[Biologically active substances in the tissues of hibernating animals]

It was supposed that the transitional period from euthermia to hibernation rather than the period of winter hibernation is optimal for the secretion of biologically active substances in rodent tissues. This hypothesis was tested in experiment. The maximal O2 consumption suppression was noted in mice after I. P. Injection of blood plasma from suslik Citellus undulatus at the beginning of its entering into hibernation. Low-molecular peptide fraction appearance in C. undulatus blood before hibernation was revealed by electrophoresis in gel and autoradiography. But its traces disappear by the end of bout. The endogenic inhibitory factor's maximal influence in early bout was shown by experiments with TRH and neoklotorphin (NKT). I.P. injections of these substances to C. undulatus were ineffective in the beginning of entering into hibernation, but clearly caused awakening after hibernation, has started. KT, being a fragment of NKT, inhibited suslik's heart rate when the awakening was provoked in the middle, but not in the end of bout. Possible transformation of biologically active substances in winter-hibernating rodents tissues is discussed. The KT "inhibitor" and NKT "stimulator" are supposed to pertain to the special type of regulatory peptides, that manage the hibernation cycle. One of the ways of inactivation of endogenic "hibernation trigger" is its removal from the organism with urine. The urine, taken from suslik immediately after hibernation proved to produce the greatest hypothermic effect on mice, I.P. injected with it.