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 characteristics was performed during active (summer) and hibernating (winter) periods in two Urodele species: Triturus carnifex and Triturus alpestris. The significant decrease of the haemopoietic cell proliferation during the hibernation was accompanied by some modifications both at erythrocyte and leucocyte level. This situation was primarily characterised by a hypofunctionality and ageing of these cells with the disappearance of immature elements from the circulation and cell loss by apoptotic mechanisms. The results indicate that the condition of low metabolism during the winter period in these Urodeles involved deep changes in the physiology of haemopoietic tissue and blood circulating cells.