Some of the factors controlling growth and differentiation of the right gonad in female domestic fowl

Abstract

The presence of the normal left ovary inhibits the development of both the cortical and medullary components of the rudimentary right gonad in fowl. Physiological amounts of estradiol benzoate (1 μg/100 gm body weight) completely inhibited the development of medullary tissue in ovariectomized fowl (poulards) but did not inhibit cortical tissue to the same extent as in the intact pullet. An ovarian brei, containing no detectable sex steroids (i.e., amounts of estrogen and androgen capable of feminizing plumage or causing comb growth) significantly retarded the growth and differentiation of the right gonad in poulards. Hypophysectomy completely inhibited the development of the right gonad in poulards. Severe thyroid insufficiency, induced by propylthiouracil, significantly suppressed or retarded the growth of this rudimentary organ. The results of these and other experiments indicate that the avian ovary produces one or more specific substances which inhibit the development of the right gonad. Suppression of this gonadal tissue following hypophysectomy is probably due to the lack of several trophic hormones, rather than to the absence of specific gonadotropins.