INCREASED APOPTOSIS OF ADULT-RAT LYMPHOCYTES AFTER SINGLE NEONATAL VITAMIN-A TREATMENT (HORMONAL IMPRINTING) - A FLOW CYTOMETRIC ANALYSTS

Newborn rats were treated with a single dose of vitamin A (retinol) an d apoptosis of peripheral lymphocytes was studied by flow cytometry in adult age. Vitamin A treatment (hormonal imprinting) caused a moderat e, however significant elevation in the number of apoptotic lymphocyte s after three months. Dexamethasone or Concanavalin-A alone did not in fluence apoptosis significantly. However, in the neonatally retinol tr eated rats dexamathasone significantly elevated the quantity of apopto tic lymphocytes related to the control or Concanavalin-A treated contr ol cells. The results call attention to the prolonged effect of hormon al imprinting in a new index and to the possible dangerous effects in human, neonatally treated with vitamin A. (C) 1997 Elsevier Science In c.