Seasonal Patterns of Adrenomedullary Hormones and Glycemia in the Soft-Shelled Turtle Lissemys punctata punctata

The aim of the present study was to acertain the seasonal pattern of adrenomedullary hormones and of glycemia in Lissemys turtles. Both the norepinephrine and epinephrine concentrations as well as blood glucose levels varied seasonally which began to rise from February, became maximum during April–May (early summer), declined during June–September (late summer) and were extremely low subsequently (October–January). The seasonal adrenomedullary hormonal and glycemic cycles however do not coincide with the annual ovarian cycle, thereby indicating that the adrenomedullary and glycemic cycles are out of phase with the ovarian cycle in turtles. The possible mechanisms of seasonality of the adrenal medulla and glycemia are discussed.