The effect of fetal decapitation on the testis and other endocrine organs in the pig

Pig fetuses were decapitated at 42 days postcoitum. At 74, 90, 110 and 113 days postcoitum, 13 decapitated males in total were collected in order to study the effect of deprivation of pituitary hormones on the development of the testis and of other endocrine organs as well as on testicular descent. Decapitation did not markedly interfere with fetal growth, but the weights of testes, adrenals and thyroids were significantly reduced. In the testis Leydig cell development was most affected. These cells were almost absent and in the few remaining cells hydroxysteroid-dehydrogenases were histochemically undetectable. Increase in weight and length of the seminiferous tubules was diminished, but the diameter was increased. Germ cell development was quantitatively undisturbed. Gubernacular development was functionally unaffected, testicular descent occurred normally. It is concluded that the development of Leydig cells, seminiferous tubules, adrenal and thyroid depends on pituitary hormones during the second half of fetal life while the process of testicular descent is independent of these hormones in this period.