EFFECTS OF CONTINUOUS DAILY ADMINISTRATION OF 0.3 mg OF NOREHTINDRONE ON THE PLASMA LEVELS OF PROGESTERONE AND ON THE URINARY EXCRETION OF PREGNANEDIOL AND TOTAL OESTROGENS

Abstract

Daily determinations of the plasma level of progesterone and the urinary excretion of total oestrogens and pregnanediol were performed in 7 subjects during one control cycle, followed by three months of daily continuous treatment with 0.3 mg of norethindrone (NET). The control cycles were ovulatory according to the parameters investigated. During treatment there was a tendency to cyclically increased oestrogen excretion, this being most marked in cycles with very depressed progesterone-pregnanediol levels. All the subjects showed signs of cyclical luteal activity. In most cases, the levels of progesterone and pregnanediol were lower than during the corresponding control cycles. It is suggested that this might be due to deficient corpus luteum function. The drug had no thermogenic effect. The length of the treatment cycles varied between 22 and 49 days. Only two of the women showed intermenstrual bleeding. It seems that 0.3 mg of NET has a weaker effect on the hormone levels than 0.5 mg of NET, but a stronger effect than 0.5 mg of chlormadinone acetate.