616
ILSE L A S N I T Z K I
G. EFFECT OF A D R E N A L I N E ON N E U R O F I B R I L F O R M A T I O N
Geiger (1958) showed that addition of very low doses of adrenaline
(0*001-0-005 /xg/ml) to cultures of adult rabbit cerebral cortex provoked
the formation of neurofibrils in the neurones within 30-90 min after
application of the drug. Time-lapse photography of the living neurones
showed that the optical density of nucleolus and nuclei changed immediately after addition of the drug. Fibrils appeared in the nucleolar
region, often as beaded chains, and from there extended gradually
into nucleus, cytoplasm, dendrites and axon. Cytoplasmic granules
which normally surround the nuclear boundary became dispersed
and formed large aggregates throughout the cytoplasm and dendrites.
One or two days after addition of adrenaline, even if fibril formation
was still proceeding, nucleus and nucleolus assumed a normal appearance. It was interesting that Janus Green B, which normally causes
chromatolysis and degeneration of neurones within 24 h, did not
inhibit the fibril formation in cultures treated with adrenaline.
V . T H E E F F E C T S OF S E X H O R M O N E S
A. EFFECTS ON TISSUE A N D CELL C U L T U R E S
The results of early work on the effects of sex hormones on the growth
of cell cultures are inconsistent and often contradictory. Oestrogens
were found to inhibit the growth of chick-heart fibroblasts (Tageguti,
1937) and of dental pulp, bone marrow and spleen from rabbits
(Yagi, 1940), while Kubo (1938, 1939) reported that follicular hormones,
androgens and preparations of corpus luteum promoted the proliferation of chick iris epithelium at low doses and retarded it at high concentrations. V o n Haam and Cappel (1940) obtained a growth stimulation of
embryonic-mouse heart fibroblasts by "oestrin" at dilutions of I O
-7
and a growth inhibition at those of I O
- 5
, while testosterone and
"progestine" inhibited it at all concentrations. Bullough (1954a)
observed that culture of epidermis from mouse ear explanted from
animals in pro-oestrus, i.e. when the oestrogen level of the animal was
high, showed twice as many cell divisions as those derived from mice
in dioestrus.
Mollendorff (1942), working with rabbit fibroblasts, demonstrated
that both oestrogens and androgens can act as mitotic poisons. Diethylstilboestrol, oestradiol, oestrone, methyltestosterone and testosterone,
in descending order, caused a profound disturbance of the spindle
mechanism, with breakage and dislocation of chromosomes resulting
ILSE L A S N I T Z K I
G. EFFECT OF A D R E N A L I N E ON N E U R O F I B R I L F O R M A T I O N
Geiger (1958) showed that addition of very low doses of adrenaline
(0*001-0-005 /xg/ml) to cultures of adult rabbit cerebral cortex provoked
the formation of neurofibrils in the neurones within 30-90 min after
application of the drug. Time-lapse photography of the living neurones
showed that the optical density of nucleolus and nuclei changed immediately after addition of the drug. Fibrils appeared in the nucleolar
region, often as beaded chains, and from there extended gradually
into nucleus, cytoplasm, dendrites and axon. Cytoplasmic granules
which normally surround the nuclear boundary became dispersed
and formed large aggregates throughout the cytoplasm and dendrites.
One or two days after addition of adrenaline, even if fibril formation
was still proceeding, nucleus and nucleolus assumed a normal appearance. It was interesting that Janus Green B, which normally causes
chromatolysis and degeneration of neurones within 24 h, did not
inhibit the fibril formation in cultures treated with adrenaline.
V . T H E E F F E C T S OF S E X H O R M O N E S
A. EFFECTS ON TISSUE A N D CELL C U L T U R E S
The results of early work on the effects of sex hormones on the growth
of cell cultures are inconsistent and often contradictory. Oestrogens
were found to inhibit the growth of chick-heart fibroblasts (Tageguti,
1937) and of dental pulp, bone marrow and spleen from rabbits
(Yagi, 1940), while Kubo (1938, 1939) reported that follicular hormones,
androgens and preparations of corpus luteum promoted the proliferation of chick iris epithelium at low doses and retarded it at high concentrations. V o n Haam and Cappel (1940) obtained a growth stimulation of
embryonic-mouse heart fibroblasts by "oestrin" at dilutions of I O
-7
and a growth inhibition at those of I O
- 5
, while testosterone and
"progestine" inhibited it at all concentrations. Bullough (1954a)
observed that culture of epidermis from mouse ear explanted from
animals in pro-oestrus, i.e. when the oestrogen level of the animal was
high, showed twice as many cell divisions as those derived from mice
in dioestrus.
Mollendorff (1942), working with rabbit fibroblasts, demonstrated
that both oestrogens and androgens can act as mitotic poisons. Diethylstilboestrol, oestradiol, oestrone, methyltestosterone and testosterone,
in descending order, caused a profound disturbance of the spindle
mechanism, with breakage and dislocation of chromosomes resulting