Effects of Light and Dark Environment on Weight Changes in Normal and Hypophysectomized Frogs

Abstract

It is a well established fact that the pituitary gland of the frog plays an important role in the dilatation and constriction of the melanophores in dark and light environments. It was shown by one of us1, 2 that injections of extracts of the posterior lobe of the pituitary gland produce a marked increase in water uptake in frogs as well as dilatation of the melanophores. Subsequently we became interested in the problem as to whether or not environmental background had any effect on the rate of weight changes in frogs kept constantly in water. The solution of this problem we feel, would help to determine whether the weight increase in frogs, resulting from the injection of pituitrin, is actually related to dilatation of the melanophores or to a more specific skin permeability.Two sets of experiments were carried out. In the first, 3 different groups each containing 6 normal frogs, were removed from water, dried carefully with gauze, and then weighed accurately to 0.1 gm. They were then put back in water o...