Einflu� des Vitamin A auf die MNNG-induziert Cancerogenese im Dr�senmagen der Ratte

Abstract

Carcinomas of the glandular stomach were induced in 82 Wistar rats by means of MNNG 1. Part of the group also received high doses of Vitamin A. A consistently significant increase in depth of invasion, i. e. progression of the pathological tumor stage, was observed under the influence of Vitamin A. The frequency of tumor occurrence was not significantly altered. The labilizing effect of Vitamin A on cellular membrane systems is the probable mechanism of Vitamin A's tumor-promoting influence in our experiment: 1. By way of destruction oflysosomal membranes, enzymes, cancerogens, and viruses would be released, leading directly or indirectly to an alteration of the DNA. 2. Damage of cell membranes would lead to loss of the contact inhibition.