THE ROLE OF THE THYROID IN THE CONTROL OF THE SLOUGHING CYCLE IN THE TOKAY (GEKKO GECKO, LACERTILIA)

Abstract

SUMMARY: The effects of thyroidectomy, and administration of thyroxine on the skin-shedding periodicity of the normal intact, and the thyroidectomized lizard (Gekko gecko) have been studied. Thyroidectomy decreased the frequency of sloughing, whereas the injection of thyroxine into thyroidectomized (8 μg. every second day) and intact (4 μg./day) animals increased the frequency. Only the resting phase of the sloughing cycle was affected, while the proliferation-keratinization phase remained unaltered. The rôle of the thyroid in the control of sloughing is discussed.