164
R. LALLIER
dinitrophenol, a decoupling agent of phosphorylations bound to
oxidations. The vegetalizing effects of dinitrophenol however present
very peculiar aspects. Vegetalization is only obtained on isolated animal
halves and only very irregularly. The decoupling action of the dinitrophenol is accompanied by an increase of oxygen consumption. Lithium,
on the contrary, diminishes the consumption of oxygen. Its mode of
action seems then different from that of dinitrophenol. Another
uncoupling agent, dinitro-o-cresol, enhances the vegetalizing action of
lithium (Lindahl, 1940). Nevertheless, it is not possible to reach a
conclusion until we know what effects lithium has upon the equilibrium
between the reactions of phosphorylation and dephosphorylation. It is
also necessary to study the effects on development of several other
decoupling agents, and to compare them with the effects of lithium.
Lallier ( 1961a, b) has recently shown that nucleosides such as adenosine
and inosine protect the sea urchin egg against the vegetalizing effects of
lithium. According to Dische's suggestion (1951), these nucleosides
contribute to the formation of ATP and of different phosphoric esters.
The nucleosides are metabolized via a nucleoside Phosphorylase reaction
into ribose-1-phosphate; ribose-1-phosphate is further metabolized via
hexosemonophosphate shunt and glycolysis into various other phosphate
esters. The researches of Gabrio and others (1956) on the metabolism of
adenosine in erythrocytes confirm Dische's suggestion. The fact that the
hexosemonophosphate shunt is functional in the sea urchin egg indicates
that here also, the nucleosides can contribute to the formation of ATP.
ATP has been shown to counteract the vegetalizing action of lithium to
some extent (Kriszat and Runnström, 1957; Lallier, 1961b). Adenosine
and inosine moreover present a complete series of remarkable effects
upon erythrocytes. They protect them against the manifestations of
structural and metabolic degeneration observed during ageing. They
maintain their glycolytic activity at a high level and delay the formation
of inorganic phosphate while maintaining their content of phosphoric
esters, rich in energy, at a high level (Rubinstein et dl., 1956; Prankerd
and Altman, 1954). It is possible then to suggest that the protection
provided by the nucleosides against the effects of lithium is at least
partly connected to an action of the nucleosides upon glycolysis and the
formation of phosphoric esters. The study of the effects of the nucleosides
is only just beginning ; it may show itself to be rich in information about
the mode of action of lithium.
Runnström (1928b) has shown that potassium counteracts the vegetalizing effects of lithium. This action is specific to potassium; it is
not observed with other alkali ions (Lallier, 1960d). Potassium also
suppresses the inhibition of respiration induced by lithium in the sea
urchin egg (Lindahl, 1936) and in the frog egg (Lallier, 1955b). These
R. LALLIER
dinitrophenol, a decoupling agent of phosphorylations bound to
oxidations. The vegetalizing effects of dinitrophenol however present
very peculiar aspects. Vegetalization is only obtained on isolated animal
halves and only very irregularly. The decoupling action of the dinitrophenol is accompanied by an increase of oxygen consumption. Lithium,
on the contrary, diminishes the consumption of oxygen. Its mode of
action seems then different from that of dinitrophenol. Another
uncoupling agent, dinitro-o-cresol, enhances the vegetalizing action of
lithium (Lindahl, 1940). Nevertheless, it is not possible to reach a
conclusion until we know what effects lithium has upon the equilibrium
between the reactions of phosphorylation and dephosphorylation. It is
also necessary to study the effects on development of several other
decoupling agents, and to compare them with the effects of lithium.
Lallier ( 1961a, b) has recently shown that nucleosides such as adenosine
and inosine protect the sea urchin egg against the vegetalizing effects of
lithium. According to Dische's suggestion (1951), these nucleosides
contribute to the formation of ATP and of different phosphoric esters.
The nucleosides are metabolized via a nucleoside Phosphorylase reaction
into ribose-1-phosphate; ribose-1-phosphate is further metabolized via
hexosemonophosphate shunt and glycolysis into various other phosphate
esters. The researches of Gabrio and others (1956) on the metabolism of
adenosine in erythrocytes confirm Dische's suggestion. The fact that the
hexosemonophosphate shunt is functional in the sea urchin egg indicates
that here also, the nucleosides can contribute to the formation of ATP.
ATP has been shown to counteract the vegetalizing action of lithium to
some extent (Kriszat and Runnström, 1957; Lallier, 1961b). Adenosine
and inosine moreover present a complete series of remarkable effects
upon erythrocytes. They protect them against the manifestations of
structural and metabolic degeneration observed during ageing. They
maintain their glycolytic activity at a high level and delay the formation
of inorganic phosphate while maintaining their content of phosphoric
esters, rich in energy, at a high level (Rubinstein et dl., 1956; Prankerd
and Altman, 1954). It is possible then to suggest that the protection
provided by the nucleosides against the effects of lithium is at least
partly connected to an action of the nucleosides upon glycolysis and the
formation of phosphoric esters. The study of the effects of the nucleosides
is only just beginning ; it may show itself to be rich in information about
the mode of action of lithium.
Runnström (1928b) has shown that potassium counteracts the vegetalizing effects of lithium. This action is specific to potassium; it is
not observed with other alkali ions (Lallier, 1960d). Potassium also
suppresses the inhibition of respiration induced by lithium in the sea
urchin egg (Lindahl, 1936) and in the frog egg (Lallier, 1955b). These