16. A C T I O N S OF H O R M O N E S
593
I I . E F F E C T S OF I N S U L I N A N D G R O W T H H O R M O N E
A. EFFECTS ON TISSUE A N D CELL C U L T U R E S
It is now recognized that insulin not only stimulates carbohydrate
metabolism, but that it also plays an important part in protein synthesis. Thus insulin stimulates rapid growth and increases the retention
of nitrogen in hypophysectomized animals (Lawrence, Salter and Best,
1954).
Cells derived from various different animal species and grown in
culture in the presence of insulin showed an increase of growth. Gey
and Thalhimer (1924) observed a marked stimulation of cell proliferation in cultures growing in a medium to which insulin had been
added. V o n Haam and Cappel (1940), who grew mouse-embryoheart fibroblasts with doses of insulin ranging from 0*001 to 1 unit/ml
of medium, reported an increase of the mitotic index and of cell
multiplication which ranged from twice the control value at the
lower concentrations to 9-10 times at the higher doses. An interesting
finding was that the treated cells showed a rapid accumulation of fat
droplets in their cytoplasm, which became more extensive with rising
doses of the hormone.
Leslie and Davidson (1951), Leslie (1952) and Leslie, Fulton and
Sinclair (1957) investigated the effect of insulin (0-1-3 /x/ml) on fresh
explants of chick-embryo heart, on human embryonic skin fibroblasts
and kidney cells and on three strains of human tumour cells, HeLa,
Hep 1 and Hep 2. Insulin promoted cell proliferation and increased
the total amount of lipid phosphorus (LP), of ribonucleic acid phosphorus (RNAP) and of protein nitrogen (PN) in all cell types. If
expressed per cell it was found that R N A P was increased while LP
and PN showed no significant difference from the control value. There
was a linear relationship between glucose utilization and increase in
cell number in both normal and malignant human cells. Lieberman
and Ove (1959) also found that insulin enhanced cell multiplication
in cells from human appendix and the HeLa strain alike, and that,
independently of the level of insulin used, cell proliferation was directly
correlated with glucose consumption, i.e. that the hormone increased
the glucose uptake in normal and malignant cells alike. This is in
contrast to findings by Moretti and DeOme (1962) who found that
insulin stimulated the consumption of glucose in organ cultures of
are therefore advised to consult these chapters also for further information.
593
I I . E F F E C T S OF I N S U L I N A N D G R O W T H H O R M O N E
A. EFFECTS ON TISSUE A N D CELL C U L T U R E S
It is now recognized that insulin not only stimulates carbohydrate
metabolism, but that it also plays an important part in protein synthesis. Thus insulin stimulates rapid growth and increases the retention
of nitrogen in hypophysectomized animals (Lawrence, Salter and Best,
1954).
Cells derived from various different animal species and grown in
culture in the presence of insulin showed an increase of growth. Gey
and Thalhimer (1924) observed a marked stimulation of cell proliferation in cultures growing in a medium to which insulin had been
added. V o n Haam and Cappel (1940), who grew mouse-embryoheart fibroblasts with doses of insulin ranging from 0*001 to 1 unit/ml
of medium, reported an increase of the mitotic index and of cell
multiplication which ranged from twice the control value at the
lower concentrations to 9-10 times at the higher doses. An interesting
finding was that the treated cells showed a rapid accumulation of fat
droplets in their cytoplasm, which became more extensive with rising
doses of the hormone.
Leslie and Davidson (1951), Leslie (1952) and Leslie, Fulton and
Sinclair (1957) investigated the effect of insulin (0-1-3 /x/ml) on fresh
explants of chick-embryo heart, on human embryonic skin fibroblasts
and kidney cells and on three strains of human tumour cells, HeLa,
Hep 1 and Hep 2. Insulin promoted cell proliferation and increased
the total amount of lipid phosphorus (LP), of ribonucleic acid phosphorus (RNAP) and of protein nitrogen (PN) in all cell types. If
expressed per cell it was found that R N A P was increased while LP
and PN showed no significant difference from the control value. There
was a linear relationship between glucose utilization and increase in
cell number in both normal and malignant human cells. Lieberman
and Ove (1959) also found that insulin enhanced cell multiplication
in cells from human appendix and the HeLa strain alike, and that,
independently of the level of insulin used, cell proliferation was directly
correlated with glucose consumption, i.e. that the hormone increased
the glucose uptake in normal and malignant cells alike. This is in
contrast to findings by Moretti and DeOme (1962) who found that
insulin stimulated the consumption of glucose in organ cultures of
are therefore advised to consult these chapters also for further information.