COMPARISON OF ULTRADIAN AND CIRCADIAN OSCILLATIONS OF CARBON-DIOXIDE PRODUCTION BY VARIOUS ENDOTHERMS

Carbon dioxide emission (VCO2) was computed every 20 min from continuo us CO2 concentration recordings taken during 3-30 consecutive days, in strictly controlled environmental conditions, in 54 OF1 mice, 99 Japa nese quail, 66 Sprague-Dawley rats, 50 Hartley guinea pigs, 7 chicks, for 1-15 days on 2 Cynomolgus monkeys, and for 24 h on 7 premature inf ants. This VCO2 shows circadian and ultradian oscillations that were a nalyzed for frequencies and amplitudes in Light-dark 12-h alternation (LD 12:12), continuous light (LL), and continuous dark (DD). Circadian s were not always identified or were often masked in LL or DD (mostly in guinea pigs, quail, and rats), while ultradians (tau greater than o r equal to 40 min) were found in all species, at every time, and in al l light regimens. Analysis of variance and chi(2) show significant (P < 0.001) interspecies differences for ultradian (1.07 < tau < 1.40 h) intervals and for circadian and ultradian VCO2 amplitudes. Relationshi ps between ultradian and circadian VCO2 oscillations differ according to the species, ultradians appearing as an entity characteristic for e ach endotherm species.