Characterisation of non-activated and activated estrogen- and antiestrogen-receptor complexes by high performance ion exchange chromatography.

The ionic species of cytosol estrogen receptors from mature rat uteri have been compared by HPIEC on a SynChrom AX-1000 column when complexed with either [125I]iodoestradiol, [3H]estradiol or [3H]4-hydroxy tamoxifen. Three species of receptors (isoforms) each suppressible by excess competitor were fractionated at identical salt concentrations regardless of ligand employed. One species eluted in the column void volume (10 mM) and the others at congruent to 90 mM and congruent to 155 mM phosphate.

The actions of prostaglandins and their interactions with angiotensin II in the isolated perfused human placental cotyledon.

The prostaglandins PGE1, PGE2, PGD2, PGF2 alpha, U46619 and 6 beta-PGI1 were administered as bolus injections both separately and in combination with angiotensin II into the fetal circulation of isolated human placental cotyledons perfused in vitro. PGF2 alpha and PGD2 caused small dose-dependent increases in fetal perfusion pressure when compared with U46619 which acted as an extremely potent vasoconstrictor of the fetal-placental vasculature. PGE1 caused very small dose-dependent decreases in fetal perfusion pressure when injected on its own.

Uptake, transfer and metabolism of prostaglandin E2 in the isolated perfused human placental cotyledon.

(3H) PGE2 uptake and transfer in the isolated perfused human placental cotyledon was assessed by a single pass paired isotope dilution technique utilising (14C) sucrose as an extracellular marker. Metabolism of (3H) PGE2 was measured by analysing maternal and fetal effluents from perfused human placental cotyledons after bolus injection of (3H) PGE2 into either the maternal or fetal sides. Maximal uptake of (3H) PGE2 was greater on the maternal (81 +/- 8%) than the fetal sides (42 +/- 12%) and showed saturation with increasing concentrations of PGE2 only on the fetal side with an apparent Km of 12 +/- 4.

Activation of oestrogen receptor complexes: evidence for the distinct regulation of ligand and oligonucleotide binding sites.

The activation of the rat uterine oestrogen receptor has been measured in vitro by its binding to oligodeoxythymidylate cellulose (oligo(dT] and was found to be sensitive to the time and temperature of prior incubation of cytosol with oestradiol. The presence of 20 mM dithiothreitol promoted receptor activation and was partially inhibited by 10 mM molybdate; molybdate also inhibited the time- and temperature-dependent activation of receptor. The nucleotides GTP, ATP, ADP, CTP and UTP all promoted receptor activation; the effect of GTP was significantly greater than that of ATP.

Prostaglandin production and stimulation by angiotensin II in the isolated perfused human placental cotyledon.

Levels of prostaglandins E and F2 alpha, thromboxane B2, and 6-oxo-prostaglandin F1 alpha were measured by radioimmunoassay in the maternal and fetal effluents of isolated human placental cotyledons perfused in vitro. All prostaglandins measured were released in greater amounts by the maternal side than by the fetal side of the perfused cotyledon although there were no consistent concentration gradients between the two sides. The approximate rank order of prostaglandin release into the maternal side was thromboxane B2 greater than prostaglandin F2 alpha congruent to prostaglandin E congruent to 6-oxo-prostaglandin F1 alpha, and that into the fetal side was thromboxane B2 congruent to prostaglandin F2 alpha congruent to prostaglandin E congruent to 6-oxo-prostaglandin F1 alpha.

Further characterization of the second oestrogen-binding species of the rat granulosa cell.

Rat granulosa cell cytosol contains a second oestrogen-binding species (SOB) distinguished from the classical oestrogen receptor by its lower dissociation constant (approx. 45 nmol/l) and the ability to bind oestrogens, antioestrogens, androgens and progesterone but not diethylstilboestrol. The SOB and the oestrogen receptor can be further distinguished by their differential adsorption to spheroidal hydroxylapatite and Concanavalin A-Sepharose.

A novel oestrogen-binding species in rat granulosa cells.

The dissociation constants (Kd) and steroid specificities of oestrogen-binding species in rat granulosa cell cytosol and nuclei have been studied. Preliminary work, where diethylstilboestrol was employed as competitor in binding assays, identified the oestrogen receptor in whole ovarian tissue nuclei (Kd 0.35 +/- 0.

The effects of the components of the renin-angiotensin system on the isolated perfused human placental cotyledon.

Angiotensins I, II, and III, renin substrate, and des-Asp1-angiotensin I were injected as a bolus into either the maternal or fetal circulation of human placental cotyledons perfused in vitro. All drugs tested produced dose-related increments in fetal perfusion pressure when injected into the fetal circulation, with the order of potency being angiotensin I approximately equal to angiotensin II approximately equal to angiotensin III greater than or equal to des-Asp1-angiotensin I greater than or equal to renin substrate. The responses to all the drugs could be blocked by the competitive inhibitor of angiotensin II, (Sar1, Ala8)-angiotensin II, but only the actions of angiotensin I, renin substrate, and des-Asp1-angiotensin I could be blocked by angiotensin converting enzyme inhibitor.

Activated oestrogen receptors in breast cancer and response to endocrine therapy.

The status of oestrogen and progesterone receptors has been measured in 147 primary breast tumours. In addition to the measurement of cytoplasmic oestrogen receptors, the ability of these receptors to bind to oligo(dT)-cellulose has been assessed. This indicates the capability for activation of cytoplasmic receptors to a form able to bind in the nuclear compartment in vivo and thus be part of a functional receptor pathway.

Prostacyclin production by human placental cells in short-term culture.

Human placentae of varying gestational ages have been cultured in vitro with little variation in cell type and pattern of growth found. Cell types found are similar morphologically and histochemically to those previously described. The biological specificity of the cells in culture was also confirmed by human placental lactogen production.

Decreased prostacyclin production by placental cells in culture from pregnancies complicated by fetal growth retardation.

Production of prostacyclin (PGI2) in vitro by human placental cells from pregnancies complicated by fetal growth retardation was significantly reduced compared with that in placental cells from normal pregnancies of either matched gestation or at term. This appeared to be due to a reduction of synthesis of PGI2 rather than to any alteration in the rate of its enzymic metabolism. Addition of oestradiol and progesterone increased PGI2 production by cells from pregnancies with fetal growth retardation in a similar manner to that by cells from first trimester pregnancies, implying that the placental cells are not irreversibly damaged by ischaemia.

Peripheral plasma immunoreactive 6-oxo-prostaglandin F1 alpha and gynaecological tumours.

Peripheral plasma levels of immunoreactive 6-oxo-PGF1 alpha, the stable hydrolysis product of prostacyclin, were significantly higher in female patients with tumours of the genital tract than in normal controls. In the groups with malignant tumours, these high levels declined after operation and/or radiotherapy if the tumour responded to treatment. In patients who did not respond to treatment or with tumour recurrence, levels of plasma 6-oxo-PGF1 alpha remained high or even rose further.

The binding of rat uterine cytosol oestrogen receptors to oligodeoxythymidylate--cellulose. Its relationship to a stable form of receptor complex with separate ligand- and oligonucleotide-binding sites.

The interaction of rat uterine cytosol oestrogen-receptor complexes with the synthetic acceptor oligo(dT)--cellulose was studied. Differences in the stability of receptor complexes and their ability to bind to oligo(dT)--cellulose on storage at 4 degrees C or when exposed to increased temperatures indicated heterogeneity of steroid- and oligonucleotide-binding sites. Dilution, dialysis and (NH4)2SO4 precipitation increased the interaction of receptor complexes with oligo(dT)--cellulose (a step termed activation).

A comparison of the quantitative analysis of 6-oxo-PGF1 alpha in biological fluids by gas chromatography mass spectrometry and radioimmunoassay.

Two sensitive and selective quantitative methods for 6-oxo-PGF1 alpha, the stable hydrolysis product of prostacyclin are described and compared. Prostaglandins were extracted from biological fluids with organic solvents. Samples for gas chromatographic mass spectrometric analysis required additional thin-layer chromatographic separation prior to conversion to the O-methyloxime, methyl ester, tri-trimethylsilyl ether.

Alterations in progesterone receptors in the rat uterus bearing an intra-uterine device during the oestrous cycle and early pregnancy.

The binding characteristics, content and intracellular distribution of cytosolic and nuclear progesterone receptors have been investigated, using [3H]progesterone as ligand, in the rat uterus bearing a unilateral intra-uterine device (IUD) during the oestrous cycle and from days 3 to 6 of pregnancy. The dissociation constants of nuclear and cytosolic progesterone-receptor complexes for IUD-containing and control uterine horns were similar. Cytosolic receptor concentrations in the IUD-containing uterus were always lower but changed in a manner similar to the control during the periods studied.

Effect of an intra-uterine device on intracellular relationships of the uterine oestrogen receptor, particularly during pregnancy.

The presence of an intra-uterine device in the rat results in a lower nuclear concentration of the oestrogen receptor in the treated horn at pro-oestrus when it is compared with the contralateral control horn. This effect was also seen after the administration of hyperphysiological doses of oestradiol and when the horn was exposed in vitro to high concentrations of oestradiol. The cyclic changes during the oestrous cycle in the activity of the oestrogen-induced enzyme peroxidase were similar in the treated and control horns.