Insulin sensitivity of kininogen-deficient rats was compared with that of normal rats using euglycaemic hyperinsulinaemic glucose clamping. Anaesthetized animals were infused with 2-50 mU kg-1 min-1 of insulin and the glucose infusion rates needed to maintain euglycaemia were determined. Maximum glucose uptake, insulin sensitivity index and insulin clearance were reduced in kininogen-deficient rats. Captopril increased the amount of glucose needed to maintain euglycaemia during infusion of 2 and 10 mU kg-1 min-1 of insulin in normal rats, but had no effect in kininogen-deficient rats. Anaesthetized rats of both strains were given an intraperitoneal injection of glucose and the evolution of blood glucose was followed for 120 min. The peak increase was higher in kininogen-deficient rats. Similar larger increases in blood glucose were observed after glucose injection in normal rats previously treated with HOE 140, a bradykinin B2 receptor antagonist. After glucose injection, plasma insulin increased in both groups of rats but reached lower levels in kininogen-deficient animals. These results suggest that bradykinin is involved not only in the clearance of glucose and insulin by the tissues during insulin infusion but also that bradykinin can affect the release of insulin after a glucose load.

Injection of substance P (SP) in a rat hindpaw induced extravasation of 125I-labelled albumin in both hindpaws and salivation. Intravenous injection of SP dose-dependently increased vascular permeability. This latter effect was increased in rat paws by captopril, an inhibitor of angiotensin-converting enzyme (ACE), administered locally in combination with diprotin A, an inhibitor of an dipeptidyl(amino)peptidase IV (DAP IV) or phosphoramidon, an inhibitor of neutral endopeptidase (NEP). The increase in permeability induced by SP was inhibited by RP 67580, a NK1-receptor antagonist.

The salivary flow elicited by phenylephrine was reduced in kininogen-deficient rats or by pretreatment of normal Wistar rats with HOE 140, a bradykinin antagonist. Salivary flow induced by substance P was similar in normal and kininogen-deficient rats. Phenylephrine released large amounts of kallikrein in saliva. Isoproterenol was less active while pilocarpine and substance P induced a small secretion of kallikrein. The saliva produced by anaesthetized rats in response to heat stress contained low levels of kallikrein. However a large depletion of the kallikrein content of submaxillary glands was observed in awake animals exposed to 36 degrees C and 40 degrees C for one hour. This depletion was suppressed by prazosin administered with a beta-adrenergic antagonist. Administered alone, these drugs had no effect, whereas atropine increased the depletion. The presence of kallikrein was observed in the oedema fluid which developed around the submaxillary glands in rats pretreated with atropine or exposed to 40 degrees C. A consumption of plasma kininogens occurred during heat exposure. The reflex-induced release of kallikrein during heat exposure is mainly controlled by sympathetic nerves through activation of both alpha and beta-adrenoreceptors. This release induces the formation of kinins which participate to the thermolytic salivation.

Platelet-activating factor (PAF; 2.5 μg/kg) injected in the tail vein of anaesthetized rats increased the vascular permeability of the duodenum, paws, skin and muscles, as measured by the extravasation of 125I-labelled albumin. It did not affect the permeability of the lungs or the presence of labelled albumin in the liver and spleen. The effects of PAF were dose dependently inhibited by WEB 2086 (ID50: 1.39 to 2.09 mg/kg) and SM-12502 (ID50: 7.17 to 8.36 mg/kg). Zymosan, an activator of the alternative complement pathway (10 or 16 mg/kg), induced protein extravasation in the lungs, duodenum, paws and skin, and the accumulation of labelled albumin in the liver. The effects of zymosan on the duodenum and liver were dose dependently inhibited by WEB-2086 and SM-12502. Both PAF antagonists increased the effects of zymosan in the paws but they did not affect protein extravasation in the lungs. The hypotensive effect of PAF (0.5 μg/kg) was inhibited by WEB 2086 (ID50: 1.21 mg/kg) and SM-12502 (ID50: 13.4 mg/kg). Both PAF antagonists reduced the hypotensive effects of zymosan (4 or 16 mg/kg) with a similar relative inhibitory potency. PAF is the major mediator involved in the hypotensive effect of zymosan but plays only a minor role in the permeability-enhancing effect of zymosan, mostly in the splanchnic area.

The distribution in the nervous system of T-kininogen, the third kallikrein-resistant kininogen of the rat, was determined using bioassays and a radioimmunoassay system. In rat brain homogenates, trypsin released large amounts of a kinin-like myostimulating activity while urinary kallikrein released small amounts. The kinins released by trypsin were identified by HPLC as mostly T-kinin. Radioimmunoassays showed that a T-kininogen-like immunoreactive factor was uniformly distributed throughout the central nervous system. Higher levels were found in female rats than in male rats. Maximum levels were observed in newborn animals. A slight increase of T-kininogen content of the brain was observed after turpentine injection while T-kininogen level in liver was dramatically increased. T-kininogen plasma contamination to the nervous tissues was estimated by injecting 125I-labelled T-kininogen. The T-kininogen content of rat cultured cells and neurons was also examined. Highest levels were found in dorsal root ganglia neurons, lower levels in Schwann cells, phaeochromocytoma cells, mixed cells from spinal ganglion and in astrocytes. Immunocytochemistry showed the presence of T-kininogen in the cytoplasm of cultured dorsal root ganglia neurons and embryonic hippocampal neurons. The distribution of T-kininogen throughout the central and peripheral nervous system of the rat, the variations of its level during the life span suggest that T-kininogen would play the role of a cysteine proteinase inhibitor and not that of a T-kinin-releasing substrate in nervous tissues.

We studied the influence of aprotinin and soya bean trypsin inhibitor (SBTI) on the inflammatory reaction induced by the implantation of dry sponges in normal Wistar rats and in kininogen-deficient Brown Norway rats, during the first day after the implantation. In normal rats, aprotinin reduced the volume and total protein content of the exudates at 3 h but not thereafter. Aprotinin also markedly reduced the immunoreactive kinins and kallikrein in the exudates. Aprotinin did not modify the volume of the exudates of the Brown Norway rats. SBTI reduced the inflammatory reaction in both rat strains but did not significantly modify the formation of immunoreactive kinins. The inflammatory reaction developed more slowly in Brown Norway rats. The kinin system is thus involved during the first hours of the development of this acute inflammatory reaction. The anti-inflammatory effect of SBTI does not depend on the inhibition of kinin formation.

Kinins were measured by a radioimmunoassay in the inflammatory exudates induced by carrageenin or zymosan in the peritoneal cavity of normal Wistar rats and of kininogen‐deficient Brown Norway rats. After administration of carrageenin to normal rats, levels of immunoreactive kinins showed a single peak during the first two hours and then decreased. The presence of kinins preceded and accompanied the exudation of 125I‐labelled albumin. Kinins were identified as bradykinin by chromatography. Captopril, an inhibitor of kininase 2, increased the level of kinins and the volume of the exudates after carrageenin treatment. In Brown Norway rats, the volume of the exudates was small and contained little or undetectable amounts of immunoreactive kinins. During zymosan‐induced peritonitis, the exudates were devoid of immunoreactive kinins in both species. The volume of the exudates was larger in kininogen‐deficient rats than in normal rats. We conclude that in rats, the kinin system is a major factor responsible for the development of the inflammatory reactions induced by carrageenin, but is not involved in the reactions induced by zymosan.

The involvement of the high molecular weight rat kininogen in the activation of the rat contact system by kaolin-cephalin, kaolin, sulfatides and ellagic acid has been investigated, using a rat plasma congenitally devoid of this kininogen. Coagulation times induced by these activators were shorter in normal as well as in deficient rat plasma than in normal human plasma. Coagulation times were prolonged in deficient rat plasma, when the incubation times was three min or less. By kaolin or cephalin-kaolin, this prolongation disappeared when the incubation time reached ten min. The activation of plasma prekallikrein developed slowly in deficient plasma with all the triggers but reached control level after ten min of incubation. By kaolin-cephalin, the activation of Hageman factor was weak and slow in deficient plasma during the ten min of incubation.In rat, high molecular weight kininogen plays thus a role in the activation of the contact system by these triggers. But this role seems to be less important than in human plasma.

A rapid and convenient three-step purification scheme has been developed for the purification of T-kininogen (alpha 1-cysteine proteinase inhibitor) from rat plasma. The purification process includes chromatography on hydroxyapatite, immunoaffinity chromatography and gel filtration. This procedure is applied to plasma from the brown Norway rat which is known to be deficient in high and low molecular weight kininogens. The method furnished large amounts of T-kininogen from turpentine-treated Wistar rats as well as from untreated and turpentine-treated deficient brown Norway rats. The amino acid and hexose content of the three T-kininogens has been determined. While the composition of the molecules isolated from both injured rats was similar, the neutral sugar content of T-kininogen purified from untreated brown Norway rats was lower and its amino acid composition showed slight differences. The three molecules have identical behaviour and similar physicochemical and immunological properties when analysed by SDS electrophoresis, isoelectrofocusing and two-dimensional immunoelectrophoresis.

Antibodies raised in rabbits against rat T-kininogen (alpha1-cysteine proteinase inhibitor) were used to develop a radioimmunoassay and a nephelometric quantification for T-kininogen. These assays were specific and analytically reliable. We also described a radioimmunoassay for kinin measurement. These immunological methods have been used to study the behaviour of T-kininogen during inflammatory processes and specify the two properties of this kind of kininogen: its inhibitory capacity towards cysteine proteinases and its activity as precursor of T-kinin. Control plasma level of T-kininogen in male rats was lower than that of female rats. The maximum level was observed in plasma, liver, kidney and uterus of female rats during metestrus. After turpentine injection, T-kininogen level increased not only in plasma but also in liver and kidney. In carrageenan-induced peritoneal exudates, we found a large accumulation of T-kininogen and of immunoreactive kinins, these latter being identified by HPLC as bradykinin.

The content of kinins and T‐kininogen (the third kininogen) in exudates induced by the subcutaneous implantation of saline‐soaked sponges have been measured by radioimmunoassay in normal Wistar rats and in Brown Norway rats from a strain which is deficient in high and low molecular weight kininogens. In both strains, sponge implantation induced a rise of T‐kininogen in plasma with subsequent accumulation in the sponge exudate. This accumulation correlated with the extravasation of plasma proteins during the first 6 h. Bioassays showed that the T‐kinin moiety was retained in T‐kininogen. In Wistar rats, a large release of immunoreactive kinins up to a mean value of 6.4 ng ml −1 was observed during the first 6 h and on the second day after the implantation. In Brown Norway rats, the kinin level in the exudates did not exceed 0.53 ng ml −1 . Of the kinins present during the first 6 h in the exudates withdrawn from Wistar rats, 60% were identified by high performance liquid chromatography as bradykinin. The volume of the exudate induced by the implantation of dry sponges was smaller in Brown Norway rats than in Wistar rats. We conclude that the role of T‐kininogen in this kind of exudate was mainly the inhibition of thiol proteinases and not the release of T‐kinin. In Wistar rats, bradykinin acts as a pro‐inflammatory factor during the first hours and may play a role during the healing process.

Catechin dimers induce a large long-lasting oedema when injected in the paw of the rat. This oedema is not inhibited by methysergide, promethazine, indomethacin, phenidone, bromophenacyl bromide and colchicine. It is not modified in rats made leukopenic by methotrexate. It is slightly delayed in Brown Norway rats which were kallikrein-kininogen deficient. Similarly catechin dimers induce the formation of a large peritoneal exudate in the rat. The exudate contains insignificant levels of leucocytes and 5-hydroxytryptamine. It contains kinins but its PG content is very low. The exudate does not activate (14C)-arachidonic acid into PG. Catechin dimers induce kinin formation in rat plasma "in vitro". They inhibit the formation of PG and HETE-like compounds from (14C)-arachidonic acid by rat peritoneal cells "in vitro". Catechin dimers administered at sub-irritant doses reduced carrageenan-induced oedema. Catechin dimers at low doses have an anti-inflammatory effect which may depend on PG synthesis inhibition. At larger doses, they induce inflammatory responses which occur with almost complete lack of participation of PG.

The influence of serum from normal and turpentine-treated rats on prostaglandin synthesis by peritoneal cells has been investigated. Both types of serum had the same inhibitory effect on the formation of myostimulating prostaglandin-like substances and of 14C-PGE2 by rat peritoneal cells in the presence of 82 or 100 mumol of arachidonic acid. On guinea-pig peritoneal cells, the serum from turpentine-treated rats had a smaller inhibitory effect than normal serum on 14C-PGE2 and 14C-HETE formation from 2 mumol of arachidonic acid. Thus the acute inflammatory reaction produced by turpentine did not increase the inhibitory effect of rat serum on prostaglandin synthesis. It is suggested that the anti-inflammatory effect of counter irritation by turpentine does not depend on prostaglandin synthesis inhibition but has to be attributed to some other mechanisms.

1. Rat serum levels in beta-glucuronidase and beta-galactosidase are higher than plasma levels. Rat platelets release these lysosomial enzymes during blood coagulation in vitro. 2. After anaphylactic shock, in the sensitized rat, there is no increase in beta-galactosidase and beta-glucuronidase plasma levels. The tissues of the sensitized rat do not release these enzymes during the antigen-antibody reaction. The blood platelet level is diminished after anaphylactic shock and the serum levels of the lysosomial enzymes are decreased. 3. In thrombopenic rat, anaphylactic shock is identical as in control animals. Rat platelets do not play a significant role in the anaphylactic shock.