An increase in breathing activity has often been described for the secretory phase of the menstrual cycle, for gravidity and after intramuscular application of corpus luteum and follicle hormone. The reason for this has been assumed to be a direct interaction of the hormones in the respiratory center. A shortly published paper dealing with 50 women under long-term treatment with a combination of oestrogenes and gestagenes for oral contraception leads the author to the assumption, that a metabolic acidosis is the primary reaction, followed by an increase in breathing activity for respiratory compensation. In a long-term study it is difficult to differentiate between primary and secondary effects. Therefore in the present experiments arterial blood has been analyzed for PaO2, PaCO2, pH and hemoglobin in 49 subjects on day 1 without hormone administration and on day 2 prior to (9.00 a.m.) after (11.00 a.m., 1.00 p.m., 4.00 p.m.) administration of a combination of oestrogene and gestagene. From the measured values O2-saturation, standard-bicarbonate, buffer bases and base excess have been calculated by the Thews nomogram. By comparison of the results before and after hormone administration it was shown, that the primary effect is a metabolic acidosis, partly compensated during the next 7 h by respiratory adaptation. There is no indication for a primary respiratory alkalosis.
PIP: Immediate metabolic effects of Stediril and Eugynon, hormonal contraceptives containing 0.5 mg DL-norgestrel and 0.05 mg ethinyl estradiol, were studied in 39 women aged 18-43 years and 10 men aged 21-36 years. All subjects were volunteers who had taken no hormone preparations during the 3 months immediately preceding the study. Blood samples were taken at 9 and 11 AM and at 1 and 4 PM on 2 successive days; the contraceptive was administered immediately after the first sample was taken on the second day. From the measured values for arterial oxygen and carbon dioxide partial pressures, blood pH, and hemoglobin, values for oxygen saturation, standard bicarbonates, buffer abases, and base excess were calculated using the Thews nomogram. The primary effect of hormone administration was shown to be metabolic acidosis, which is partly compensated during the next 7 hours by the respiratory system. No signs of primary respiratory alkalosis were noted.