During trypsin perfusions in normal rabbits and in rabbits in acute phase reaction (APR), there is no modification in cardiorespiratory functions except in the instant preceding death. The fibrinogen level decreases and fibrin is deposited in the vascular lumen. The alpha 2 macroglobulin (alpha 2 M) content diminishes more rapidly than the alpha I macroglobulin (alpha I M) content; moreover, in subjects in APR, the decrease of alpha I M is further slowed with increasing perfusion rates, whereas the decrease in alpha 2 M remains constant. All the alpha M are completely combined at death. Therefore, it can be assumed that only the hepatic filtering of the alpha I M enzyme complex is subject to saturation.

1.1. The study of the evolution of α-1 and α-2-macroglobulin levels in the rabbit fetus and newborn reveals an analogy between α-1-macroglobulin in the rabbit and α-2-macroglobulin in humans.

1. The development of the progressive antithrombinic activity in rabbit plasma as a function of the level of the two alpha-macroglobulins in two experimental pathologies: acute phase inflammatory reaction and nephrotic syndrome, were studied. 2. In the first case, the antithrombinic activity is a result of the increased biosynthesis of plasmatic antithrombins: antithrombin III, alpha 1 antitrypsin and alpha macroglobulins. 3. In the nephrotic syndrome, this activity follows the increase in the alpha M levels, the other antithrombins having been massively eliminated from the circulation in the urine.

Immunological methods associated with a kinetic study of blood coagulation allowed us to show the influence of the 2 rabbit alpha macroglobulins on the plasma progressive antithrombin activity. This study allowed the authors to discuss the participation of the alpha macroglobulins during the fibrinoformation and to think that these proteins have an immediate antithrombin activity.

A purification process of rabbit alpha 1 M and alpha 2 M from plasma was described: first the platelets, the fibrinogen, the plasminogen and the low-density lipoproteins were eliminated; then alpha 1 M and alpha 2 M were purified by gel filtration on Sephadex G 200 and by chromatography on DEAE-cellulose. These purified materials were then isotopically labeled allowing the study of the proteins metabolism.

Rabbit alpha-1-M and alpha-2-M labelling was carried out in vitro with 131I and in vivo with 75-Seleno-methionine in order to determine the half-life of these proteins. alpha-2-M catabolism is faster than the alpha-1-M one. This result is the same when these proteins were obtained from a plasma of a rabbit exhibiting an inflammatory reaction though their half life was shorter.

1.1. Some components of rat proteinuria were studied in normal and nephritic rat urine. Immunoelectrophoretic methods were used after Sephadex G 200 chromatography.2.2. α-1-macroglobulin, γ globulins, haptoglobin, and orosomucoid were present in normal and nephritic rat urine.3.3. Ceruloplasmin and transferrin were not found in normal rat urine.

1.1. Pubescent and prepubescent rats were injected with nephrotoxic serum in order to induce nephritis.2.2. Using Sephadex G 200 chromatography, we noted an exclused and a diffused fraction in each case, in normal and nephritic rat urines. A third peak appeared in pathological cases.3.3. Maximum absorbance of the 2 first peaks was unrelated with the total proteinuria which varied during the experimental disease course.4.4. Quantitative analysis of the total proteinemia and α-macroglobulins did not differ in normal and nephritic rat serum. We noted a diminution in albumin, β and γ globulins. Immunoelectrophoretical methods revealed a bifid precipitin line of the γ globulins. The presence of a pre-albumin in prepubescent rat serum lead us to suppose that Masugi nephritis symptoms are different according to the age of the rat.

Using chromatographic technique on "Sephadex G 200" associated to immunologic qualitative and quantitative techniques, the authors showed that the alpha1-macroglobulin is present in normal Rat urines. This protein is also present in urines obtained during the Masugi nephritis. The alpha1-macroglobulin concentration observed in the different urine samples is unrelated to the total proteinuria evolution. The results given allow us to discuss the mechanisms of the glomerular filtration.