Characterization of the "4 S-trypsin" form of the cytosoluble estradiol receptor of calf uterus in a nondenaturing system]

The characterisation of the "4 S-trypsin" form of the estradiol-receptor from calf uterus cytosol was carried out by polyacrylamide gel electrophoresis under non-denaturing conditions. In a multiphasic buffer system (upper buffer Tris-glycine pH25degrees C = 8,6, lower buffer Tris HCl pH25degrees C = 7,4), three radioactive estradiol peaks were observed. The first was free estradiol, the second estradiol initially complexed with a macromolecule and dissociated during electrophoresis, and the third the hormone-receptor complex. The sedimentation coefficient (4 S) of this complex was the same before and after electrophoresis. Its mean geometric radius is R = 2.53 + 0.08 nm and its molecular weight was estimated to be 55,000.     

Hypoxia and estrogen receptor profile influence the responsiveness of human breast cancer cells to estradiol and antiestrogens

Angiogenesis activation mediated by vascular endothelial growth factor (VEGF) is one of the factors that can cause antiestrogen treatment failure in estrogen receptor (ER)?positive breast cancer patients. Since VEGF synthesis is modulated not only by hypoxia but also by steroid hormones, we investigated the relationship between hypoxic and estrogenic/antiestrogenic stimuli in two human breast cancer cell lines expressing both ER6α and ERβ (MCF7) or only ERβ (MDA-MB231). In both cell lines, the VEGF level was significantly influenced by hypoxic conditions and in antiestrogen-responsive MCF7 cells, this effect was not counteracted by tamoxifen or ICI 182,780, thus providing an experimental explanation for the resistance to endocrine treatment observed in patients with ER-positive tumors. In MDA-MB231 cells, estradiol significantly reduced the VEGF level, suggesting that through the ERβ isoform it may function as a negative modulator of VEGF synthesis under hypoxia, and providing evidence for a complex interplay of the estrogen-dependent and hypoxia-dependent pathways.     

Cellular and subcellular localization of3H-diethylstilbestrol in the pituitary,oviduct and uterus of the female rat

Summary Female rats were injected with³H-diethylstilbestrol. The pituitaries, oviducts, and uteri were removed and processed for autoradiography. The nuclear uptake and retention in these tissues appeared similar to that seen after the injection of³H-estradiol except in the pars nervosa of the pituitary gland.This study was supported by US PHS Career Development Award No. NS00164 and PHS Grant No. NS21933.     

Affinity of 1,2-substituted oxytocin analogues to the uterus receptor: Free-Wilson and Hansch analysis.

The analysis of pA2 values for 1,2-substituted oxytocin analogues suggests a significant resonance effect of p-substituted groups in 2-tyrosine when the hormone binds to its uterus receptor, whereas the N-terminal amino group exerts less clearly characterized effects (participation of its lipophilicity and molecular volume can be assumed.     

Early effect of estradiol on ultrastructure of chromatin in the endometrium and hormone-dependent mammary tumors]

After in vivo and in vitro administration of aestradiol, the chromatin of lamb endometrium and of hormone-dependent 7,12-dimethylbenzanthracene Rat mammary tumors is rapidly transformed from a condensed into a diffuse chromatin. A stimulation of 3H leucine incorporation into protein was also observed. These modifications were specific for estrogen receptor ligands and for estrogen responsive tissues. In vitro tamoxifen induced pycnosis. These changes could be used to improve the prediction of hormone dependency of human breast and uterine cancers.     

Interaction of glucocorticosteroids with glucagon in the control of argininosuccinase activity in the fetal rat liver]

Exogenous glucagon, but not glucocorticosteroids cause a rise in argininosuccinase activity in the liver of 21.5 day old fetuses. When fetuses are deprived of glucocorticosteroids, glucagon is unable to promote the enzymic activity. This study indicates that glucocorticosteroids are required for the induction of the argininosuccinase activity by glucagon.     

Combined effects of testosterone and estradiol on the ventral lobe of the rat postate in organ culture]

After organ culture without hormone, the epithelial gland cells of Rat veantral prostate undergo atrophic changes, whereas the interstitial stroma components tend to increase. Estradiol (1-1,000 nM),added to the culture medium, is ineffective. On the contrary, testosterone (1-100 nM) maintains epithelial cells and prevents the increase of interstitial stroma. When estradiol (1-1,000 nM) is combined with a physiological concentration of testosterone (1-4 nM), the epithelial cells are well maintained, but the inhibitory action of testosterone on the stroma is counteracted so that the glandular epithelium and the interstitial stroma are both stimulated. However, when testosterone is used at supraphysiological (10-100 nM) concentrations, estradiol is completely ineffective and the structure of the prostate is identical to the one given by the androgen alone.     

Morphology of the intercapsular segment of the oviduct in the golden hamster with special reference to ovumtransit from ruptured follicles to the ampulla

Summary The intercapsular segment of the oviduct in the golden hamster is not a simple duct which has constant outer and inner diameters. After penetrating the bursa ovarica the ICS has a circular constriction and the corresponding oviductal lumen is narrowed.