A synthetic 18-norsteroid distinguishes between two neuroactive steroid binding sites on GABAA receptors.

In the absence of GABA, neuroactive steroids that enhance GABA-mediated currents modulate binding of [35S]t-butylbicyclophosphorothionate in a biphasic manner, with enhancement of binding at low concentrations (site NS1) and inhibition at higher concentrations (site NS2). In the current study, compound (3alpha,5beta,17beta)-3-hydroxy-18-norandrostane-17-carbonitrile (3alpha5beta-18-norACN), an 18-norsteroid, is shown to be a full agonist at site NS1 and a weak partial agonist at site NS2 in both rat brain membranes and heterologously expressed GABAA receptors. 3alpha5beta-18-norACN also inhibits the action of a full neurosteroid agonist, (3alpha,5alpha,17beta)-3-hydroxy-17-carbonitrile (3alpha5alphaACN), at site NS2. Structure-activity studies demonstrate that absence of the C18 methyl group and the 5beta-reduced configuration both contribute to the weak agonist effect at the NS2 site. Electrophysiological studies using heterologously expressed GABAA receptors show that 3alpha5beta-18-norACN potently and efficaciously potentiates the GABA currents elicited by low concentrations of GABA but that it has low efficacy as a direct activator of GABAA receptors. 3alpha5beta-18-norACN also inhibits direct activation of GABAA receptors by 3alpha5alphaACN. 3alpha5beta-18-norACN also produces loss of righting reflex in tadpoles and mice, indicating that action at NS1 is sufficient to mediate the sedative effects of neurosteroids. These data provide insight into the pharmacophore required for neurosteroid efficacy at the NS2 site and may prove useful in the development of selective agonists and antagonists for neurosteroid sites on the GABAA receptor.

Synthesis of novel 13α-18-norandrostane-ferrocene conjugates via homogeneous catalytic methods and their investigation on TRPV1 receptor activation.

13α-Steroid-ferrocene derivatives were synthesized via two reaction pathways starting from an unnatural 16-keto-18-nor-13α-steroid. The unnatural steroid was converted to ferrocene derivatives via copper-catalyzed azide-alkyne cycloaddition or palladium-catalyzed aminocarbonylation. 16-Azido- and 16-N-(prop-2-ynyl)-carboxamido-steroids were synthesized as starting materials for azide-alkyne cycloaddition with the appropriate ferrocene derivatives. Based on our earlier work, aminocarbonylation of 16-iodo-16-ene and 16-iodo-15-ene derivatives was studied with ferrocenylmethylamine. The new products were obtained in moderate to good yields and were characterized by (1)H and (13)C NMR, IR and MS. The solid state structure of the starting material 13α-18-norandrostan-16-one and two carboxamide products were determined by X-ray crystallography. Evidences were provided that the N-propargyl-carboxamide compound as well as its ferrocenylmethyltriazole derivative are able to decrease the activation of TRPV1 receptor on TRG neurons.

Pharmacokinetics and pharmacodynamics of anordrin (2 alpha, 17 alpha-diethynyl-A-nor-5 alpha-androstane-2 beta, 17 beta-diol diproprionate).

In order to determine the pharmacokinetics of anordrin a dose of 0.2 mg/kg of [3-14 C]anordrin was administered i.v. to 5 cynomolgus monkeys; the same monkeys received the same dose i.m. at a later date. An additional 3 monkeys received 1.0 mg/kg of [3-14C]anordrin i.m. After administration of the compound, the dipropionate esters of anordrin were rapidly hydrolyzed to the dihydroxy parent compound, anordiol. After i.v. administration, anordrin had a mean residence time (MRT) of 5.0 +/- 1.3 (SE) min. [14C]Anordiol formed from [14C]anordrin had an MRT of 139 +/- 27 (SE) min. The metabolic clearance rates (MCR) of anordrin and anordiol were 55 and 34 mL/min.kg, respectively. The apparent volume of distribution at steady state (Vss) for anordrin was 276 mL/kg, 7.5% of body weight of the animals; anordrol had a much larger Vss of 4460 mL/kg. The MRT of anordiol after i.m. administration of 1.0 mg/kg of [14C]anordrin was 26.3 days. An average of 44% of the dose appeared in urine regardless of the route of administration or dose. The MRT values of total radioactivity were the same when calculated from serum or urine after an i.v. dose, but after i.m. administration, values from urine were approximately 60% of that calculated from serum, indicating that products appearing in urine had a shorter MRT than products appearing primarily in feces. A separate group of monkeys was given anordrin i.m. in doses ranging from 0.1 to 0.4 mg/kg on the first day of menses. The regression of length of menstrual cycle on dose was significant (P = 0.004).(ABSTRACT TRUNCATED AT 250 WORDS)

Antiestrogenic and antifertility actions of Anordrin (2 alpha, 17 alpha-diethynyl-A-nor-5 alpha-androstane-2 beta, 17 beta-diol 2,17-dipropionate).

Anordrin, administered in a single s.c. dose of 62.5 micrograms in sesame oil, stimulated sustained uterine growth (wet weight) when measured at 24 and 72 hr, but total soluble protein and total DNA per uterus was not increased. By comparison, 3 micrograms of estradiol-17 beta under the same conditions significantly increased all three parameters of uterine growth. Both of the above steroid treatments significantly increased nuclear estrogen receptor content of the uterus, but only the estradiol-17 beta treatment resulted in significantly elevated cytosol receptor content per uterus. Anordrin binds to the 8S estrogen receptor with an affinity of about 2 x 10(5) M-1 as determined by competition with [3H]estradiol-17 beta. The abortifacient activity of Anordrin when given orally (8 mg/kg b.w.) to mice on the 7th day of pregnancy was almost completely blocked by simultaneous oral administration of estradiol-17 beta (0.8 mg/kg b.w.). It is concluded that the actions of Anordrin on the uterus can be attributed to its antiestrogenic activities.

Antagonism of the actions of estrogens, androgens and progesterone by anordrin (2 alpha, 17 alpha-diethynyl-A-nor-5 alpha-androstane-2 beta, 17 beta-diol dipropionate).

Anordrin, an antifertility agent that is an antiestrogen with weak estrogenic activity, has been studied to further characterize its hormonal activities. A dose of 2.0 micrograms/mouse X day for 7 days did not increase the uterine content of protein, but it did inhibit to a small extent the effect of administered estradiol-17 beta on uterine protein content and more significantly the effect of estradiol-17 beta on the uterine content of progesterone receptors. Anordrin also decreased serum corticosteroid-binding globulin levels. Administration of an average daily dose of 160 micrograms/day of anordrin to intact male mice had no effect on weights of kidney, testis, or seminal vesicle after 10 days, but seminal vesicle weight was significantly decreased after 30 days at a slightly lower dose. Similarly, anordrin inhibited the increase in seminal vesicle weight induced by testosterone propionate treatment of castrated mice. In female mice anordrin failed to maintain deciduomata and blocked the ability of progesterone (2.0 mg/mouse X day) to do so. However, anordrin did not compete with the androgen [3H]R1881 for binding in kidney cytosol or with the progestin [3H]R5020 for uterine receptor sites. Anordrin also did not compete with [3H]corticosterone for binding to serum proteins.

Chemical synthesis and bioassay of anordrin and dinordrin I and II.

The chemical synthesis of 2 alpha, 17 alpha-diethynyl-A-nor-5 alpha-androstane-2 beta, 17 beta-diol dipropionate (Anordrin) and the corresponding diacetate is reported. Similarly, the preparation of the 2 alpha, 17 alpha-diethynyl-A-nor-5 alpha-estrane-2 beta, 17 beta-diol, its diacetate and dipropionate (Dinordrin I), along with the corresponding 2 beta-epimer (Dinordrin II) from 17 beta-hydroxy-A-nor-5 alpha=estran-2-one is described. In rat uterotrophic activity bioassay, the slope of ethynylestradiol differed significantly from the slopes of the other three compounds, thus vitiating potency estimates with this reference compound. Dinordrin I was 20 times more potent than Anordrin and considerably more potent then Dinordrin II. The single-dose oral antifertility effect in rats generally paralleled uterotrophic activity. Immediate postovulatory contraceptive effectiveness was assessed in adult cycling female baboons given two doses daily for 4 days. Both Anordrin and Dinordrin I showed antifertility activity worthy of further study. Moreover, a definite luteolytic effect, with depression of both plasma estrogen and progesterone levels, was observed with these two steroids.

Effect of Anordrin on serum levels of sex hormone binding globulin, caeruloplasmin and ovarian function.

Ten doses of 7.5 mg Anordrin were administered on alternate days from day 5 of the menstrual cycle to 20 women. Serum concentrations of both SHBG and CP were significantly increased after the fourth dose but the increases were minor compared to those produced by ethynyloestradiol. Two weeks after stopping Anordrin, serum concentrations of the proteins were still elevated in most women. Ovarian activity was studied in 8 women; serum oestradiol and progesterone concentrations indicated that ovulation occurred at the normal time in three women but was delayed for two weeks or more in the remaining five. The findings suggest that in humans, Anordrin acts as a weak oestrogen and may also have antioestrogenic activity.

Effects of anordrin and its analogue on antifertility.

Anordrin has been used as an effective postcoital contraceptive in China. The mechanism of anordrin and its analogue SIPPR-113 on antifertility has been studied. Anordrin and SIPPR-113 possessed estrogenicities and induced decrease in serum progesterone levels in rats. Their antiprogesterone activities might be mainly caused by their estrogenicities, which were the main but not the only contributors for the antifertility. The direct effects of anordrin and SIPPR-113 on human trophoblast cells were studied. A concentration of 50 micrograms/ml or 100 micrograms/ml of anordrin or SIPPR-113 could injure the human trophoblast cells in vitro. The uterine Pontamine blue reaction of mated rats was inhibited in those treated with anordrin or SIPPR-113 at the dose of 4 mg/kg. Anordrin, SIPPR-113 or AF-45 was given orally, intramuscularly and intravenously. The effects of drugs administered via the three routes were nearly the same. This study further demonstrated that anordrin was hydrolyzed to break its bond of dipropionate and was transformed into its parent steroid AF-45 to exert its antifertility effects in vivo. This study warrants that anordrin should been evaluated further.

Postcoital use of anordrin and RU 486 for prevention of implantation in the rat.

Because RU 486 synergizes with anordrin and its dihydroxylated metabolite to terminate established pregnancy in the rat and rabbit, the interactions of these agents were studied at two days postcoitally in the rat. RU 486 at a dose of 4 mg/kg did not prevent pregnancy when the animals were killed 12 days post insemination. A 2.5 mg/kg dose of anordrin prevented pregnancy in 14% of animals. By contrast, none of the animals became pregnant when treated with 2.5 mg/kg of anordiol. A non-effective dose of RU 486 (2 or 4 mg/kg) combined with a non-effective dose of anordrin (1.25 or 2.5 mg/kg) prevented pregnancy in all animals treated; there was no evidence of implantation sites or embryos when the animals were killed on day 12 post insemination. The same synergistic effect was observed when a small dose of RU 486 (e.g., 1 mg/kg) was combined with 0.6 mg/kg anordiol. To investigate the mechanism of pregnancy prevention, animals were treated two days postcoitally with 4 mg/kg of RU 486 plus 2.5 mg/kg of anordrin or 2 mg/kg of RU 486 plus 0.6 mg/kg of anordiol and were killed short intervals after treatment. These drugs had no effect by 6 h, but the numbers of embryos in oviducts were significantly reduced 12 h after treatment. By 24 h following treatment, no embryos were recovered from either the oviduct or the uterus. Progesterone and estradiol levels in serum collected 24 h after treatment were not significantly different from those of controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Anordiol and RU486 synergize to produce preimplantation pregnancy loss by increasing embryo transport (rat).

RU486, an antiprogestational agent, and anordiol (dihydroxylated metabolite of anordrin) which has an estrogenic and antiestrogenic activity, are known to inhibit fertility. These agents were administered orally, alone or together, to rats prior to implantation, on Day 2 of pregnancy. Control animals were fed with the vehicle only. The effectiveness of the agents in terminating pregnancy in female rats was determined on Day 14 of pregnancy. Anordiol presented a dose-dependent effect on abolishing pregnancy, being 100% effective at 2.5 mg/Kg and non-effective at 0.6 mg/Kg. RU486 did not prevent pregnancy even at a dose of 4 mg/Kg. Doses of RU486 and anordiol that were ineffective when administered alone, prevented pregnancy in 70% of the rats when these agents were given together. To determine the mechanism by which these drugs prevent pregnancy, oviducts and uteri of rats were examined for presence of embryos on Day 3 of pregnancy. Only 29% of embryos were recovered from the oviducts of rats treated with 2.5 mg/Kg anordiol (compared to 89% in control group) plus an additional 9% from the uteri. In combination, anordiol and RU486 had a synergistic effect on embryo transport in the rats' reproductive tract, without any apparent accumulation in the uterus. These results led us to conclude that the pregnancy preventing action of anordiol plus RU486 is mostly due to accelerated transport of the embryos in the reproductive tract prior to implantation.

Anordiol produces pregnancy loss in the rat--via the embryo or via the uterus?

Anordiol, the dihydroxylated metabolite of anordrin, is an antiestrogen with estrogenic activity that is known to inhibit fertility. The following study was conducted to determine the mechanism of this antifertility effect. Anordiol was administered orally to rats, prior to implantation, on Day 2 of pregnancy. Control animals were treated with the vehicle only. The effectiveness of the agent in terminating pregnancy was determined on Day 14 of pregnancy. Anordiol was 100% effective in abolishing pregnancy at a dose of 0.6 mg/Kg. Administration of smaller doses resulted in a decreased number of implanting embryos, in a dose-dependent manner. An additional dose of anordiol on Day 3 of pregnancy yielded similar results. To determine whether pregnancy impairment by anordiol is exerted via the embryo or via the uterus, reciprocal embryo transfers were performed. Day 5 blastocysts were transferred into the uteri of pseudopregnant rats. In one set of experiments, the donor rats were treated with anordiol, and in the second set the recipient rats were treated. The results indicate that the effects of anordiol administration are exerted via the embryo as well as the uterus.

Comparative effectiveness of three antiprogestins alone and in combination with anordiol in terminating pregnancy in the rat.

The effectiveness of mifepristone, onapristone, and ORG 31806 alone or in combination with anordiol to terminate pregnancy in the rat was evaluated. ORG 31806 at a dose of 2 mg/kg/day, mifepristone at 4 mg/kg/day, and onapristone at 8 mg/kg/day, terminated pregnancy in all treated animals. Anordiol, an antiestrogen, at a dose of 5 mg/kg/day, terminated pregnancy in all treated animals. Anordiol acted synergistically with all three antiprogestins terminating pregnancy in the rat. The antiprogestins at doses that were either partially effective or non-effective became 100% effective when administered with a non-effective dose of anordiol. Thus, combination of ORG 31806 (1 mg/kg/day) plus anordiol (0.31 mg/kg/ day), mifepristone (1 mg/kg/day) plus anordiol (0.62 mg/ kg/day), and onapristone (2 mg/kg/day) plus anordiol (2.5 mg/kg/day) terminated pregnancy in all treated animals. These combinations of the antiprogestins and anordiol decreased significantly the serum progesterone levels but not serum 17 beta-estradiol levels. The present results indicate that the most potent combination was ORG 31806 plus anordiol.

PIP: The pregnancy termination potency of varying doses of mifepristone, onapristone, and ORG 3806--alone and in combination with the estrogenic/antiestrogenic compound anordiol--was evaluated in adult rats. The antiprogestins and anordiol alone were administered to pregnant female rats on days 7, 8, and 9 of pregnancy and the presence or absence of embryos in utero was determined on day 16. ORG 31806 at a dose of 2 mg/kg/day, mifepristone at 4 mg/kg/day, and onapristone at 8 mg/kg/day terminated pregnancy in 100% of animals; 5 mg/kg/day of anordiol was required. Anordiol acted synergistically with all three antiprogestins. Antiprogestin doses that were either partially effective or ineffective became 100% effective when administered with a noneffective dose of anordiol. The combination of ORG 31806 (1 mg/kg/day) and anordiol (0.31 mg/kg/day) had the most potent pregnancy termination activity. The administration of antiprogestins in combination with anordiol at doses that effectively terminate pregnancy was associated with a significant, persistent reduction in serum progesterone, but no change in serum estradiol levels. The effectiveness of ORG 31806 and anordiol in terminating pregnancy should be evaluated in a non-human primate model to determine its potential clinical use.

Additive effect of RU 486 and anordrin on pregnancy interruption in the mouse.

The effect of various doses of anordrin and RU 486, alone or combined, on serum progesterone (P) levels, fetal resorption, and recovery of ovulation was studied in mice. Each drug was given as a single sc injection on day 7 of pregnancy and autopsy was performed on days 8, 9, or 11. Serum P was normal at 24 h but fell significantly 48 h after treatment with anordrin (0.05 mg). Doses of 0.05 or 0.2 mg anordrin were effective in interrupting pregnancy in 30% and 70% of pregnant mice, respectively. RU 486, 0.01 mg per mouse, induced a pronounced decrease of P levels 24 h after treatment and interrupted pregnancy in 50% of pregnant mice. The combined treatment with submaximal doses of anordrin plus RU 486 did not further decrease P levels, but increased the proportion of mice with fetal resorptions to 90%. The combination of small doses of anordrin with RU 486 had an additive effect on pregnancy termination. The additive effect required a dose of RU 486 above the threshold level. Direct observation of aborted fetuses indicated that the resorptive process occurred earlier with RU 486 than with anordrin. Recovery of ovulation was associated with pregnancy termination in a high proportion of mice treated with either drug or their combination.

Anti-uterotrophic and folliculostatic activities of anordiol (2 alpha,17 alpha-diethynyl-A-nor-5 alpha-androstane-2 beta,17 beta-diol).

The estrogenicity and antiestrogenicity of the biologically active metabolite of the contraceptive anordrin was investigated for its actions on both the uterus and ovary. Anordiol (30 micrograms), administered s.c. to ovariectomized mice did not significantly increase wet weight, soluble protein content, or DNA content of uteri 72 hours after a single dose. By comparison, 3 micrograms of estradiol-17 beta under the same conditions significantly increased all three parameters of uterine growth. The increments in uterine wet weight, soluble protein content, and DNA content that were induced by estradiol-17 beta were reduced by 50, 71, and 81%, respectively, when 30 micrograms of anordiol was administered with estradiol-17 beta. A 60 micrograms dose of anordiol did not decrease further any of the three parameters. In further evaluation of the uterine response to anordiol an increase in uterine wet weight and soluble protein was observed with both 30 and 90 micrograms doses of anordiol at 12, 24, 36, and 48 hours, but not at 6 or 72 hr after a single s.c. injection. No significant increase in uterine DNA content was observed with either dose at any time. We conclude that anordiol in this assay is an antiestrogen with weak estrogenic activity. Anordiol was further tested to determine its effect on the estrous cycle of the rat. When given on the afternoon of the first day of diestrus in a dose of 0.8 mg/kg body weight in rats with 5-day estrous cycles, it caused an average lengthening of the cycle to 9.1 +/- 2.1 (S.D.) days.(ABSTRACT TRUNCATED AT 250 WORDS)

Anordiol is more potent than anordrin for terminating pregnancy when administered with RU 486.

In view of the unexpected ability of anordrin to synergize with RU 486 in terminating pregnancy, it was pertinent to examine the actions of the dihydroxylated metabolite of anordrin, anordiol, alone and in combination with RU 486. Does of RU 486 (1 mg/kg/day) and anordiol (0.6 mg/kg/day) that were ineffective when given alone terminated pregnancy with complete resorption of embryos when administered together. A smaller dose of anordiol than anordrin is required to achieve this synergistic effect with RU 486. This anordrin metabolite increased uterine weight in the ovariectomized rat similar to estradiol. The estrogenicity of anordiol in the uterine weight assay was about 1/120 of that of estradiol. Anordiol does not exert antiestrogenic activity in the uterine weight assay when administered at doses that terminate pregnancy. Administration of anordiol at doses that do not terminate pregnancy resulted in a significant suppression of serum progesterone concentrations during the period of medication; these observations suggest that anordiol has an inhibitory effect on progesterone biosynthesis. When the same dose of anordiol was given concomitantly with sufficient RU 486 (e.g., 1 mg/kg/day) to terminate pregnancy, the progesterone levels were reduced to low levels throughout the experiment. These observations support the postulate that the actions of anordrin are mediated by its metabolite, anordiol. The administration of anordiol plus RU 486 results in a more dramatic change in the functional progesterone:estradiol ratio than when either agent is administered alone.

A-nor steroids as post-coital contraceptives in the hamster with special reference to the transport and degeneration of eggs.

Two A-nor steroids, Anordrin and H241, showed a marked antifertility effect when given orally to hamsters at 10 mg/kg/day for three or four days after mating. Further study indicated that the antifertility effect was due to a disturbance of egg transport, retarded development and degeneration of fertilized eggs.

Anti-implantation activity of antiestrogens and mifepristone.

To develop a better postcoital contraceptive, the following antiestrogens were tested for their anti-implantation activity in the rat: anordrin, anordiol, tamoxifen, ICI 182,780, and RU 39411. The compounds were administered orally or subcutaneously (s.c.) to female rats on days 1, 2, and 3 of pregnancy. All the antiestrogens tested were 100% effective in preventing blastocyst implantation. The lowest effective doses when administered orally were 10, 1.25, 0.062, 6.0 (partially effective), and 0.01 mg/kg/day, respectively. The estimated median effective doses (ED50) were 5.60, 0.40, 0.035, 5.40, and 0.0074 mg/kg/day, respectively. When administered s.c., the minimum effective doses in preventing blastocyst implantation in all animals were 2.0, 0.1, 0.1, 0.1, and 0.01 mg/kg/day, respectively. Anordrin, anordiol, and ICI 182,780 were more potent when administered s.c.; whereas tamoxifen and RU 39411 were effective at similar doses when administered parenterally or orally. RU 39411 was the most potent among the antiestrogens tested and should be evaluated as a potential postcoital contraceptive. The administration of mifepristone, an antiprogestin, at a dose of 8 mg/kg/day blocked blastocyst implantation in all treated animals; whereas at a dose of 4 mg/kg/day or lower, the drug was ineffective. These findings confirm that estradiol and progesterone are essential for blastocyst implantation in the rat. The capacity of mifepristone to potentiate the anti-implantation activity of the antiestrogens was also determined. The combination of a non-effective dose of each of the antiestrogens (anordrin, anordiol, and tamoxifen), and RU 39411, with mifepristone at a non-effective dose, prevented pregnancy, demonstration that an antiprogestin and antiestrogen act synergistically in blocking blastocyst implantation in the rat. The antiestrogen compounds whose anti-implantation activities were potentiated by mifepristone were found to possess significant estrogenic activity, when assayed by measuring the increase in the uterine weights of ovariectomized rats. The only exception was ICI 182,780, which showed no estrogenic activity in the uterine weight bioassay and did not act synergistically with mifepristone in blocking blastocyst implantation. Estradiol was effective in preventing pregnancy at a dose of 1 microgram/kg/day. The combination of non-effective doses of estradiol and mifepristone did not prevent pregnancy. The findings that mifepristone potentiates the anti-implantation activity suggests that the synergistic effect may be a unique property of this class of antiestrogens.

PIP: In New York, female and male rats copulated on the afternoon of proestrus as part of a study aiming to determine whether antiestrogens alone or in combination with mifepristone (RU-486) will block blastocyst implantation in the rat. This study is part of research efforts to develop a better postcoital contraceptive. The antiestrogens included RU39411; ICI 182,780; anordrin; anordiol; tamoxifen; and estradiol. The laboratory researchers treated the rats orally or subcutaneously on days 1, 2, and 3 of pregnancy. They killed them on day 8-9 to examine the uteri for the presence or absence of implanted embryos. All the antiestrogens effectively prevented blastocyte implantation. Using the measurement mg/kg/day, the lowest effective oral dose was 10 for anordrin; 1.25 for anordiol; 0.062 for tamoxifen; 6 (80% effective) for ICI 182,780; and 0.01 for RU 39411. These antiestrogens' estimated median effective doses were 5.6, 0.4, 0.035, 5.4, and 0.0074 mg/kg/day, respectively. In all animals, the minimum effective doses administered subcutaneously were 2, 0.1, 0.1, 0.1, and 0.01 mg/kg/day, respectively. Anordrin, anordiol, and ICI 182,780 were more effective during subcutaneous administration while tamoxifen and RU 39411 were as effective at similar doses during parenteral or oral administration. The most potent antiestrogen was RU 39411. This antiestrogen should be evaluated as a potential postcoital contraceptive. An 8 mg/kg/day dose of RU-486 blocked blastocyst implantation in all rats. The 4 mg/kg/day dose was completely ineffective. RU-486 augmented the activity of anordrin, anordiol, tamoxifen, and RU39411 synergistically, resulting in prevention of pregnancy at non-effective doses of RU-486 and the antiestrogens. These same antiestrogens also exhibited significant estrogenic activity as determined by an increase in uterine weights of ovariectomized rats. Estradiol prevented pregnancy at a dose of 1 mcg/kg/day. RU-486 did not potentiate estradiol. These findings suggest that the synergistic effect of anordrin, anordiol, tamoxifen, and RU39411 may be unique to these antiestrogens.

Estrogenic and antiestrogenic activities of anordiol: a comparison of uterine and vaginal responses with those of clomiphene citrate.

Anordiol (2 alpha,17 alpha-diethynyl-A-nor-5 alpha-androstane-2 beta,17 beta-diol) has been variously characterized as an estrogen and as an antiestrogen. To more completely understand the pharmacological properties of this contraceptive steroid, simultaneous responses were studied in uterine, vaginal, and hepatic tissues. Rats received 4 daily sc injections with either anordiol, clomiphene citrate (CC), or the vehicle alone (C+) starting on the first day of pseudopregnancy. Uteri were traumatized on day 4 of pseudopregnancy, and rats were sacrificed 5 days later. A pseudopregnant group without uterine trauma served as a negative control (C-). Mean uterine weights per animal and cytosolic estrogen (EcR) and progesterone (PcR) receptor activities per g of DNA were all 5- to 7-fold greater in the C+ group than in the other groups (all p < 0.05). However, anordiol and CC suppressed uterine weight without suppressing the stromal proliferative response; the DNA content of the uteri of anordiol- and CC-treated rats was similar to that of C+ rats. Vaginal tissue exhibited estrogenic responses to anordiol and CC with an increase in epithelial stratification compared to the C+ and C- groups even though no difference in levels of EcR/g of DNA were expressed 5 days after the last antiestrogen dose. Binding affinities and serum E2 and progesterone (P) concentrations were not statistically different among the groups. In conclusion, anordiol produced responses in the uterus and vagina of the pseudopregnant rat which were indistinguishable from those of CC, and, therefore, we conclude that anordiol acts on these tissues as an antiestrogen.

Plasma progesterone levels in normal and pregnant Chinese women and effects of contraceptives on them.

PIP: Progesterone concentrations in peripheral plasma were determined by competitive protein binding assay during normal human menstrual cycles and in pregnancy. In addition, to investigate the mode of action of anordrin (a postcoital pill) and AF-75 (an effective antifertility nonsteroid in animals) and to evaluate their clinical efficacy, the effects of these 2 chemicals on plasma progesterone levels were also studied. 33 women with normal menstrual cycle and fertility gave blood samples on various days before and after ovulation, according to basal body temperature changes. During the follicular phase, the plasma progesterone level was less than 1 ng/ml (mean .39). After ovulation, the progesterone levels rose gradually, reaching maximal values of 7-15 ng/ml 6-9 days before menstruation. Then the concentrations fell off gradually to below 2 ng/ml on the day before or on the first day of menses. 77 pregnant women at various stages of pregnancy gave blood samples. Plasma progesterone levels during early pregnancy were similar to those of luteal phase. The concentrations gradually rose to a peak in late pregnancy, with the maximal figure being over 130 ng/ml, although there were individual variations. 10 women of child-bearing age were given 7.5 mg of anordrin daily 1-5 days before ovulation, 5 times. Plasma progesterone levels on various days after ovulation were assayed and compared with untreated control cycles. Ovulation did occur in every medicated cycle, but the maximal progesterone values in luteal phase were lower than those of untreated cycles (P .01), and luteal periods were shortened (P .05). Administration of AF-75 showed no conspicuous effect on ovulation or development of corpus luteum in normal women.^ieng

[The absolute configurations and biological activities of alpha- and beta-anordrins].

The molecular structures and absolute configurations of alpha- and beta-anordrins are reported. Animal experiments showed that pure alpha-epimer possessed high anti-implantation and anti-early pregnancy effects, but the pure beta-epimer exhibited very low effects at the same dose. MNDO program was applied for the optimization of the configurations of epimers to establish the isolated molecular configurations and calculate the quantum chemical indexes. The results showed that the configurations and the differences of action field in three-dimensions of alpha- and beta-epimer are probably the factors that the alpha-epimer exhibited biological activity.