17.
A C T I O N S O F
V I T A M I N S A
A N D
C
689
and extended by Robertson (1961) who isolated labelled collagen
hydroxyproline from suspensions of scorbutic carrageenan granulomas
to which ASA and
1 4
C proline had been added in vitro. This and other
less conclusive evidence suggests that the action of ASA on collagen
synthesis is exerted at the cellular level.
The evidence from tissue cultures is contradictory. Jeney and Toro
(1936) found increased collagen-formation upon addition of ASA to
fibroblasts cultivated in normal plasma with or without embryo extract.
Similarly Querido and Gaillard (1939) observed that 16-day chickembryo frontal-bone rudiments formed fewer collagen bundles in
scorbutic guinea-pig plasma than in normal plasma, and this difference
disappeared after adding vitamin C.
On the other hand, Hass and McDonald (1940) could not demonstrate any influence of ASA concentration on fibrogenesis in cultures of
rat and guinea-pig lung and spleen provided the physiological p H of
the medium was maintained. Di Fiore and Sacerdote de Lustig (1943)
studied the effect of ASA deprivation in vitro on cultures of loose connective tissue, myocardium, smooth and striated muscle and epithelial
tissues of 3-14-day-old chick embryos and could find no difference
in collagen formation between controls in normal plasma plus embryo
extract and test cultures in scorbutic or oxygenated guinea-pig plasma
plus 3-day chick-embryo extract. This was used on the assumption,
probably stemming from the work of Ray (1934) and of Barnett and
Bourne (1942), that the early embryo has no vitamin C, but actually
the ASA concentration is very high at that stage (Rinaldini, 1960).
Sacerdote de Lustig (1944a) continued this work by using plasma of
guinea-pigs kept on high C diets and adding ASA to the culture medium,
and failed to find any stimulating effect on the production of collagen
fibres.
All this early work was based on purely morphological and subjective
criteria, and the ASA content of the culture media was not precisely
known. Lately Woessner and Gould (1957) reinvestigated the problem
applying the quantitative culture methods of Gerarde, Jones and Winnick (1952) combined with chemical estimations of hydroxyproline, and
concluded from well-controlled experiments that chick embryonic lung
can form as much collagen in complex or synthetic media containing
less than 1 /*g/ml ASA as in media supplemented with 50-100 /xg/ml
ASA. Concentrations of 200 /xg/ml or higher caused some inhibition of
collagen formation. The ASA content of the unsupplemented cultures
dropped to less than half its initial value after 3 days, and the possibility of ASA synthesis by the cells was discarded on those grounds.
There is no doubt that collagen formation is one of the more thoroughly studied biological functions of vitamin C, and yet its importance
A C T I O N S O F
V I T A M I N S A
A N D
C
689
and extended by Robertson (1961) who isolated labelled collagen
hydroxyproline from suspensions of scorbutic carrageenan granulomas
to which ASA and
1 4
C proline had been added in vitro. This and other
less conclusive evidence suggests that the action of ASA on collagen
synthesis is exerted at the cellular level.
The evidence from tissue cultures is contradictory. Jeney and Toro
(1936) found increased collagen-formation upon addition of ASA to
fibroblasts cultivated in normal plasma with or without embryo extract.
Similarly Querido and Gaillard (1939) observed that 16-day chickembryo frontal-bone rudiments formed fewer collagen bundles in
scorbutic guinea-pig plasma than in normal plasma, and this difference
disappeared after adding vitamin C.
On the other hand, Hass and McDonald (1940) could not demonstrate any influence of ASA concentration on fibrogenesis in cultures of
rat and guinea-pig lung and spleen provided the physiological p H of
the medium was maintained. Di Fiore and Sacerdote de Lustig (1943)
studied the effect of ASA deprivation in vitro on cultures of loose connective tissue, myocardium, smooth and striated muscle and epithelial
tissues of 3-14-day-old chick embryos and could find no difference
in collagen formation between controls in normal plasma plus embryo
extract and test cultures in scorbutic or oxygenated guinea-pig plasma
plus 3-day chick-embryo extract. This was used on the assumption,
probably stemming from the work of Ray (1934) and of Barnett and
Bourne (1942), that the early embryo has no vitamin C, but actually
the ASA concentration is very high at that stage (Rinaldini, 1960).
Sacerdote de Lustig (1944a) continued this work by using plasma of
guinea-pigs kept on high C diets and adding ASA to the culture medium,
and failed to find any stimulating effect on the production of collagen
fibres.
All this early work was based on purely morphological and subjective
criteria, and the ASA content of the culture media was not precisely
known. Lately Woessner and Gould (1957) reinvestigated the problem
applying the quantitative culture methods of Gerarde, Jones and Winnick (1952) combined with chemical estimations of hydroxyproline, and
concluded from well-controlled experiments that chick embryonic lung
can form as much collagen in complex or synthetic media containing
less than 1 /*g/ml ASA as in media supplemented with 50-100 /xg/ml
ASA. Concentrations of 200 /xg/ml or higher caused some inhibition of
collagen formation. The ASA content of the unsupplemented cultures
dropped to less than half its initial value after 3 days, and the possibility of ASA synthesis by the cells was discarded on those grounds.
There is no doubt that collagen formation is one of the more thoroughly studied biological functions of vitamin C, and yet its importance