EFFECTS OF DIFFERENT DOSES OF NORETHISTERONE ON OVARIAN-FUNCTION, SERUM SEX-HORMONE BINDING GLOBULIN AND HIGH-DENSITY LIPOPROTEIN-CHOLESTEROL

The ovarian effects of different doses of norethisterone (NET) were co mpared in 45 normally menstruating women in order to find the lowest e ffective dose of the Chinese NET ''visiting pill''. Subjects were rand omly divided into 3 groups. Each subject in each group was taking 0.5, 1.5 or 3.0 mg per day from days 5 to day 18 of the cycle. Blood sampl es were taken on days 5, 8, 11, 14, 17, 20, 23, 26 and 29 of the cycle . Serum oestradiol (E2), progesterone (P), sex hormone binding globuli n (SHBG), high density-lipoprotein cholesterol (HDL-C), and NET concen trations were measured. Ovulation, delayed ovulation, ovulation inhibi tion and follicular activity were classified by the analysis of the pe ripheral serum levels of sex hormones. Ovulation occurred in 7 women i n the 0. 5 mg group, in 2 women in the 1.5 mg group and in none of the 3.0 mg group. Mean serum SHBG levels were reduced progressively by 6. 6% (Group 0.5), 15.5% (Group 1.5) and 23.4% (Group 3.0). There were n o significant changes in HDL-C levels in any group. There was a signif icant correlation of mean serum NET concentrations with dose., The lac k of complete inhibition of ovulation in most women in the 1.5 mg and 0.5 mg groups might suggest that the dose of NET required when used as a visiting pill could not be reduced below 3.0 mg.