The effect of excess vitamin A on tail regeneration in the Rana Ridibunda frog larvae

الملخص EN

The effect of different concentrations of vitamin A palmitate (2.5, 5, 7.5 and 10 IU/ ml water) on tail regeneration in stages II, IV, VI, VIII, X and XII of Rana ridibunda larvae was investigated.

Stage VI was chosen for further treatment with higher concentrations of vitamin A palmitate to determine the lethal dose of excess vitamin A, which was found to be more than 12 IU vitamin A/ml water for 12 days.

The inhibitory effect of excess vitamin A on tail regeneration of all stages, was dose-dependent.

As the stage of development progresses, the inhibitory action of vitamin A on tail regeneration decreases.

The highest percentage of inhibition (84.2%) was recognized in stage II larvae treated with 10 IU vitamin A/ml water, while the lowest percentage (6.5%) was recognized in stage XII larvae that were treated with 2.5 IU vitamin A /ml water.

Morphologically, there was a clear difference between tail regenerates in control and treated larvae, where it appeared in the latter very short and with little pigmentation.