[Extrapineal melatonin in processes of accelerated and premature aging in rats].

In order to reveal the participation of extrapineal melatonin in ageing processes, Wistar rats were (a) exposed to small doses of gamma irradiation and (b) subjected to pinealectomy. It was showed that during a radiation-induced aging simulation occurs a manifest hypoplasia of MT-responder cells in the mucosa of the duodenum, and the number of mast cells is reduced by ten times. During pinealectomy the number of MT-positive enterochromaffin cells increases.