Ability of implants of polymer-entrapped antiprogesterone antiserum to absorb and deplete progesterone from serum of the pregnant rat

A highly specific antiprogesterone antiserum (APA) produced by immunization of sheep with an 11 alpha-hydroxyprogesterone hemisuccinate-thyroglobulin conjugate was purified, and the IgG fraction was entrapped within a polysiloxane matrix. The matrix immobilized APA but allowed penetration and binding of progesterone (P) to the APA. In this entrapped form APA implanted intraperitoneally in rats on the tenth day of pregnancy resulted in a decline in serum P from 50 to 12 ng/ml within 12 hours and to less than 2 ng/ml within 36 hours. Free serum P measured by equilibrium dialysis fell to less than 0.2 ng/ml at 36 hours. Concomitant with the decline in serum P was a rise in both serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) and eventual fetal resorption.

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.

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.