title: Possible human endogenous cryogens.
abstract: Anapyrexia, which is a regulated fall in core temperature, is beneficial for animals and humans when the oxygen supply is limited, e.g., hypoxic, ischemic, or histotoxic hypoxia, since at low body temperature the tissues require less oxygen due to Q(10). Besides hypoxia, anapyrexia can be induced various exogenous and endogenous substances, named cryogens. However, there are only a few reports investigating endogenous cryogens in mammals. We have experienced one patient who suffered from severe hypothermia. The patient seemed to be excessively producing endogenous peptidergic cryogenic substances the molecular weight of which may be greater than 30 kDa. In animal studies, the patient's cryogen appeared to affect metabolic functions, including thermogenic threshold temperatures, and then to produce hypothermia. Since endogenous cryogenic substances may be regarded as useful tool in human activities, e.g., during brain hypothermia therapy or staying in a space station or spaceship, further studies may be needed to identify human endogenous cryogens.
authors.affiliation: Department of Environmental Physiology, School of Medicine, Shimane University, Izumo 693-8501, Japan. o-shido@med.shimane-u.ac.jp
authors.forename: Osamu
authors.initials: O
authors.lastname: Shido
authors.forename: Naotoshi
authors.initials: N
authors.lastname: Sugimoto
mesh_terms: D058633:Antipyretics / Q000378:metabolism*; D001833:Body Temperature Regulation / Q000502:physiology*; D006801:Humans; D007035:Hypothermia / Q000378:metabolism* / Q000503:physiopathology; D007036:Hypothermia, Induced / Q000379:methods; D010455:Peptides / Q000378:metabolism*; D022722:Thermogenesis / Q000502:physiology
chemical_list: D058633:Antipyretics; D010455:Peptides