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The purpose of the study was to determine the quantitative characteristics of IGF-1 binding sites in lens cells and to investigate its ability to modulate cell growth, in particular by inducing integrin expression. Studies were carried out in bovine lens epithelial cells in culture. IGF-1 receptor binding parameters were measured from saturation experiments with 125I-IGF-1. Scatchard plot indicates one class of high affinity sites (Kd = 2.5 +/- 1.5 nM). In addition, we showed that this growth factor was synthesized and released by lens cells. The characteristics of the receptor sites are in accordance with the effects of the growth factor (e.g. stimulation of DNA synthesis) in the range of nM concentrations. Moreover, by incubating cells with IGF-1 (12 nM) for 40 hr we demonstrated that the expression of integrin, the fibronectin receptor, was activated (N = 885 +/- 169 x 10(3) sites/cell vs N = 453 +/- 105 x 10(3) sites/cell in control cultures) without modification of its affinity (Kd congruent to 16 x 10(-8) M). These new data emphasize the role of IGF-1 in the regulation of migration, proliferation and differentiation of mature lens cells.

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The cp coefficients of azoles and their benzo-derivatives have been determined by i.r. and n.m.r. spectroscopy, based on the study of the NH2 bands arising from 1 -p-aminophenylazoles.KAUFFMANN suggested that ' azoles containing more than one N atom bound by way of an N atom correspond to halogen and other good negative leaving groups.' In this work we have attempted to make quantitative comparison on this basis by determining the C T ~ coefficients of N-substituted azoles.Two examples of good correlation between spectroscopic properties and Hammett (r coefficients exist for the aniline series. In the first case,2 the physical property which is measured is the symmetrical or antisymmetrical stretching vibration of the NH2 group determined in carbon disulphide [equations (l)] ; the v,(NH~) == -1.92 + 28.470, (Y 0.979) vas(NH2) = -3.30 + 40.310, (r 0-968)} (l) second3 is the proton chemical shift of the NH, group in dimethyl sulphoxide (DMSO). Thus we have prepared a series of l-@-aminophenylazoles in order to study their i.r. and n.m.r. behaviour and to determine their oP coefficients by these two independent methods. 8(NH2)= 290.6 + 79.27~ (urn and op) (Y 0.997) (2) EXPERIMENTALThe fifteen compounds studied were prepared by reduction of the corresponding fi-nitrophenyl derivatives (Table 1) by the following procedure. A mixture of 1-pnitrophenylazole (0.01 mol), stannous chloride (10 g), and concentrated hydrochloric acid (1 2 g) was heated until a clear solution was obtained. A dilute sodium hydroxide solution was added (basic pH) and the 1-9-aminophenylazole was extracted either with chloroform or with ethyl acetate. Yields were ca. 90%.All n.m.r. spectra were recorded a t 31.5' on a Varian A60 spectrometer. Solutions in anhydrous CaH,]DMSO were 0-2-0.4~ (we were able to verify that in some cases, in this range of concentration, the NH, chemical shifts were independent of the concentration). Measurements are given in Hz a t 60 MHz and are accurate to &Om5 Hz.1.r. spectra were measured using 1 0 -3 ~ solutions in CCl, with a Perkin-Elmer 225 spectrometer equipped with 1 cm cells (scan width, 5 cm-l per cm of paper; scan speed, 30 s per cm-1). In contrast to literature data,a we found that CS, is not a suitable solvent because it reacts with anilines to yield dithiocarbamic acids; 4 for this reason experiments were carried out in CCl, in spite of possible amine-CC1, interactions.2 The vas(NH) and v,(NH) values were