
experiments on the contribution of somatotrophin to prenatal growth in the rat
hypophyseoprivus in a fetal rat induced by decapitating the fetus in utero
retards fetal growth.  this effect can be prevented by injected somatotrophin.
these observations substantially support the view that in the normal rat
shortly before birth the fetal somatotrophin from the developing hypophysis
governs in part the prenatal growth which occurs at that time.  although
complete hypophysectomy of a pregnant rat retards
the growth of fetuses, the manner
of its action is obscure.  in an individual litter, combined hypophysectomy
of the mother and hypophyseoprivus in a fetus retards fetal growth but not
to any greater extent than hypophysectomy of the mother without
hypophyseoprivus in the fetus.  in the intact fetus injections of somatotrophin
(armour) do not accelerate fetal growth, presumably because ample fetal
somatotrophin from the developing hypophysis is present.
