EFFECT OF PROSTAGLANDINS ON THYMIDINE-H-3 UPTAKE INTO HUMAN EPIDERMAL-CELLS INVITRO

Prostaglandins A2, B1, E1, E2, F1.alpha. and F2.alpha. were added to cultures of human epidermal cells (keratinocytes) for 24 h at 37.degree. C, and the effects on 3H-thymidine uptake into DNA was measured. At 70 .mu.g/ml all prostaglandins tested except PGF2.alpha. inhibited the uptake of 3H-thymidine greater than 50%. At 35 .mu.g/ml, PGA2 and PGB1 were the only 2 prostaglandins to show significant inhibition, 96% and 51%, respectively. At 17.5 .mu.g/ml only PGA2 caused substantial inhibition, 68%. In order to determine if the PGA2 action was mediated by membrane receptors propranolol, phentolamine, metiamide and prostynoic acid were added in conjunction with PGA2. None of the above receptor antagonists reduced the PGA2-induced inhibition of 3H-thymidine uptake. The pre-incubation of human keratinocytes with prostaglandins for 24 h probably decreases 3H-thymidine incorporation in DNA. The precise mechanism of action is unknown at this time.