302
L. G A L L I E N
It is known that in cattle, when there are twins of opposite sexes, the male
calf is normal at birth, but the female has intersexual features, and is
sterile. The gonads are atrophied, lacking a cortex; the uterus and Mullerian
ducts are more or less inhibited. However, the WolfEan ducts and seminal
vesicles persist in varying degrees of development. The external genitalia
are of the female type. These changes occur only when vascular connections
have been established between the two fetuses. This fact leads to the belief
that the androgenic hormone or hormones from the male fetus act on sexual
organogenesis in the female, especially since the testes differentiate very
early, well before the ovaries in the female.
Starting from this situation, two methods of research have been followed
in various species of mammals. The first method involved early castration
in the fetus, to analyze the effects of absence of fetal hormones. The destruction of the fetal gonads in the mouse by X-rays (Raynaud and Frilley, 1947),
and their removal at the nineteenth day of gestation in the rabbit (Jost,
1947) have demonstrated effectively that the testicular androgens play a
major role in the differentiation of the genital tract. Castrated fetuses,
whatever their genetic sex, are organized according to the female type that
corresponds to the neutral sex: persistance of Mullerian ducts, involution
of Wolffian ducts, female appearance of external genitalia. Later, culture
in vitro of the reproductive tract from very early stages in the rat (Jost and
Bergerard, 1949; Jost and Bozic, 1951; Price and Pannabecker, 1956,
1959), the mouse (Brewer, 1962), and an insectivore, Galemys pyrenaicus
(Peyre, 1961) have confirmed the fact that the ovaries do not play a determining role in the organization of the female, but that the persistance of
the Wolffian ducts and their derivatives is dependent upon androgenic
hormones from the testis.
The conditions for differentiation of the gonads have been analyzed
by the method of transplants and in culture by Mclntyre (1956, 1960),
Holyoke (1956), and Holyoke and Beber (1958).
In a second method of research, the steroid hormones of the adult have
been administered to the fetus. Only in the opossum (Didelphis virginiana)
has an effect been obtained on the fetal gonads. Burns (1955a,b, 1956) was
able to cause feminization of male gonads with estradiol.
In placental mammals, in the numerous species studied, male or female
steroid hormones do not affect the sexual differentiation of the gonads.
Furthermore, it appears that the freemartin effect has never been produced
by the use of androgens. In fact, the results obtained with male hormones
differ perceptibly from those seen in the case of the freemartin. The androgens of the adult are without effect on ovarian differentiation, the Mullerian
ducts persist, the Wolffian ducts are of the male type, as well as the external
genitalia. Jost et al. (1963), by early administration of androgens to the
pregnant cow, obtained the same kind of reaction described above for other
L. G A L L I E N
It is known that in cattle, when there are twins of opposite sexes, the male
calf is normal at birth, but the female has intersexual features, and is
sterile. The gonads are atrophied, lacking a cortex; the uterus and Mullerian
ducts are more or less inhibited. However, the WolfEan ducts and seminal
vesicles persist in varying degrees of development. The external genitalia
are of the female type. These changes occur only when vascular connections
have been established between the two fetuses. This fact leads to the belief
that the androgenic hormone or hormones from the male fetus act on sexual
organogenesis in the female, especially since the testes differentiate very
early, well before the ovaries in the female.
Starting from this situation, two methods of research have been followed
in various species of mammals. The first method involved early castration
in the fetus, to analyze the effects of absence of fetal hormones. The destruction of the fetal gonads in the mouse by X-rays (Raynaud and Frilley, 1947),
and their removal at the nineteenth day of gestation in the rabbit (Jost,
1947) have demonstrated effectively that the testicular androgens play a
major role in the differentiation of the genital tract. Castrated fetuses,
whatever their genetic sex, are organized according to the female type that
corresponds to the neutral sex: persistance of Mullerian ducts, involution
of Wolffian ducts, female appearance of external genitalia. Later, culture
in vitro of the reproductive tract from very early stages in the rat (Jost and
Bergerard, 1949; Jost and Bozic, 1951; Price and Pannabecker, 1956,
1959), the mouse (Brewer, 1962), and an insectivore, Galemys pyrenaicus
(Peyre, 1961) have confirmed the fact that the ovaries do not play a determining role in the organization of the female, but that the persistance of
the Wolffian ducts and their derivatives is dependent upon androgenic
hormones from the testis.
The conditions for differentiation of the gonads have been analyzed
by the method of transplants and in culture by Mclntyre (1956, 1960),
Holyoke (1956), and Holyoke and Beber (1958).
In a second method of research, the steroid hormones of the adult have
been administered to the fetus. Only in the opossum (Didelphis virginiana)
has an effect been obtained on the fetal gonads. Burns (1955a,b, 1956) was
able to cause feminization of male gonads with estradiol.
In placental mammals, in the numerous species studied, male or female
steroid hormones do not affect the sexual differentiation of the gonads.
Furthermore, it appears that the freemartin effect has never been produced
by the use of androgens. In fact, the results obtained with male hormones
differ perceptibly from those seen in the case of the freemartin. The androgens of the adult are without effect on ovarian differentiation, the Mullerian
ducts persist, the Wolffian ducts are of the male type, as well as the external
genitalia. Jost et al. (1963), by early administration of androgens to the
pregnant cow, obtained the same kind of reaction described above for other