Lactogen Content of the Anterior Pituitary of Growing Rabbits and Guinea Pigs. ∗

Summary

While the lactogen content of the AP of the male rabbit is very low and almost constant during all phases of growth and adult life, that of the male guinea pig increases very rapidly at puberty and even exceeds the content of the mature non-lactating female. In the case of the females of both species, there is a marked rise in the lactogen content of the AP associated with increased ovarian weight at sexual maturity. In a comparison of species, on the basis of the lactogen per gram of AP, it was observed that the mature female guinea pig ranks first with about 600 B.U., the albino rat second with about 500 B.U., and the rabbit third with about 300 B.U.