Effects of Vitamin A and Thyroxine on the Metamorphosis of Indian Tree Frog, Polypedates maculatus

The present study was carried out to investigate and examine the effects of vitamin-A and thyroxine on growth, development and regenerative processes of amputed tails in Polypedates maculatus. On exposure to different dosages of vitamin-A, prolonged metamorphosis, regeneration of the amputed tail with visible malformations like bending of tail, formation of bulbular mass and ectopic limb development due to homeotic transformations of tissues were observed. At the same time tadpoles reared in sub-lethal dosages of thyroxine showed enhanced metamorphic changes, disappearance of caudal fin, reduction in growth, abnormality in the development of limbs and loss of pigmentation. Simultaneous exposure of tadpoles to both vitamin-A and thyroxine induced abnormalities like delay in development of hind limbs, emergence of forelimbs, resorption of tail and reduced mortality in comparison to tadpoles of thyroxine group. This study reveals that vitamin-A and thyroxine are antagonistic in nature and on simultaneous exposure to both resulted in intermediate effects on life cycle of Polypedates maculatus.