Absence of endotoxin-fever but not hyperthermia in Brattleboro rats

I.c.v. administration of bacterial endotoxin produced a fever in the Long-Evans rat but not in the Brattleboro rat. Similar administration of arachidonic acid, prostaglandin E2, prostacyclin, dibutyryl cAMP, norepinephrine, morphine and beta-endorphin caused hyperthermia in both Long-Evans and Brattleboro rats. Variable doses of exogenous arginine vasopressin (AVP) when centrally administered with endotoxin caused fever in the Brattleboro rat. It is suggested that AVP may play an important role in the production and release of endogenous pyrogen.     

Interaction between the effects of centrally administered arecoline and leucocyte pyrogen on the activity of posterior hypothalamic neurons in the rabbit

Summary In experiments with urethane-anesthetized rabbits, the alteration in the activity of posterior hypothalamic neurons resulting from intracerebroventricular injection of leucocyte pyrogen was attentuated by subsequent administration of arecoline. Atropine failed to alter the neuronal response to leucocyte pyrogen but abolished the effect of arecoline. The neuronal response to arecoline was reversed in the absence of leucocyte pyrogen.     

Interaction between the effects of centrally administered arecoline and leucocyte pyrogen on the activity of posterior hypothalamic neurons in the rabbit

In experiments with urethane-anesthetized rabbits, the alteration in the activity of posterior hypothalamic neurons resulting from intracerebroventricular injection of leucocyte pyrogen was attenuated by subsequent administration of arecoline. Atropine failed to alter the neuronal response to leucocyte pyrogen but abolished the effect of arecoline. The neuronal response to arecoline was reversed in the absence of leucocyte pyrogen.     

Pyrogen fever in rabbits pretreated with p-chlorophenylalanine or 5, 6-dihydroxytryptamine.

The hyperthermic effect of a bacterial pyrogen has been studied in rabbits pretreated or not with p-chlorophenylalanine or 5, 6-dihydroxytryptamine. The results obtained indicate that a selective reduction of cerebral 5-hydroxytryptamine levels by these drugs do not significantly affect pyrogen hypertermia.     

Pyrogen fever in rabbits pretreated withp-chlorophenylalanine or 5,6-dihydroxytryptamine

Summary The hyperthermic effect of a bacterial pyrogen has been studied in rabbits pretreated or not withp-chlorophenylalanine or 5,6-dihydroxytryptamine. The results obtained indicate that a selective reduction of cerebral 5-hydroxytryptamine levels by these drugs do not significantly affect pyrogen hypertermia.     

Absence of endotoxin-fever but not hyperthermia in Brattleboro rats

Summary I. c. v. administration of bacterial endotoxin produced a fever in the Long-Evans rat but not in the Brattleboro rat. Similar administration of arachidonic acid, prostaglandin E₂, prostacyclin, dibutyryl cAMP, norepinephrine, morphine and -endorphin caused hyperthermia in both Long-Evans and Brattleboro rats. Variable doses of exogenous arginine vasopressin (AVP) when centrally administered with endotoxin caused fever in the Brattleboro rat. It is suggested that AVP may play an important role in the production and release of endogenous pyrogen.     

Lack of pyrogenic tolerance transmission between brain and periphery in the rabbit

Summary Successive injections of lipopolysaccharide (LPS) either intravenously (i.v.) or intracerebroventricularly (i.c.v.) induced pyrogenic tolerance to LPS in rabbits. Tolerance was shown by a decrease of the magnitude of the fever response to repeated doses of LPS, irrespective of the route of pyrogen administration. A significantly greater and more dramatic decrease of the fever index, however, was observed in rabbits made tolerant to pyrogen given i.v. than when the pyrogen was given i.c.v. Transmission of the pyrogenic toleraance between brain and peripheral tissues, however, has not been ascertained.     

Lack of pyrogenic tolerance transmission between brain and periphery in the rabbit

Successive injections of lipopolysaccharide (LPS) either intravenously (i.v.) or intracerebroventricularly (i.c.v.) induced pyrogenic tolerance to LPS in rabbits. Tolerance was shown by a decrease of the magnitude of the fever response to repeated doses of LPS, irrespective of the route of pyrogen administration. A significantly greater and more dramatic decrease of the fever index, however, was observed in rabbits made tolerant to pyrogen given i.v. than when the pyrogen was given i.c.v. Transmission of the pyrogenic tolerance between brain and peripheral tissues, however, has not been ascertained.     

Endogenous pyrogen formation by human blood monocytes stimulated by polyriboinosinic acid:Polyribocytidylic acid

The pyrogenic response to supernatants from human blood monocytes stimulated with polyriboinosinic acid:polyribocytidylic acid (poly I:C) was characteristic of a response to endogenous pyrogen in that it was brief and monophasic, and was destroyed by heating the supernatants at 70°C for 30 min. Pyrogen production was unimpaired when the incubations were carried out in the presence of cycloheximide (50 g/ml; an inhibitor of protein synthesis) or indomethacin (50 g/ml; an inhibitor of prostaglandin synthesis). Also, neither interferon, interleukins, tumor necrosis factor nor prostaglandin E₂ were detectable in the supernatants from the poly I:C-stimulated human monocytes.     

Über die Stoffwechselwirkung eines Lipopolysaccharids ausEscherichia coli

Summary It has been established that pyrogen causes hyperglycemia and diminution of the lactic acid level in the blood. Inin vitro investigations, oxygen requirements of the liver slices show marked increase. The results are regarded as showing a primary action of the pyrogens on metabolism.     

Biological activities of pure prostaglandins

Prostaglandins, the hydroxy unsaturated C20 fatty acids, are found throughout the body and have an equally wide range of biological activities. Prostaglandins are known to: 1) stimulate uterine contraction; 2) inhibit spontaneous contraction of the rabbit uterus; 3) inhibit the respiratory smooth muscle of different animals; 4) lower systemic arterial blood pressure when injected intravenously; 5) stimulate contractions in isolateral segments of intestinal smooth muscle of most species investigated; 6) produce transient sedation when intravenously injected in cats, and 7) inhibit lipolysis induced by catechal amines, corticotrophin, glucagon and thyroid stimulating hormone. The inhibitory and excitatory effects of prostaglandins may each have a physiological importance at different sites. Current state of knowledge of the distribution, metabolism and actions of the prostaglandins is still fragmentary. The functional significance of the prostaglandins is yet to be determined.     

Thermoadaptive influence on reactivity pattern of vasopressinergic neurons in the guinea pig

In cold-adapted guinea pigs, increased amounts of arginine-vasopressin (AVP) immunoreactive material could be visualized in neurons of the supraoptic and paraventricular nucleus, in fibers projecting to the neurohypophysis and in fiber terminals in the ventral lateral septum and in the amygdala. In warm-adapted animals the reactivity to AVP antiserum was poor in all neuronal structures examined. High AVP-immunoreactivity was accompanied by a reduced febrile response to bacterial pyrogen in cold-adapted guinea pigs.     

Thermoadaptive influence on reactivity pattern of vasopressinergic neurons in the guinea pig

Summary In cold-adapted guinea pigs, increased amounts of arginine-vasopressin (AVP) immunoreactive material could be visualized in neurons of the supraoptic and paraventricular nucleus, in fibers projecting to the neurohypophysis and in fiber terminals in the ventral lateral septum and in the amygdala. In warm-adapted animals the reactivity to AVP antiserum was poor in all neuronal structures examined. High AVP-immunoreactivity was accompanied by a reduced febrile response to bacterial pyrogen in cold-adapted guinea pigs.     

Effect of prostaglandins on skin tumorigenesis

Summary Concomitant administration of prostaglandins E₂ (PGE₂) and F₂ a(PGF₂ a) with a carcinogen, 3-methylcholanthrene (MCA) to mice for 2 months markedly enhanced the occurrence of squamous cell carcinomas. Only epidermal cell hyperplasia occurred in mice treated with MCA alone by that time. Radioactivity measurements and electron microscopic autoradiography revealed that prostaglandins stimulate DNA, RNA and protein synthesis in neoplastic cells. These findings indicate that PGE₂ and PGF₂ a can act as cocarcinogens on skin tumorigenesis.     

Plasma prostaglandin levels in fed and starved lean, normal and obese women.

The plasma obtained from fed and starved lean, normal and obese women was estimated, by a radio-immunoassay method, for prostaglandins, owing to their implication in the regulation of adipose tissue lipolysis and the development of obesity. No significant differences were found due to nutritional status or body-build. However, a significantly higher plasma concentration of prostaglandins of the E-type than of the F-type, was found consistently. The very low levels of prostaglandins observed (a range of 0.10--0.15 ng ml-1 for E-type and a range of 0.05--0.07 ng ml-1 for the F-type) may be due, in part, to the activity of a plasmatic prostaglandin metabolizing system.     

Plasma hormone levels in normal and lead-treated pregnant mice

Summary Dietary lead (0.5%) was given to mice which, after mating, exhibited a vaginal plug. Estradiol, progesterone and prostaglandins E and F 2 were determined in, the plasma by radioimmuno assay at different times thereafter. The increase in estradiol and decrease in prostaglandins prior implantation are not greatly altered by lead treatment, whereas the subsequent increase in progesterone and later in estradiol is abolished. It is concluded that the lower number of pregnancies seen in lead-treated mothers is due to a maternal hormonal imbalance caused by lead.Supported by contract 038-74-7 ENV B of the E.C. Environmental Research Program. Publication No. 1394 of the Euratom Biology Division.     

Plasma prostaglandin levels in fed and starved lean,normal and obese women

Summary The plasma obtained from fed and starved lean, normal and obese women was estimated, by a radio-immunoassay method, for prostaglandins, owing to their implication in the regulation of adipose tissue lipolysis and the development of obesity. No significant differences were found due to nutritional status or body-build. However, a significantly higher plasma concentration of prostaglandins of the E-type than of the F-type, was found consistently. The very low levels of prostaglandins observed (a range of 0.10–0.15 ng ml^–1 for E-type and a range of 0.05–0.07 ng ml^–1 for the F-type) may be due, in part, to the activity of a plasmatic prostaglandin metabolizing system.Acknowledgments. The authors are grateful to Dr D.C. Williams for his support and encouragement and to the Upjohn Company for the generous gift of standard prostaglandins.     

The effect of bradykinin on the electrical activity of rat jejunum

Summary Bradykinin increased the potential difference across both the jejunum and colon of the rat. This effect was significantly reduced by indomethacin, suggesting that it was mediated by prostaglandins. The possibility that bradykinin may contribute to the diarrhoea of the carcinoid syndrome by inducing a net secretory state in the intestine is discussed.     

The effect of bradykinin on the electrical activity of rat jejunum

Bradykinin increased the potential difference across both the jejunum and colon of the rat. This effect was significantly reduced by indomethacin, suggesting that it was mediated by prostaglandins. The possibility that bradykinin may contribute to the diarrhoea of the carcinoid syndrome by inducing a net secretory state in the intestine is discussed.