The thyroid and the hypophysial gonadal axis in the female Spotted Munia, Uroloncha punctulata

Abstract

When adult female Spotted Munia (Uroloncha punctulata) are surgically thyroidectomized the diameter of the ovarian follicles and the weight of the body start incrasing, reach a maximum, and then hold a plateau. In the juveniles, while there is an early, though partial, but significant increase in the weight of the body and of the ovary, maximal development occurs only at the approach of the breeding season. Further, although the dark pigment and its deposition pattern on the feathers remain unaffected, in the absence of the thyroids feather growth is retarded and the development of the barbules is inhibited. It is suggested that the effects on the plumage are probably due to an indirect action of the thyroids by way of the body metabolism, but that those on the body weight and ovary are due to the direct influence on the hypothalamo/hypophysial/gonadal axis. © 1967.