16. A C T I O N S OF H O R M O N E S
633
the proliferation of the uterine epithelium in the presence of the stroma
but did not influence isolated cells at the periphery of the explant.
In the epididymis, male hormone induced a secretion within the explant
but did not in the ectopic epithelium.
A similar difference in behaviour was demonstrated more recently
by other workers. In mouse prostate glands grown without male sex
hormone the isolated epithelium at the periphery became greatly disorganized but, unlike that growing within the organ, failed to recover
after addition of testosterone (Franks and Barton, 1960). Cell cultures
of oestrogen-induced kidney tumours of Syrian hamsters, which
in vivo remained dependent on oestrogenic hormones, grew well in
medium without additional hormones; the same tumour explanted as
organ culture broke down without hormones and had to be maintained
by addition of stilboestrol to the medium (Algard, 1960).
This loss of hormone sensitivity, or dependence, by the isolated
epithelial cells may be due to a selection of hormone-independent
elements or to a selective adaption which enables them to survive
in a hormone-free environment. Another possibility is that the presence
of an intact stroma is necessary for the hormones to become effective.
It has been shown that growth, function and hormonal response of
vaginal epithelia depended on the healthy condition of the underlying
stroma (Lasnitzki, 1958) and in cultures where epidermis was grown in
contact with "foreign" connective tissue the latter determined the
type of differentiation of the over-lying epithelium (McLoughlin, 1960)
and its response to hormones (Moscona, 1960). These findings suggest
that the connective tissue has an important function in the mediation
of hormone action and may transmit hormonal stimuli to the epithelium
through changes in the cells or matrix or, as suggested by Coujard
(1943), via autonomic nerve endings of the stroma.
V I . I N F L U E N C E OF H O R M O N E S ON T H E D E V E L O P M E N T
A N D F U N C T I O N OF T H E M O U S E M A M M A R Y G L A N D
The dependence of the mammary gland on a variety of hormones
in vivo has been established by many workers. A combination of oestradiol and progesterone promoted the ductal as well as the lobulo-alveolar
development of the gland in intact mice but failed to do so in hypophysectomized animals (Selye, 1940; Trentin and Turner, 1948;
Elliot and Turner, 1953). These hormones are now considered to be
synergistic to the pituitary hormones (Nandi, 1958a). Selye (1954) and
Faulkin and DeOme (1958) showed that corticosteroids also promoted
the differentiation of the organ. Experiments by Ahren and Jacobson
633
the proliferation of the uterine epithelium in the presence of the stroma
but did not influence isolated cells at the periphery of the explant.
In the epididymis, male hormone induced a secretion within the explant
but did not in the ectopic epithelium.
A similar difference in behaviour was demonstrated more recently
by other workers. In mouse prostate glands grown without male sex
hormone the isolated epithelium at the periphery became greatly disorganized but, unlike that growing within the organ, failed to recover
after addition of testosterone (Franks and Barton, 1960). Cell cultures
of oestrogen-induced kidney tumours of Syrian hamsters, which
in vivo remained dependent on oestrogenic hormones, grew well in
medium without additional hormones; the same tumour explanted as
organ culture broke down without hormones and had to be maintained
by addition of stilboestrol to the medium (Algard, 1960).
This loss of hormone sensitivity, or dependence, by the isolated
epithelial cells may be due to a selection of hormone-independent
elements or to a selective adaption which enables them to survive
in a hormone-free environment. Another possibility is that the presence
of an intact stroma is necessary for the hormones to become effective.
It has been shown that growth, function and hormonal response of
vaginal epithelia depended on the healthy condition of the underlying
stroma (Lasnitzki, 1958) and in cultures where epidermis was grown in
contact with "foreign" connective tissue the latter determined the
type of differentiation of the over-lying epithelium (McLoughlin, 1960)
and its response to hormones (Moscona, 1960). These findings suggest
that the connective tissue has an important function in the mediation
of hormone action and may transmit hormonal stimuli to the epithelium
through changes in the cells or matrix or, as suggested by Coujard
(1943), via autonomic nerve endings of the stroma.
V I . I N F L U E N C E OF H O R M O N E S ON T H E D E V E L O P M E N T
A N D F U N C T I O N OF T H E M O U S E M A M M A R Y G L A N D
The dependence of the mammary gland on a variety of hormones
in vivo has been established by many workers. A combination of oestradiol and progesterone promoted the ductal as well as the lobulo-alveolar
development of the gland in intact mice but failed to do so in hypophysectomized animals (Selye, 1940; Trentin and Turner, 1948;
Elliot and Turner, 1953). These hormones are now considered to be
synergistic to the pituitary hormones (Nandi, 1958a). Selye (1954) and
Faulkin and DeOme (1958) showed that corticosteroids also promoted
the differentiation of the organ. Experiments by Ahren and Jacobson