GROWTH-FACTORS AND THEIR RECEPTORS IN THE ANTERIOR-CHAMBER - ABSENCE OF EPIDERMAL GROWTH-FACTOR AND TRANSFORMING GROWTH-FACTOR-ALPHA IN HUMAN AQUEOUS-HUMOR

The involvement of growth factors such as epidermal growth factor (EGF ) in regenerative processes of corneal endothelium and lens epithelium has recently been suggested. However, knowledge on the presence of gr owth factors in anterior chamber fluid (ACF) is still very restricted. Although we have previously shown that EGF is undetectable in the ACF of normal eyes undergoing cataract surgery even by the use of high-se nsitivity assays, this does not exclude the possible presence of other , EGF-like proteins in ACF such as transforming growth factor alpha (T GF-alpha). In the present study, we have hence determined in ACF sampl es of 70 human eyes the concentrations of both EGF and TGF-alpha. As a ssays served ELISA techniques and RIA. In none of all the samples inve stigated could detectable amounts of EGF, i.e. above 0.2 pg/ml (detect ion limit of the assay), be found, confirming earlier results. Interes tingly, however, also no TGF-alpha could be detected in ACF. If presen t at all, the level of any TGF-alpha concentration in ACF was hence be low the detection limit, i.e. less than 20 pg/ml. Based on the results of this study, it seems therefore that under physiological conditions there is no measurable presence of free EGF or TGF-alpha in human ACF . Existing receptors in the structures of the anterior segment must he nce have ample binding capacity which could explain the effect of exte rnally applied growth factors. The physiological and clinical importan ce of this result is briefly outlined.