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.     

arrow encodes an LDL-receptor-related protein essential for Wingless signalling

The Wnt family of secreted molecules functions in cell-fate determination and morphogenesis during development in both vertebrates and invertebrates (reviewed in ref. 1). Drosophila Wingless is a founding member of this family, and many components of its signal transduction cascade have been identified, including the Frizzled class of receptor. But the mechanism by which the Wingless signal is received and transduced across the membrane is not completely understood. Here we describe a gene that is necessary for all Wingless signalling events in Drosophila. We show that arrow gene function is essential in cells receiving Wingless input and that it acts upstream of Dishevelled. arrow encodes a single-pass transmembrane protein, indicating that it may be part of a receptor complex with Frizzled class proteins. Arrow is a low-density lipoprotein (LDL)-receptor-related protein (LRP), strikingly homologous to murine and human LRP5 and LRP6. Thus, our data suggests a new and conserved function for this LRP subfamily in Wingless/Wnt signal reception.