ON THE BIOLOGICALLY-ACTIVE SUBSTANCES IN WINTER-HIBERNATING RODENTS

It was supposed that the transitional period from euthermia to hiberna tion rather than the period of winter hibernation is optimal for the s ecretion of biologically active substances in rodent tissues. This hyp othesis was tested in experiment. The maximal O-2 consumption suppress ion was noted in mice after I. P. injection of blood plasma from susli k Citellus undulatus at the beginning of its entering into hibernation . Low molecula peptide fraction appearence in C. undulatus blood. befo re hibernation was revealed by electrophoresis in gel and autoradiogra phy. But its traces disappear by the end of bout. The endogenic inhibi tory factor's maximal influence in early bout was shown by experiments with TRH and neokiotorphin (NKT). I. P. injections of these substance s to C, undulatus were ineffective in the beginning of entering into h ibernation, but clearly caused awakening after hibernation, has starte d. 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. Pos sible transformation of biologically active substances in winter-hiber nating rodents tissues is discussed. The KT <<inhibitor>> and NKT <<st imulator>> are supposed to pertain to the special type of regulatory p eptides, that manage the hibernation cycle. One of the ways of inactiv ation of endogenic <<hibernation trigger>> is its removal from the org anism with urine. The urine, taken from suslik immediately after hiber nation proved to produce the greatest hypothermical effect on mice, I. P. injected with it.