Transforming growth factor-alpha is a constant component of human tear fluid

Graefes Arch Clin Exp Ophthalmol. 1994 Sep;232(9):523-6. doi: 10.1007/BF00181994.


Growth factors are known as a family of polypeptides with powerful influences on angiogenesis, tumor growth and wound healing. Transforming growth factor-alpha (TGF-alpha) and epidermal growth factor (EGF) are structurally related peptides which bind to the same receptor, EGF-R, and also exert similar effects. EGF is a natural component of human tears, and ocular disease leads to decreased concentrations in tear fluid. Using a sensitive radioimmunoassay we investigated whether TGF-alpha is also to be considered a natural component of tear fluid and in which concentrations it occurs. All of 46 tear fluid samples from 24 volunteers contained TGF-alpha. The mean concentration was 161.4 pg TGF-alpha/ml (SD 11.6 pg). No statistically significant correlation was found between tear fluid flow and TGF-alpha concentration in the sample. However, the concentration of TGF-alpha in tear fluid decreased significantly with increasing total time of tear fluid collection (P = 0.002). TGF-alpha levels in samples collected from males (n = 16) appeared to be higher (mean 247.0 pg/ml, SD 15.3 pg/ml) than in those from females (n = 30; mean 180.0 pg/ml, SD 8.5 pg/ml; P = 0.05). No correlation was found between the age of the individuals and the concentration of TGF-alpha in their tear fluid. The findings show that TGF-alpha is, like EGF, a constant component of human tear fluid. The dependence of TGF-alpha concentration on tear fluid flow and the physiological importance of its presence for corneal integrity and ocular surface physiology, however, require further investigation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Eye Proteins / analysis
  • Female
  • Humans
  • Male
  • Middle Aged
  • Radioimmunoassay
  • Tears / chemistry*
  • Transforming Growth Factor alpha / analysis*


  • Eye Proteins
  • Transforming Growth Factor alpha
  • tear proteins