Evaluation of the response to tamoxifen (TX) on the uterine cytosolic progesterone receptor (cPR) through the occupied form of the nuclear oestrogen receptor (o-Rn)

347 -RELATIVE AFFINITY OF VARIOUS PROGESTINS AND ANTIPROGESTINS TO A RABBIT MYOMETRIUM RECEPTOR; Boonkasemsanti, W,; Aedo, A.R.; Cekan, S.Z. Reproductive Endocrinology Research Unit, Karolinske Hospital; 10401 Stockholm; SWEDEN Relative affinity of several progestins and antiprogestins to a cytosolic receptor prepared from the myomet~ium of estrogenized immature female rabbits was investigated. The cytosol was incubated (0 C for 3 hi with a constant amount of H-promegestone f H-R5020) in the presence of various concentrations of non-radioactive R5020 as standard on the one hand, and several progestins ard antiprogestins on the other hand. After charcoal separation of the unbound components, the incubate was subjected to isoelectric focusing in slabs of polyscrylamide gel and the bound radioactivity in the receptor zone wss measured. Parallel line assay design was used to assess the relative affinity to the receptor. The affinity was expressed as the potency to displace 3H-R5020 from the receptor. The potency of RX)20 was taken as 100 %. The compounds studied and their displacement potencies were as follows: progesterone 37 %, norethisterone 53 %, levonorgestrel 42 46,dextronorgestrel0 %, medroxyprogesteroneacetate 33 %, antiprogestin compound RU486 28 X, N-monodemethyl RU486 32 % N-didemethyl RiJ4868 %, propargyl alcohol RU486 12 %. The degree of displacement potency may be related to the b&logical activity of a compound, but cannot predict whether it will behave as an agonist or antagonist.

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STUDY ON THE EFFECT OF ANTIPROGESTATIONAL AGENTS ON GOAT OVARIAN GRANULOSA CELL ESTRADIOL PRODUCTION IN VITRO: Kharbanda S.M., Band V., Murugesan, K., Verma, U. and Farooq, A. Dept. of Reproductive Biology, All India Institute of Medical Sciences, New Delhi - 170029, INDIA, The effect of synthetic antiprogestins on estradiol (E ) production was investigated in vitro using granulosa cells from ovaries i;fnon pregnant goats. The cells were isolated and cultured for 48 hours in a humidified 95% air 5% CO2 atmosphere at 37OC. The basal production of progesterone in granulosa cells was high (4.3 ng/ml) compared to E2 (2.9 ng/ml). The production of E2 was significantly stimulated (PC O.OOl> by FSH (700 ng/ml) and A (HO-7M). The normal as well as gonadotrophin induced prgduction of Er, was significantly stimulated (PLO.05 - P LO.OO1) when blO- M concentra-L tions of STS 557, RMI 14156 and isomer 201 of RNI 12936 were used, while the ;f"f"~~twoantiprogestins, R 2323 and 5fiDNE, were without any significant The production of E was in the order of RMI 14156 >isomer 201 of RMI 12936, STS 557, Control a*R 2323 *50(DNE. R 2323 (a 'pregnenl deriv.) and 50 probably are not affecting aromatase, whereas STS 557 and RMI 14156 (an testrent deriv.) and isomer 20'1 (an gandrostg deriv.) behaves differently. RMI 14156 is a &5-3 ketosteroid and might get further metabolised to a deriv. of estrogen under the influence of ~5- A4 steroid isomerase, which is present in the granulosa cells and migh be responsible for the increased estradiol synthesis, -349

EVALUATION OF ?ZHERESPONSE TO TAMOXIPEN (TX) ON TEE UTERINE CYTDSOLIC PROGESTERONE RECEPTOR (cPR1 TRUTH TEE oCCUPIEDFOFGiOF TEE ~~~O~~EN RECEPTOR to-Rd. E.Castellano, M.I.Gonziles-Quijano and B.N.Dzaz-Chico. Dspts.of Pharmacology and Physiology.Cole gio Universitario de Las Palmas. Apdo.550.Las Palmas de G.C. Canary Islands. SPAIN. i Effects of Tx(lmg/kg) on cPR of ovarisctomised (OVX) rats and estrogeniaed one week later, are described. All the animals were implanted with 17-boestradiol (E2) oil solution silastic capsules and separated in two groups..Capsules remained inside during the whole experimentation and animals were injected 48h after the implantation with oii (controls) or TX in one group (a). In group (bf capsules remained inside only 48h and were removed before the injection of oil or Tx.Wwere decapitatad 24 or 48h after the injections. The cPR were meaoured b ??+R5020exchange and DCC method. The total and unbound nuclear receptors were measured by $ -E2 exchange method and TE or TEDG buffers, respectively. The differences between them gave the o-Pn ones. cPR and o-Bn values were 87 fmol/mg prot. and 25 fmol/mg DNA raspectively in OVX rats. These concentrations increased to 441 fmol/mg p. and 521 fmol/mg DNA in group (a) controls at 96h. The TX in jection depleted the cPR level to 202 fmol/mg p. and increased the o-Rn value to 717 fmol/mg D 48h after its administration. In group (b) controls the cPR and O-&I levels were 240 fmol/mg p. and 837 fmol/mg DNA 24h after removing the capsules and they did'nt show differences in relation to non-estrogenized rats at 96h. The TX injection had a two-phase response on cPR level with a depletion (89 fmol/mg p.)and a increase (366 fmol/mg p) 24 and 48h after, respectively. At the same times the o-Rn levels were 832 and 2278 fmol/mg DNA. Results suggest that the cPR synthesis induced by E2 would be relationed with the O-&J level. while E-P.ncomplex remains in cell nucleus the TX would manifest its antagonist effect. TX agonist response seems to need a (o-P.n)strong accumulation perhaps as compensation for its smaller effectiveness than E2. i

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