6lO REGENERATION AND GROWTH 7 



TABLE 8 



EXAMPLES OF BICYCLIC FLUCTUATIONS DURING REGENERATION 



Nature of fluctuation Reference 



Rate of mitosis in epidermis of newts' limb Manner, 1953 



Activity of alkaline phosphatase in newt's limb ^ Ghiretti, 1950; Karczmar and 



)Berg, 1 95 1 



Activity of alkaline phosphatase in mammalian skin \ Danielli et al., 1946; 



/Bourne, 1948 

 Activity of alkaline phosphatase in mammalian liver Norberg, 1950 



Activity of acid phosphatase, mammalian nerve Heinzen, 1947 



Acetyl phosphatide concentration, rat liver Yarbro and Anderson, 1954 



Acetyl choline activity see p. 643 



Ali esterase activity, mammalian nerve Cavanagh and Webster, 1955 



Lactic acid, concentration, mammalian liver Novikoff and Potter, 1948 



Concentration of a number of constituents per cell, Tsuboi et al., 1954 



mammalian liver 

 Nitrogen-output, Carcinus limb Needham, 1955 



Activity of N-corticoids see p. 643 



events as a local adaptation syndrome, and shows that the systemic response is 

 necessary for the success of the local processes, during regeneration [cf. Schotte 

 and Chamberlain, 1955). One characteristic of the GAS is that its progressive 

 phase or "phase of resistance" improves on repeated evocation up to a certain 

 limit and then progressively deteriorates ("phase of exhaustion") ; this closely 

 parallels changes in regenerative power (Fig. 4) on repeated evocation (Needham, 

 1949b). Here there appears to be evidence of resemblance even to the temporary 

 depression in response at the second evocation, before resistance develops (Selye, 

 1948). It seems probable that even the smallest stimulus, to the most obscure nerve, 

 causes some degree of "stress", followed by recovery. 



The precise significance of the excessive flow of nitrogen and other elements is 

 still far from clear (Needham, 1952), but it may be significantly linked with the 

 processes of regeneration. Crofts and Peters (1945) and Williamson and Fromm 

 (1955) concluded that it was necessary to supply adequate amounts of "key" amino 

 acids, in particular of methionine (Localio, etal., 1948, 1949; Bertolani ^/ a/., 1954), 

 the other acids therefore being deaminated. Liver-methionine in fact is used to 

 supply cystine for regenerating skin (Williamson and Fromm, 1955) and muscle- 

 protein is used to provide amino acids for regenerating liver (Man et at. 1946). 

 The variation of flow with variations in protein intake however implies that it 

 is not an invariable indispensable process. 



The only evident contrast between local and systemic metabolism is that oxygen- 

 consumption increases systemically during the R-phase (Cuthbertson, 1944), 

 after a brief fall associated with increased glycolysis (Malaguti and Vaccari, 

 1954). Perhaps differences of this kind necessitate the development of a barrier be- 

 tween the regenerate and the rest of the body (Needham, 1952, p. 22; Singer et at., 



1954)- 



A simple oscillation in metabolism from R- to P-phases is not universal. A num- 



