From Big Medical Encyclopedia

THE PYROGENIC SUBSTANCES (grech, pyr fire + gennao to create, make; synonym pyrogens) — biologically active agents exogenous (bacterial and virus) and an endogenous (cellular and fabric) origin, having property to cause the reorganization of level of regulation of a temperature homeostasis leading to fervescence and development of fever.

Exogenous P. do not affect century directly the centers of thermal control; their pyrogenic activity is mediated through education secondary, endogenous, by P. century in an organism. Such ability also metabolites of steroid hormones, synthetic hemotoksi-chesky peptides and interferonogenny double-helix RNA have. The highest biol, activity the lipopolisakharida of gram-negative bacteria capable to increase body temperature possess, to stimulate a hypophysis - adrenal system, leykotsitopoez, synthesis of immunoglobulins, education and allocation with secondary P.' leukocytes of century, interferon, prostaglandins, to slow down cicatricial and commissural processes, etc. Drug belongs to exogenous P. century pyrogenal (see) which is widely applied to treatment hron, inflammatory diseases, as nonspecific means for treatment of syphilis; stimulations of regenerator processes. Also other ways of a pyrogene therapy are developed (see. Pyrotherapy ).

Endogenous P. are formed century in an organism at bacterial P.' action century and the exogenous factors causing an inflammation and also at immunopathological processes with participation of lymphokines (see. Fever ). The main source of endogenous P. of century are monocytes of blood, alveolar and peritoneal macrophages, the fixed macrophages of a spleen and liver, and also neutrocytes and eosinophils; they are spontaneously synthesized by cells of some tumors. Endogenous P.' education is carried out by leukocytes only in the conditions of pathology at interaction with various irritants century and proceeds in two phases: phase of activation and phase of release of pyrogen. The thermolabile protein produced by leukocytes P. century (leukocytic pyrogen) about a pier. it is powerful (weighing) 10 000 — 45 000 has in the cleared look high pyrogenic activity; stimulates leykotsitopoez, synthesis of immunoglobulins and proteins (fibrinogen, a gaptoglobin, ceruloplasmin, S-re-aktivnogo protein). In an acute phase of an inflammation leukocytic pyrogen has no specific pyrogenic specificity. Endogenous P.' opening allowed to prove sovr, the unitary theory of fever century. They play a role of proteinaceous mediators; their action on the Hypothalamic centers of thermal control through prostaglandins and cyclic nucleotides leads to the shift of level of regulation of temperature, turning on of the device physical and химической^ thermal controls, to development of fever.

Pharmakol, the drugs increasing body temperature due to selective effect on separate links of the device of thermal control or energy balance (2-4 - alpha dinitrophenol, caffeine, lysergic to - that, etc.), century do not belong to P.

Bibliography: Veselkin P. N. Fever, M., 1963; Dzheksenbayev O. Sh. and Seleznyova V. P. Leukocytic pyrogens, Zhurn, mikr., epid, and immun., No. I, page 50, 1977; Fish to and N and E. G. and Sorokin A. V. Studying of mechanisms of activation of leukocytes in the course of formation of leukocytic pyrogen, Bulletin Ekspery, biol, and medical, t. 86, J\o 8, page 203, 1978; Sorokin A. V. Pyrogens, JI., 1965; Cebu-1 and T. A. and. lake of Synthesis of four endogenous pyrogens by rabbit macrophages, J. Lab. clin. Med., v. 94, p. 95, 1979; D i-n a r e 1 1 about Page A. Production of endogenous pyrogen, Fed. Proc., v. 38, p. 52, 1979; Kampschmidt R. F. Leu-eocytic endogenous mediator, J. reticuloendoth. Soc., v. 23, p. 287, 1978; Pyrogens and fever, ed. by G. E. W. Wolstenholme a. J. Birch, p. 81, Edinburgh — L., 1971.

A. V. Sorokin.