A.-R. Aedo

The effect of levonorgestrel administered in large doses at different stages of the cycle on ovarian function and endometrial morphology.

In a pharmacokinetic study, levonorgestrel (L-NOG) 0.75 mg was administered orally to 10 swedish women in the early follicular phase of the menstrual cycle. L-NOG levels were measured after L-NOG administration. A peak level of 16 nmol/l was reached after 2 hours, T 1/2 was estimated to be 14.5 hours (8.5-18.5) in the 24-48-hour interval after dosing. Seventy-two women (in Stockholm, Bombay and Shanghai) were assigned to 4 treatment groups and studied during a control cycle, a treatment cycle and a posttreatment cycle when 0.75 mg L-NOG was administered orally for 4 days in the follicular phase, periovulatory period or luteal phase. Peripheral blood was drawn 3 times weekly during the entire study for the assay of estradiol and progesterone. In 22 women in Stockholm, an endometrial biopsy was obtained on cycle day 20-22 in all 3 cycles studied. When L-NOG was administered on periovulatory days 9, 11, 13, and 15, 3 women showed follicular activity only, 7 exhibited follicular activity followed by insufficient luteal function and 7 women ovulated normally. When L-NOG was administered on periovulatory days 11, 12, 16 and 19, 7 women ovulated during treatment, 6 women exhibited follicular activity followed by insufficient luteal function and 5 exhibited follicular activity only. When L-NOG was administered in the follicular or luteal phase, no effect on ovarian function was seen. No significant prolongation of the cycle lengths was seen when L-NOG was taken during the follicular phase. Only minor effects in the endometrium were observed during treatment.

Pharmacokinetic and pharmacodynamic investigations with monthly injectable contraceptive preparations

Eight normally menstruating women received Cycloprovera (25 mg medroxyprogesterone acetate with 5 mg estradiol cypionate) and seven other volunteers received HRP-102 (50 mg norethisterone enanthate with 5 mg estradiol valerate) injections at 30-day intervals for three consecutive months. The peripheral plasma levels of estradiol (E2), progesterone (PROG), medroxyprogesterone acetate (MPA) and norethisterone (NET) were measured in the luteal phase of a pretreatment cycle, during the third treatment month and during a subsequent recovery period of 60 days. Blood samples were drawn three times a week (Mondays, Wednesdays and Fridays) and endometrial biopsies were taken on day 20 to 26 of the pretreatment cycle, 20 to 24 days after the last injection and 20 to 24 days after the first normal menstrual-like bleeding during the recovery period. The (geometric) mean maximum level of MPA was 2.9 (2.4-3.7) nmol/1 and that of NET 10.1 (6.4-15.8) nmol/l. Thirty days after the last injection, the MPA level was 0.72 (0.46-1.1) nmol/l and that of NET 1.7 (1.2-2.3) nmol/l. The maximum level of exogenous E2 was 890 (700-1130) pmol/l after Cycloprovera and 1570 (870-2820) pmol/l after HRP-102 administration. Forty-nine and 41 days, respectively, after the last injection, a broad (endogenous) E2 peak was observed in all subjects, which was not followed by an ovulatory rise in PROG levels. The first ovulatory rise in PROG occurred between 71 and 90 days after the last Cycloprovera and 59 to 87 days after the last HRP-102 injection. One subject in each of the two groups failed to ovulate during the 90-day post injection period. Dating and morphometric analysis of the endometrial biopsy specimens obtained 20 to 24 days after the last injection revealed that the suppressive effect of Cycloprovera was stronger than that of HRP-102. Each injection of both formulations was followed by a bleeding-free period of approximately two weeks. The percentage of days with bleeding and spotting was 24% for Cycloprovera and 29% for HRP-102. It is concluded, that both monthly injectables inhibit follicle maturation for some 30 days and ovulation and corpus luteum formation for some 60 days, providing thus a considerable margin of safety in terms of the expected duration of contraceptive protection.

Pharmacokinetics and biotransformation of orally administered oestrone sulphate and oestradiol valerate in post-menopausal women.

The pharmacokinetic properties and biotransformation of two orally active oestrogens, piperazine oestrone sulphate (PE1S, 2.5 mg/day) and oestradiol valerate (E2V, 2.0 mg/day), given alone or in combination with levonorgestrel (LNG, 250 micrograms/day) were compared in 8 post-menopausal women, using a randomized cross-over design. The end points measured in peripheral plasma included oestrone (E1), oestradiol (E2), oestriol (E3), oestrone sulphate (E1S), oestradiol sulphate (E2S) and oestriol sulphate (E3S). In addition, LNG and sex-hormone-binding globulin SHBG concentrations were also assessed. The plasma levels of E3 were invariably below the detection limit (220 pmol/l). The levels of all the other oestrogens analyzed were consistently higher and the area under the curve significantly greater (except in the case of E3S) following PE1S administration than those recorded after E2V ingestion. The terminal half-lives of the circulating oestrogens measured after PE1S administration did not differ from those found after E2V administration. After 21 days of PE1S administration (in combination with LNG for the last 10 days), the maximum levels of all the oestrogens (except those of E2) were significantly higher than those seen after the first dose. No such difference was observed after E2V administration. There was no difference between the effects of the two treatment regimens with regard to the E1/E2 ratios, but the E1/E1S ratios were significantly lower after PE1S treatment than after E2V administration. It is concluded that, compared with an equivalent dose of PE1S, daily repeated oral administration of E2V yields consistently lower peripheral plasma levels of E2 and its principal metabolites. However, in contrast to PE1S therapy, prolonged administration of E2V does not result in an accumulation of the circulating oestrogens measured.

Pharmacokinetic and pharmacodynamic effects of vaginal rings releasing levonorgestrel at a rate of 27 μg/24 hours: A pilot study

The pharmacokinetic and pharmacodynamic effects of vaginal rings releasing levonorgestrel (L-NOG) at an initial rate of 27 μg/24 h were studied in a group of 12 normally menstruating women during 90 days of continuous use (i.e., during three 30-day treatment segments). Blood samples were drawn immediately before insertion, 15 and 30 min, as well as 1, 2, 4, 8, 12 and 24 h after insertion of the rings, and thereafter three times weekly throughout the study for the analysis of L-NOG, estradiol, progesterone and sex hormone-binding globulin (SHBG). Endometrial biopsies were obtained for a morpho-metric analysis in a pre-treatment (control) cycle and in the 6th and 10th weeks of treatment. The peak of average L-NOG levels was reached within two hours after the insertion of rings. Until 24 h after insertion, the levels did not change significantly. Thereafter, a decrease at a rate of 0.2% per day was initiated. The L-NOG and SHBG levels were highly correlated. This was seen for both the pre-treatment SHBG vs L-NOG (r = 0.96) and the treatment SHBG vs L-NOG levels (r = 0.92). There was a significant (p < 0.001) decrease of SHBG levels due to treatment. During the total of 36 treatment segments, a normal ovarian function was seen in 47% of the segments. The women were anovulatory and had an inadequate lutal function in 28% and 25% of segments, respectively. No correlation between the L-NOG levels and ovarian reaction to treatment was found. The use of L-NOG induced significant changes in the endometrium; the number of glands/mm2 decreased after 6 (p < 0.02) and 10 weeks of use (p<0.01). Also, the diameter of glands and the occurrence of vacuolated cells decreased significantly (p < 0.02 and p < 0.005, respectively). None of the endometrial parameters or dating was correlated with the ovarian reaction to treatment, indicating independent endometrial effects of L-NOG.

Effect of orally administered oestrogens on circulating oestrogen profiles in post-menopausal women

The effect of 4 peroral oestrogen regimens without and with levonorgestrel (LNG) supplementation (250 micrograms/day) was studied in 7 post-menopausal women. The regimens were: A: 2.5 mg piperazine oestrone sulphate/day; B: 1.25 mg piperazine oestrone sulphate + 5.0 mg oestriol/day; C: 2.0 mg oestradiol valerate/day and D: 10.0 mg oestriol/day. A randomized complete cross-over design was employed and systemic blood levels of progesterone (P), oestrone (E1), oestradiol (E2), oestriol (E3), oestrone sulphate (E1S), oestradiol sulphate (E2S) and oestriol sulphate (E3S) were analyzed. All subjects were consistently post-menopausal, as indicated by low P, E2, E1S and E3S and high FSH and LH levels. The pretreatment and post-treatment levels of E2 and E2S as well as those of E3 and E3S were invariably below detection limit (60 pmol/l and 220 pmol/l, respectively). Treatment with regimens A, B and C resulted in consistently detectable levels of E2, E2S and E3S, but not of E3, and in grossly elevated E1 and E1S levels. Treatment with regimen D gave rise to very high E3S levels. The oestrogen profiles produced by regimens A and C were almost identical, with the exception of higher E1 and lower E3S levels following the administration of regimen A. Combination with LNG did not modify the levels of unconjugated oestrogens, but in certain cases it seemed to diminish those of oestrogen sulphates. A comparison with the results of a preceding study (Aedo A-R et al., Effect of orally administered oestrogens on gonadotrophins levels in post-menopausal women. Maturitas 1989; 11:) reveals that the gonadotrophin-suppressing effect of all 4 regimens still persisted in the post-treatment period at a time when the levels of all oestrogens analyzed returned to those of the pretreatment period.

Pituitary, ovarian and endometrial effects of graded doses of medroxyprogesterone acetate administered on cycle days 7 to 10

Eighteen apparently healthy women with normal menstrual cycles were studied during a control cycle and then during a treatment cycle, in which graded doses (2.5, 5.0 and 10 mg/day) of medroxyprogesterone acetate (MPA) were administered orally on cycle days 7 to 10. In both the control and the treatment cycle peripheral blood was drawn daily for the assay of luteinizing hormone (LH), estradiol (E2) and progesterone (PROG) and an endometrial biopsy was taken on cycle day 11. The lowest dose of MPA (2.5 mg X 4) did not influence the various cycle characteristics. Administration of higher doses (5.0 or 10 mg X 4) resulted in a lengthening of the duration of E2-peak (P less than 0.05), an increase in the area under the E2-peak (P less than 0.05), a decrease in the area under the PROG-curve (P less than 0.05) and a reduction in the height of the LH-peak (P less than 0.05). Furthermore, in 5 of these 12 subjects there was no ovulatory-like PROG-pattern during the cycle in which MPA was administered for 4 days. Morphometric analysis of the endometrial biopsy specimens revealed that the administration of MPA increased the diameter of endometrial glands (P less than 0.01) and the number of vacuolated glandular cells (P less than 0.001), decreased the number of glandular (P less than 0.01) and stromal (P less than 0.05) mitoses and reduced pseudostratification (P less than 0.001). There was no change in the number of endometrial glands and in glandular epithelial height. No leukocytic infiltration was observed. Dating of the biopsies indicated that all control biopsies were proliferative and all, but one (a suppressed proliferation including predecidual reaction), biopsies obtained after MPA administration were early secretory. The most conspicuous effect of MPA administration was a marked increase in subnuclear vacuolation, which could be demonstrated even at the lowest dose (P less than 0.01).

Pituitary, ovarian and endometrial effects of 300 μg norethisterone and 30 μg levonorgestrel administered on cycle days 7 to 10

Abstract The ovarian, endometrial and pituitary effects of 300 μg norethisterone (NET) and 30 fig levonorgestrel (L-NOG) administered orally on cycle days 7–10 were investigated in two groups of 10 women each, by daily analysis of plasma estradiol (E 2 ), progesterone (PROG), immunoreactive luteinizing hormone (LH) and follicle stimulating hormone (FSH) in a pretreatment control cycle and during NET or L-NOG administration. Endometrial biopsies were obtained for morphometric analysis on cycle day 11 in the control and treatment cycles. Treatment with 300 μg NET resulted in an increase in the area under the E 2 peak (p