Relationships between serum levels of prolactin oestrogens LH FSH and progesterone during menstrual cycle and treatment with steroids. (Abstract only)

Daily plasma prolactin luteinizing hormone (LH) follicle stimulating hormone (FSH) estrogens and progesterone were radioimmunoassayed in 10 women for 2 cycles the 2nd cycle during intake of ethinyl estradiol 50 or 400 mcg d-norgestrel . 25 or 2.5 mg and norethisterone acetate 50 mcg for 21 days. In the control cycles midcycle LH peaks of 99.2 mIU/ml and secondary LH peaks in 9 luteal phases occurred. FSH was higher in follicular phase 6.2 mIU/ml than in luteal phase 3.4 and peaked at 11.7 with LH. Estrogens rose from Day -9 peaked on Day -1 260 pg/ml then fluctuated usually peaking on Days +3. Progesterone peaked on Days +4 and +7. Prolactin resembled estrogens from Day -9 171 mU/ml to Day +2 202 peaking on Day -1 at 373 Day +5 at 301 and Day +7 at 303 mU/ml. All treatments abolished progesterone secretion. .25 mg norgestrel caused inconsistent responses. 2.5 mg norgestrel inhibited LH and enhanced FSH. 10 mg norethisterone produced a few LH surges then basal LH levels. 50 mcg ethinyl estradiol caused irregular surges of LH FSH and estrogens over normal basal level but average 1.1- to 1.9-fold higher prolactin levels. 400 mcg ethinyl estradiol caused LH FSH and estrogens to surge briefly then fall while prolactin ranged 2-5 times higher than in control cycles.