Comparative studies of the ethynyl estrogens used in oral contraceptives. VII. Effects with and without progestational agents on ultracentrifugally fractionated plasma lipoproteins in humans, baboons, and beagles.

Ethynyestradiol and mestranol, in doses ranging from 50 to 100 microgram/day, were given to women in 21-day cycles; baboons and beagle dogs received 1 and 4 microgram/kg/day in a similar regimen. After a number of such cycles, megestrol acetate, norethindrone acetate, or dl-norgestrel was given concomitantly. Protein, cholesterol, triglyceride, and phospholipid levels were determined in total plasma and in ultracentrifugally separated lipoprotein fractions. Over the dosage range studied, the effects of the two kinds of estrogen were indistinguishable. Except for human total plasma triglyceride, no dose-related differences were observed. The lowering of serum protein and the increase in cholesterol induced by estrogen were more pronounced in baboons and beagles than in human subjects. The cholesterol-depressing effect of progestational compounds observed in humans was very pronounced in baboons but absent in beagles. In all three species, estrogen increased the lipoprotein fraction cholesterol, except for human low-density lipoprotein cholesterol, which was decreased. Human plasma triglyceride and phospholipid increased on estrogen administration and were decreased by the progestins; in the two animal species, triglyceride is normally very low and the estrogen-induced changes were negligible; the phospholipid rose with estrogen but was unaffected by progestins. In sum, the two animal species show many similarities to, as well as important differences from, the human response of plasma lipids to various contraceptive steroids.

PIP: In this comparative study, ethinyl estradiol and mestranol (dose range, 50-100 microg/day) were given to women in a 21-day cycle; baboons and beagle dogs received 1 and 4 microg/kilog/day in a similar regimen. After a number of cycles, mestranol acetate, norethindrone acetate, or d,1-norgestrel was given concomitantly. Protein, cholesterol, triglyceride and phospholipid levels were determined in total plasma and in ultracentrifugally separated lipoprotein fractions. Effects of the 2 kinds of estrogens were indistinguishable over the dosage range studied. Except for human total plasma triglyceride (P .001), no dose-related differences were observed. Lowering of serum protein and increase in cholesterol induced by estrogen were more pronounced in the 2 animal species than in humans. The cholesterol-depressing effect of progestational compounds observed in humans was very pronounced in baboons but was absent in beagles. In all 3 species, estrogen increased the lipoprotein fraction cholesterol, except for human low-density lipoprotein cholesterol, which was decreased. Human plasma triglyceride and phospholipid increased on estrogen administration and were decreased by progestins. In beagles and baboons, triglyceride is normally very low and the estrogen-induced changes were negligible; phospholipid rose with estrogen but was unaffected by progestins.

Comparative studies of the ethynyl estrogens used in oral contraceptives: effects with and without progestational agents on plasma androstenedione, testosterone, and testosterone binding in humans, baboons, and beagles.

The effects of ethynylestradiol or mestranol given in cyclic fashion, with and without a progestational compound (norethindrone acetate, dl-norgestrel, or megestrol acetate), on plasma androgens and their binding were examined in adult women, female baboons, and beagles. The two estrogens are equivalent in their effect, and there were essentially no dose-related differences over the range examined. In human subjects, the estrogens increased total testosterone and testosterone binding, and decreased free testosterone. In baboons, estrogen produced a transient decrease in total testosterone and an increase in binding. The levels of progestational agents used did not affect total testosterone in humans, as is commonly observed with commercial agents, but did decrease it in baboons. Percentage binding was decreased in both species by the 19-nor compounds, but not by megestrol. Androstenedione levels were unaffected in human subjects, but effects of both estrogens and progestins were seen in baboons. Because of the very low levels of androgens in female beagles, this species did not lend itself well to a study of this kind. However, an increase in testosterone binding was induced by estrogen even in the absence of testosterone/estrogen-binding globulin.

Comparative studies of the ethynyl estrogens used in oral contraceptives. VI. Effects with and without progestational agents on carbohydrate metabolism in humans, baboons, and beagles.

Human subjects, baboons, and beagles were given cyclic regimens of ethynylestradiol or mestranol; after a number of such cycles, concurrent administration of norethindrone acetate, dl-norgestrel, or megestrol acetate was introduced for a similar number of cycles. Carbohydrate tolerance was evaluated by oral glucose tolerance testing in the human subjects and by intravenous glucose tolerance testing in the baboons and beagles. In the human subjects, neither mestranol nor ethynylestradiol at daily doses of 50 to 100 microgram/day produced any effect on fasting glucose levels or on glucose tolerance even after six cycles of treatment. The addition of the progestational compounds also had no effect on these two variables. In baboons, ethynylestradiol and mestranol were bioequivalent and produced a dose-related decrease in the glucose disposal rate. All three progestational agents counteracted this effect in a comparable manner. In beagles, on the other hand, estrogens produced an increase in the glucose disposal rate, and the addition of progestational agents produced an initial fall and a subsequent return to pretreatment levels.

PIP: In a comparison of the glucose metabolic effects of certain estrogens and progestins, 163 normal females received either 50 or 80 mcg/day ethinyl estradiol or 50, 80, or 100 mcg/day mestranol for 21 days over 6 cycles. At the end of 6 cycles each group received additionally either 2.5 mg/day norethindrone acetate, 2 mg/day megestrol acetate, or .5 mg/day dl-norgestrel. Simulations of this regimen were carried out in beagles and baboons using lower dosages and treatment durations of 4 instead of 6 cycles. Glucose tolerance tests were administered orally to the humans and iv to the animals in the latter part of certain treatment cycles. In humans, no significant effects were found for type or dose of estrogen, cycle number, addition of progestin, or any of their interactions. In the animals, estrogen lowered fasting plasma glucose both in the baboons (p .05) and in the beagles (p .001), a trend which reversed spontaneously until control values prevailed at the end of the 4th estrogen-treatment cycle. Progestins had no effect. Glucose assimilation rates (K values) were significantly depressed over the first 4 cycles in baboons (p .001) but rose with the addition of progestins. In beagles, by contrast, the K values rose (p .001) and fell again with the introduction of progestin treatment. It is concluded that baboons and beagles are poor models for examination of human carbohydrate metabolism.

Radioimmunoassay of unconjugated plasma ethynylestradiol in women given a single oral dose of ethynylestradiol or mestranol.

A method for the radioimmunoassay of ethynylestradiol in plasma is described. The sensitivity is 18 pg/ml, recovery 86.5%, and precision 10.9% (coefficient of variation). Normal women, five at each dose level, were given 50 or 80 mug ethynylestradiol or 50, 80, or 100 mug mestranol of uniform bioavailability. Peak plasma levels were consistently obtained in the 1-hour plasma sample with the former compound. With mestranol, the peak levels of ethynylestradiol were lower than with the same quantity of ethynylestradiol and the time-curve of plasma levels much more variable. With this procedure, it is now possible to study certain aspects of the pharmacokinetics of these clinically important compounds.

PIP: 25 healthy women of reproductive age who had not previously used oral contraceptive steroids, were each given a single tablet containing 50, 80, or 100 mcg of mestranol or 50 or 80 mcg of ethinyl estradiol. Blood samples were obtained before taking the tablets and at intervals of 1, 2, 4, and 24 hours afterward. Anti-ethinyl-estradiol antibody in 1 to 100,000 initial dilution was used. Details of techniques employed are given. With ethinyl estradiol, the 1-hour sampling yielded the maximum plasma levels. At 24 hours, the plasma level was not detectable in 4 of 5 subjects given 50 mcg or in 1 of 5 given 80 mcg. With mestranol, the disappearance curve was more variable with the peak levels usually at 2 hours but occasionally at 4 hours. At all 3 dose levels of mestranol, measurable serum ethinyl estradiol levels were found at 24 hours. These levels were reached more slowly and were lower than when ethinyl estradiol was given. In contrast to natural estrogens ethinyl, estrogens are bound to plasma proteins chiefly by nonspecific binding and are therefore less likely to affect the metabolism of the ethinyl estrogens than are the endogenous steroids. Also, significant amounts of ethinyl estradiol are was given. In contrast to natural estrogens ethinyl, estrogens are bound di-ethynylated in vitro. The pharmacokinetics of ethinyl estrogens differ from those of natural estrogens. This complicates interpretation of plasma or urinary estrone and estradiol measurements.

Clinical effects of ethynyl estrogens, used with and without progestational agents, on bleeding patterns, weight, and blood pressure.

PIP: 184 normal volunteers were treated with estrogen (ethynyl estradiol at .05 or .08 mg./day, or mestranol at .05, .08, or 0.1 mg/day) for 6 consecutive cycles. 1677 treatment cycles were accumulated and compared with 342 cycles from a group of 30 IUD users. There were significant differences in cycle regularity (onset of withdrawal bleeding or amenorrhea) between the 2 estrogens, the differences being dose-dependent and changing with successive cycles. The difference was attributed mainly to the frequency of amenorrhea, which was disproportionately high in the early mestranol cycles. Duration of withdrawal bleeding was greater with earlier mestranol cycles. Concomitant administration of a progestin markedly reduced the differences. Variability of cycle lengths was consistently less with mestranol combinations. One estrogen was not consistently better over the other. Cyclic estrogen therapy at any dose did not significantly affect body weight (over a 6-month period) nor systolic and diastolic blood pressure.^ieng

Comparative studies of the ethynyl estrogens used in oral contraceptives. I. Endometrial response.

Reproductive-age women were given identically prepared mestranol or ethynylestradiol orally for two consecutive 21 day cycles in doses ranging from 50 to 100 mug per day. Endometrial biopsies were obtained at the end of the second cycle and assessed for estrogenic effect. At these dose levels and with this treatment regimen, no differences could be detected between doses or between drugs, indicating that a plateau in endometrial response was reached.

PIP: The effect of 50-100 mcg of mestranol or ethinyl estradiol (EE) on the endometrium was studied in normal women who had never used oral contraceptives. Endometrial biopsies were obtained at the end of the 2nd cycle and assessed for estrogenic effect. Women using the low EE dose also used an IUD for contraception. Also, biopsies were obtained from women using IUDs alone. No histologic differences were found between different doses of the same drug (50, 80, 100 mcg mestranol; 50, 80 mcg EE). No histologic differences could be found between equal doses of mestranol and EE. The treated IUD users showed a delayed maturation of the secretory endometrium and an increased tendency towards predecidualization. The findings suggest that an endometrial plateau is reached with the 50 mcg dose, and that the tissue is relatively insensitive to increased dosage.

Comparative studies of the ethynyl estrogens used in oral contraceptives. II. Antiovulatory potency.

The occurrence or inhibition or ovulation was inferred from the plasma progestin level measured in the last week of 430 control cycles and of 4,638 cycles from fertile women receiving various antiovulatory steroids, singly and in combination. The substances tested included: mestranol and ethynylestradiol (EE) of homogeneous bioavailability, used alone in a range from 50 to 100 mug per day; these same dose levels combined with various progestins; and finally various proprietary combination and sequential low-dose regimens undergoing clincial trials. Statistical analysis showed ethynylestradiol and mestranol alone to be equipotent over the tested range, although at 50 mug per day superiority of mestranol over EE was suggested. Two preparations of EE at 50 mug per day, one of them a sequential with dimethisterone, showed different potency. At 50 mug per day no estrogen, alone or with a sequential progestin, reached a satisfactory level of effectiveness. However, very small amount in the range of 20 to 40 mug per day were highly effective when combined with quantities of various 19-nor progestins which by themselves are well below the antiovulatory level. This indicated that a synergism exists between these two classes of compounds insofar as their antiovulatory effect is concerned, thus explaining the high contraceptive effectiveness observed with very-low-dose combination regimens.

Comparative studies of the ethynyl estrogens used in oral contraceptives. III. Effect on plasma gonadotropins.

Twenty-one-day treatment cycles of ethynylestradiol or mestranol at dosages of 50 to 100 mug per day were administered to 191 normal volunteer women from six cycles, followed by six cycles of this estrogen treatment combined with 2.5 mg. of norethindrone acetate, 2 mg. of megestrol acetate, or 0.5 mg. of norgestrel. The drugs were prepared to insure uniform bioavailabiltiy. Plasma FSH and LH were determined by radioimmunoasay during the last week of medication intake in each cycle. In another study, a large number of blood samples were obtained at various times during the menstrual cycle from women using IUD's (as a control population) and from women who had been taking oral contraceptives regularly for 5 to 12 years. With the various estrogen treatments, the median FSH level showed no change at any estrogen dose at the end of the first cycle. From the second cycle on, a stable, dose-related fall was obtained with the 80 or 100 mug per day doses. The addition of any of the three progestins caused a prompt, stable, further fall in FSH level. By contrast, the median LH level rose in the first cycle with all estrogen regimens, and then fell progressively in a dose-related fashion in cycles 2 to 6. The addition of a progestational agent also caused a further prompt and stable fall in LH during cycles 7 to 12. Except for a minimal indication of greater LH suppression by ethynylestradiol as compared to mestranol at 50 mug per day, all other indices and dosages showed ethynylestradiol and mestranol to be essentially equipoten under these experimental conditions. Long-term administration of oral contraceptives produced a comparable degree of gonadotropin suppression. There was a suggestion of slightly less FSH suppression with agents using 50 to 75 mug per day of estrogen than from those with 100 mug per day. Both in normal controls (IUD cycles) and in cycles under chronic treatment with oral contraceptives, pulses of both FSH and LH were seen with some frequency, at times distant from the "periovulatory" period. The significance and origin of these random FSH and LH pulses is unknown.

PIP: The effects of ethinyl estradiol (EE) or mestranol on plasma follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were studies in 191 normal women. The women received 50-100 mcg/day of the estrogens over 21-day cycles for 6 cycles, followed by the addition of 2.5 mg norethindrone acetate, 2 mg megestrol acetate, or .5 mg norgestrel to the estrogens for 6 more cycles. Women using an IUD (controls) and women who had been taking oral contraceptives regularly for 5-12 years were also studied. At the end of the 1st cycle, median FSH levels did not change with any dose of EE or mestranol. However, from the 2nd cycle on, a dose-related FSH decrease was observed with 80 or 100 mcg doses of the estrogens. The addition of any of the 3 progestins promptly resulted in a further, although steady, decline in FSH levels. An increase in LH levels was observed in the 1st cycle of treatment with estrogens, although levels progressively declined, according to dose, during Cycles 2-6. Initiation of the combined treatment caused a further decrease in LH during Cycles 7-12. EE and mestranol were similarily equipotent, although EE was slightly more effective in suppressing LH at the 50 mcg dose. A comparable degree of LH and FSH suppression was found in the oral contraceptive group, although formulations containing 50-75 mcg/day estrogen were not quite as effective in suppressing FSH as were formulations containing 100 mcg estrogen. Sporadic increases in LH and FSH were observed with some frequency in the IUD cycles and in cycles involving therapeutic doses of oral contraceptives. The origin and meaning of these randon pulses is unknown.

Differences in the quality of semen in outdoor workers during summer and winter.

BACKGROUND AND METHODS: In warm climates throughout the world, there is a deficit of births during the spring season. To determine whether this deficit might reflect a deleterious effect of heat on the male reproductive capacity during the previous summer, we obtained semen specimens in summer and winter from normal men who worked outdoors in the vicinity of San Antonio, Texas, and we performed automated semen analyses with an image-analysis system. RESULTS: Pairwise comparisons among 131 men without azoospermia who contributed specimens in both summer and winter revealed significant reductions during the summer in sperm concentration, total sperm count per ejaculate, and concentration of motile sperm. The mean decreases in these values after adjustment for potential confounding characteristics were 32 percent (95 percent confidence limits, 28 and 44 percent), 24 percent (95 percent confidence limits, 18 and 43 percent), and 28 percent (95 percent confidence limits, 24 and 44 percent), respectively (P less than 0.0001). The lower a subject's average sperm concentration and motile-sperm concentration, the greater the reduction. We found no correlation, however, between the number of hours per day spent working during summer in settings without air conditioning and either the summer sperm concentration or the difference in concentration between summer and winter. Among the children of the men in the study whose wives were living near San Antonio during the year before they gave birth, a disproportionately low number were born during the spring. CONCLUSIONS: Semen quality deteriorates during the summer. This phenomenon may account at least in part for the reduction in the birth rate during the spring in regions with warm climates.

Evaluation of the clinical performance of three triphasic oral contraceptives: a multicenter, randomized comparative trial.

Three hundred thirteen women participated in an open, multicenter comparison of the incidence of intermenstrual bleeding (breakthrough bleeding and or spotting) associated with the use of three triphasic oral contraceptives. Triphasil (n = 107), containing levonorgestrel and ethinyl estradiol, and Ortho-Novum 7/7/7 (n = 97) and Tri-Norinyl (n = 109), both of which contain norethindrone and ethinyl estradiol, were administered over four cycles for a total of 1141 cycles. The total incidence of intermenstrual bleeding was significantly lower with Triphasil (17.2%) than with Ortho-Novum 7/7/7 (39.5%) or Tri-Norinyl (49.0%). The pattern remained the same when findings were analyzed cycle by cycle and for breakthrough bleeding and spotting separately. The incidence of other side effects was comparable for all regimens. Results of this study demonstrate superior cycle control with Triphasil compared with Ortho-Novum 7/7/7 and Tri-Norinyl during the first four cycles of use.

PIP: 313 women participated in an open, multicenter comparison of the incidence of intermenstrual bleeding (breakthrough bleeding or spotting) associated with the use of 3 triphasic oral contraceptives. Triphasil (n=107), containing levonorgestrel and ethinyl estradiol, and Ortho-Novum 7/7/7 (n=97) and Tri-Norinyl (n=109), both of which contain norethindrone and ethinyl estradiol, were administered over 4 cycles for a total of 1141 cycles. The total incidence of intermenstrual bleeding was significantly lower with Triphasil (17.2%) than with Ortho-Novum 7/7/7 (39.5%) or Tri-Norinyl (49.0%). The pattern remained the same when findings were analyzed cycle by cycle and for breakthrough bleeding and spotting separately. The incidence of other side effects was comparable for all regimes. Results of this study demonstrate superior cycle control with Triphasil compared with Ortho-Novum 7/7/7 and Tri-Norinyl during the first 4 cycles of use.