[Frequency and phase correlations of the biorhythms of metabolic indices in mice during their postnatal ontogeny]

In laboratory mice the daily rhythms of feeding, plasma insulin, blood glucose and liver glycogen were investigated beginning from an age of 1 week to 52 weeks. For all parameters circadian and ultradian rhythms changing in the course of development could be quantified. During juvenile phase and inversion of all patterns connected with temporary increasing ultradian components takes place. The beginning and the end of this inversion are specific for various parameters, to that changing frequency and phase correlations could be obtained. The lowest degree of phase correspondence is found at weaning, it reaches its maximum in adults and decreases again in older mice. The possible consequences of demonstrated phenomena for the stability of the functional system and the existence of sensitive phases during postnatal ontogeny are discussed.