CHANGES OF HEMATOPOIETIC ACTIVITY AND CHARACTERISTICS OF CIRCULATING BLOOD-CELLS IN TRITURUS-CARNIFEX AND TRITURUS-ALPESTRIS DURING THE WINTER PERIOD

Morphocytochemical correlation between proliferation (BrdU uptake) of the haemopoietic liver subcapsular tissue and peripheral blood cell ch aracteristics was performed during active (summer) and hibernating (wi nter) periods in two Urodele species: Triturus carnifex and Triturus a lpestris. The significant decrease of the haemopoietic cell proliferat ion during the hibernation was accompanied by some modifications both at erythrocyte and leucocyte level. This situation was primarily chara cterised by a hypofunctionality and ageing of these cells with the dis appearance of immature elements from the circulation and cell loss by apoptotic mechanisms. The results indicate that the condition of low m etabolism during the winter period in these Urodeles involved deep cha nges in the physiology of haemopoietic tissue and blood circulating ce lls.