Xenobiotics in vitro: the influence of L-cystine, pantothenat, and miliacin on metabolic and proliferative capacity of keratinocytes

Cutan Ocul Toxicol. 2006;25(1):13-22. doi: 10.1080/15569520500536584.


To investigate the effect of cell growth-stimulating agents on human epidermal keratinocytes, we exposed monolayers of normal human keratinocytes derived from foreskin to different concentrations of the amino acid L-cystine, the member of the vitamin B family D-pantothenat, the phytosterol miliacin, and a combination thereof in keratinocyte growth medium. As a test system for the metabolic capacity, we used the activity of mitochondrial deyhdrogenases as measured by XTT, and for the cell proliferation, we determined the BrdU-uptake. The additives, active ingredients of the hair growth drug PRIORIN, were added in the presence of fully supplemented keratinocyte growth medium or a deficient medium without L-cystine, L-methionine, L-histidin, D-pantothenat, epidermal growth factor, and bovine pituary gland extract. Deficient medium itself reduced the metabolic capacity of keratinocytes to 35% compared with keratinocytes in fully supplemented growth medium. In deficient medium cell, proliferation was not measurable. Increasing doses of L-cystine restored the reduced metabolic capacity from 46% (0.009 mg/L) to 54% (0.09 mg/L) and 92% (0.45 mg/L) in deficient medium. Addition of D-pantothenat (0.43 mg/L) enhanced the metabolic capacity to 150% only in fully supplemented growth medium, compared with untreated controls with growth medium. Miliacin (6 mg/mL) increased not only the metabolic capacity (162%) but also stimulated cell proliferation (215%) as measured by BrdU-uptake in growth medium. The combination of all three additives increased the metabolic capacity (245%) synergistically in growth medium. We were able to show effects of D-panthenol, L-lysine, and miliacin on proliferation and metabolic capacity of keratinocyte monocell culture, which was further increased by combination of the three substances. These basic results suggest a beneficial effect on keratinocyte growth and stimulation by products combining these substances (e.g., Priorin). Furthermore, this work emphasizes the suitability of keratinocyte monolayers for pharmacological testings.

MeSH terms

  • Bromodeoxyuridine / metabolism
  • Cell Culture Techniques
  • Cell Proliferation / drug effects*
  • Cells, Cultured
  • Child
  • Child, Preschool
  • Cystine / pharmacology*
  • Drug Synergism
  • Humans
  • Keratinocytes / cytology
  • Keratinocytes / drug effects*
  • Keratinocytes / metabolism
  • Pantothenic Acid / pharmacology*
  • Tetrazolium Salts / metabolism
  • Triterpenes / pharmacology*
  • Vitamin B Complex / pharmacology*
  • Xenobiotics / pharmacology


  • Tetrazolium Salts
  • Triterpenes
  • Xenobiotics
  • 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-((phenylamino)carbonyl)-2H-tetrazolium hydroxide
  • Vitamin B Complex
  • Pantothenic Acid
  • Cystine
  • miliacin
  • Bromodeoxyuridine