics.