[Seasonal variations in the blood testosterone and thyroxine levels in the hedgehob (Erinaceus europaceus L)].

In adult male European Hedgehogs, which were studied outdoors, the plasma levels of both testosterone and thyroxine exhibited a marked annual cycle with a minimum in autumn and a maximum during spring and summer. The winter resumption of the testicular activity started already during the phase of hibernation and was concomitant with an increase of the plasma thyroxine level. The plasma titers of the two hormones dropped down together in August. The correlation between both hormones was less close from May through July.