Alpha 2-macroglobulins Research Articles

Assembly of an atypical \u03b1-macroglobulin complex from Pseudomonas aeruginosa

Alpha-2-macroglobulins (A2Ms) are large spectrum protease inhibitors that are major components of the eukaryotic immune system. Pathogenic and colonizing bacteria, such as the opportunistic pathogen Pseudomonas aeruginosa, also carry structural homologs of eukaryotic A2Ms. Two types of bacterial A2Ms have been identified: Type I, much like the eukaryotic form, displays a conserved thioester that is essential for protease targeting, and Type II, which lacks the thioester and to date has been poorly studied despite its ubiquitous presence in Gram-negatives. Here we show that MagD, the Type II A2M from P. aeruginosa that is expressed within the six-gene mag operon, specifically traps a target protease despite the absence of the thioester motif, comforting its role in protease inhibition. In addition, analytical ultracentrifugation and small angle scattering show that MagD forms higher order complexes with proteins expressed in the same operon (MagA, MagB, and MagF), with MagB playing the key stabilization role. A P. aeruginosa strain lacking magB cannot stably maintain MagD in the bacterial periplasm, engendering complex disruption. This suggests a regulated mechanism of Mag complex formation and stabilization that is potentially common to numerous Gram-negative organisms, and that plays a role in periplasm protection from proteases during infection or colonization.

Identification and characterization of serine protease inhibitors in a parasitic wasp, Pteromalus puparum

Serine protease inhibitors (SPIs) regulate protease-mediated activities by inactivating their cognate proteinases, and are involved in multiple physiological processes. SPIs have been extensively studied in vertebrates and invertebrates; however, little SPI information is available in parasitoids. Herein, we identified 57 SPI genes in total through the genome of a parasitoid wasp, Pteromalus puparum. Gene structure analyses revealed that these SPIs contain 7 SPI domains. Depending on their mode of action, these SPIs can be categorized into serpins, canonical inhibitors and alpha-2-macroglobulins (A2Ms). For serpins and canonical inhibitors, we predicted their putative inhibitory activities to trypsin/chymotrypsin/elastase-like enzymes based on the amino acids in cleaved reactive sites. Sequence alignment and phylogenetic tree indicated that some serpins similar to known functional inhibitory serpins may participate in immune responses. Transcriptome analysis also showed some canonical SPI genes displayed distinct expression patterns in the venom gland and this was confirmed by quantitative real-time PCR (qPCR) analysis, suggesting their specific physiological functions as venom proteins in suppressing host immune responses. The study provides valuable information to clarify the functions of SPIs in digestion, development, reproduction and innate immunity.

Rapid Progression of Chronic Hepatitis C Virus Infection Following Treatment Failure With Harvoni: A Case Report

Patient is a 71-year-old African American male with medical history of hepatitis C virus infection S/P failed Harvoni therapy, hypertension, diabetes mellitus type II, chronic kidney disease stage IV, nicotine dependence and marijuana use. Was diagnosed of HCV infection about 16 years prior treatment was initiated. Treatment for Hepatitis C with Harvoni was started on (2/20/16) and completed 12 week course treatment with about 96% compliance. Following treatment patient HCV viral load became undetectable. 6-month post treatment HCV was detected with associated NS5A drug resistance. Patient remained asymptomatic except for fatigue that started during Harvoni treatment. Patient presented to the emergency department with pain was described has dull, located in the epigastric area, non-radiating, no known aggravating factor, relieved with pain medications, associated with loss of appetite, weight loss and constipation. On examination patient was cachetic, jaundiced, no asterixis, normal cardiovascular and decrease breath sounds in the lower lung zones worse on the right, tender hepatomegaly. Laboratory test result include Hepatitis C genotype 1a, fibrosis score 0.41, F, fibrosis stage F1-F2, necroinflammation A1-A2, Alpha 2-Macroglobulins 370mg/dL(high). Resistance test showed no RAV (Resistance associated variant) for NS5B but possible RAV to NS5A1. Hepatitis Be core Ab Positive, Hepatitis B surface Ab non-reactive, Hep A ab Neg, AFB Serum, Tumor Marker (3.3ng/Ml). CT abdomen pelvis showed heterogeneous liver mass with portal vein tumor thrombus, favoring hepatocellular carcinoma. Patient underwent Liver and lung biopsy which confirmed Hepatocellular carcinoma and squamous cell carcinoma of the lungs. Patient was started on palliative radiotherapy but died; primary cause of death respiratory failure and sepsis. Various factors have been associated with chronicity and probably progression to liver cirrhosis and hepatocellular cancer. Progression is variable with no linear relationship. Risk factors include old age, male gender, coinfection with hepatitis B, metabolic factor (obesity, insulin resistance, steatosis), use of alcohol, use of Marijuana, use of coffee and HCV genotype 3A. Other risk factors include duration of disease and being of African American descent. Studies have shown higher SVR, as high has 99% to 100% in patients treated for 24 weeks. Patients with multiple risk factors are likely to benefit from longer course of treatment.Figure

Structure of a bacterial α2-macroglobulin reveals mimicry of eukaryotic innate immunity

Alpha-2-macroglobulins (A2Ms) are plasma proteins that trap and inhibit a broad range of proteases and are major components of the eukaryotic innate immune system. Surprisingly, A2M-like proteins were identified in pathogenically invasive bacteria and species that colonize higher eukaryotes. Bacterial A2Ms are located in the periplasm where they are believed to provide protection to the cell by trapping external proteases through a covalent interaction with an activated thioester. Here we report the crystal structures and characterization of Salmonella enterica ser. Typhimurium A2M in different states of thioester activation. The structures reveal thirteen domains whose arrangement displays high similarity to proteins involved in eukaryotic immune defence. A structural lock mechanism maintains the stability of the buried thioester, a requirement for its protease-trapping activity. These findings indicate that bacteria have developed a rudimentary innate immune system whose mechanism mimics that of eukaryotes.

Influence of domestication process on immune response to repeated emersion stressors in Eurasian perch (Perca fluviatilis, L.)

Domestication might be a possible way to reduce the physiological response to long-term stressors and deleterious effects on immunity. The present study aimed to evaluate the chronic immune response induced by repeated emersions and the possible impact of domestication by comparing farmed Eurasian perch with short (F1) and long (F4) captive-life history. In the first experiment, fish were exposed to a single emersion and physiological stress response was measured in the short term to characterize fish sensitivity to the tested stressor. Serum cortisol and glucose elevated within 6h post-stress and splenosomatic index (SSI) decreased within 48h, indicating that the species was affected by emersion stressor. In the second experiment, F1 and F4 generations were submitted to repeated water emersions (3 times/week during 44days). On day 9, 18 and 44, samplings were performed 48h post-stressor to highlight any sustained disruption of immune system. Serum cortisol, glucose, SSI and lysozyme activity were evaluated and serum proteome was analyzed using 2D-DIGE. Any of the tested variables were affected by repeated emersions and proteomic analysis only revealed that alpha-2 macroglobulins (a2Ms) were up-regulated in the serum of stressed individuals. Domestication also resulted in the up-regulation of five a2M isoforms and down-regulation of complement C3 and Ig light chain proteins, independently of any stressor exposure. In conclusion, the results suggested that repeated emersions are not severe stressors for Eurasian perch, probably explaining why domestication had no influence on fish responses. Changes associated with domestication are highly complex and certainly need further investigations.

Functions of alpha 2 macroglobulins in pregnancy

The alpha 2 macroglobulins (A2M) are a family of abundant plasma proteins produced predominantly by the mammalian liver. Pregnancy zone proteins (PZP) of humans and rats are A2M family members that bind a wide variety of macromolecules including the important pregnancy-associated molecules such as vascular endothelial growth factor, placenta growth factor and glycodelin (also called PP14). Recently, a mouse gene analogous to PZP (A2M of pregnancy or A2Mp) was cloned. A2Mp has a unique pattern of expression in reproductive and cardiovascular tissues and, unexpectedly, is not expressed by liver. Since changes in heart function and remodeling of renal and uterine vasculature are amongst the earliest maternal responses to pregnancy, the product of the A2Mp gene has been postulated to systemically regulate these changes. A2Ms with and without non-covalently bound ligands also down regulate immune cell activation but promote immune cell migration, additional features associated with gestational success. Here, we review the A2M gene families of mice and humans, the predicted structural relationships between A2M and its pregnancy induced forms and the postulated roles for this gene family in normal pregnancy.

Cloning and sequencing of cDNAs encoding plasma alpha-macroglobulin and murinoglobulin from guinea pig: implications for molecular evolution of alpha-macroglobulin family.

Several clones encoding plasma alpha-macroglobulin and murinoglobulin were isolated from guinea pig liver cDNA library and sequenced. The clones for alpha-macroglobulin contained overlapping sequences which together spanned a stretch of 4,546 nucleotides with one open reading frame coding for 1,476 amino acid residues. The clones for murinoglobulin contained overlapping sequences which together spanned a stretch of 4,578 nucleotides with one open reading frame coding for 1,464 amino acid residues. The phylogenetic analyses of 11 proteins of the alpha-macroglobulin family revealed that the mammalian tetrameric alpha-macroglobulins consist of two main branches: alpha M-1 subfamily (rat alpha 1- and mouse alpha-macroglobulins) and alpha M-2 subfamily (human alpha 2-, rat alpha 2-, and guinea pig alpha-macroglobulins). This dichotomy is in good accordance with their immunological, chemical, and physicochemical properties, and indicates that guinea pig alpha-macroglobulin is orthologous to human and rat alpha 2-macroglobulins but paralogous to rat alpha 1- and mouse alpha-macroglobulins. The divergence of the two subfamilies was a phylogenetically ancient event which occurred around the separation of metatherians and eutherians. The genes of the two subfamilies have been maintained in the rat, but either one became extinct in the mouse, guinea pig, or human. The tree also shows that guinea pig murinoglobulin forms one clade with mouse and rat murinoglobulins (alpha 1-inhibitor 3) prior to joining the alpha M-2 lineage, and suggests that murinoglobulin is not a primitive form of tetrameric alpha-macroglobulin, but rather has evolved under selective pressure which is different from that of the tetrameric paralogues.

Characterization of the acute phase serum protein response in pigs.

Acute inflammation was induced in pigs using a single subcutaneous turpentine injection. The acute phase serum protein response was analyzed using crossed immunoelectrophoresis and immunodiffusion. The concentration of C reactive protein and haptoglobin increases 5-7 times 48 h after the injection, whereas the concentration of an alpha 2-globulin, named pig major acute phase protein (pig-MAP), increases at least 15-fold. A molecular mass of 115 kDa for pig-MAP was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This protein did not crossreact with antisera to human hemopexin, ceruloplasmin, H-kininogen and complement factor C3. Albumin and alpha-lipoprotein were negative acute phase proteins because their concentration significantly decreased during inflammation. Finally, the concentration of alpha 1-acid glycoprotein, fetuin, alpha 1-protease inhibitor, transferrin and alpha 2-macroglobulins, as well as total proteins, did not change significantly during inflammation.

Basis for the potent inhibition of influenza virus infection by equine and guinea pig α2-macroglobulin

Abstract The unique properties of equine and guinea pig sera which make them potent inhibitors of influenza virus adsorption and infection have been investigated. The inhibitory activities of both sera are found to reside entirely in their respective alpha 2-macroglobulins, high molecular weight glycoproteins which bind to viral hemagglutinins via sialic acids of their N-linked carbohydrate groups. Structure analysis has shown that both proteins contain 4-O-acetyl-N-acetylneuraminic acid (4-O-Ac-NeuAc) (Hanaoka, K., Pritchett, T. J., Takasaki, S., Kochibe, N., Sabesan, S., Paulson, J.C., and Kobata, A. (1989) J. Biol. Chem. 264, 9842-9849). These 4-O-acetylated sialic acids have been found in few species, making their coincidence with high inhibitory potency in equine and guinea pig alpha 2-macroglobulin striking. However, 4-O-Ac-NeuAc does not appear to increase the avidity of interaction with influenza virus since isolated oligosaccharides of equine alpha 2-macroglobulin are no more potent inhibitors of adsorption than isolated oligosaccharides of human alpha 2-macroglobulin, which is a relatively poor inhibitor and contains only NeuAc. Since 4-O-Ac-NeuAc is resistant to cleavage by viral sialidase it may serve to protect the inhibitor from inactivation. These and supporting results suggest that the key property of equine and guinea pig alpha 2-macroglobulin which make them high potency inhibitors is a spatial arrangement of sialic acid containing oligosaccharide groups which allows optimal interaction with multiple hemagglutinins. The implications of these results for the design of low molecular weight inhibitors of influenza virus infection are discussed.

α2-macroglobulin traps a proteinase in the midregion of its arms: An immunoelectron microscopic study

Abstract alpha 2-Macroglobulin, one of the major plasma proteinase inhibitors with Mr = 720,000, is known to inhibit proteinases of all four classes through the (Barrett, A. J., and Starkey, P. M. (1973) Biochem. J. 133, 709-724), but the proteinase binding site of alpha 2-macroglobulin has not been identified precisely. We localized bound proteinase molecules on the electron microscopic images of alpha 2-macroglobulin, using anti-proteinase IgG. Serratial Mr = 56,000 proteinase produced by Serratia marcescens was chosen as the antigenic probe in this study because its affinity to specific antibodies was retained in its bound state to alpha 2-macroglobulin. Dimers of alpha 2-macroglobulin/Mr = 56,000 proteinase complexes cross-linked with anti-Mr = 56,000 proteinase IgG were prepared and subjected to electron microscopic observations. The electron microscopic image of alpha 2-macroglobulin complexed with Mr = 56,000 proteinase had four straight arms with an overall shape looking like the character H. From the way anti-Mr = 56,000 proteinase IgG linked two alpha 2-macroglobulins, it was concluded that the proteinase existed in the midregion of one of the arms. This result helps us to form a more concrete view of the trap mechanism in that one of the arms of alpha 2-macroglobulin wraps the trapped proteinase and holds it isolated from high molecular weight substrates in the surrounding medium.

A functional, thioester-containing alpha 2-macroglobulin homologue isolated from the hemolymph of the American lobster (Homarus americanus).

An alpha 2-macroglobulin-like protease inhibitor was isolated from the cell-free hemolymph of the american lobster (Homarus americanus) by ion-exchange chromatography and gel filtration. Whereas the undissociated molecule has a molecular weight of 342,000 as determined by ultracentrifugation studies, under reducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the protein has a subunit molecular weight of 180,000. On the basis of this and other evidence, we conclude that the lobster protein is a dimer consisting of two disulfide-bonded monomers. The purified protein inhibits proteolytic enzymes but protects the esterolytic activity of trypsin toward low molecular weight substrates from inactivation by soybean trypsin inhibitor. The methylamine sensitivity of this activity suggests the presence of an internal thioester bond. This was confirmed by the covalent incorporation of [14C]methylamine, by the formation of Mr 55,000 and 125,000 autolytic cleavage fragments in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and, more directly, by the amino acid sequence of a tryptic peptide containing the putative thioester region. Whereas the N-terminal amino acid sequence (22 residues) of the protein revealed an overall identity of only 18% when compared with the human protein, the sequence of the thioester-containing peptide was highly conserved, both with respect to human alpha 2-macroglobulin and to other proteins having a thioester bond. The protein showed the "slow to fast" conformational change typical in alpha 2-macroglobulins in nondenaturing gel electrophoresis after treatment with trypsin, but not after incubation with methylamine.

THE ELASTASE INHIBITORS OF SWINE SERUM: AN IMPROVED METHOD FOR THE ISOLATION OF α2-MACROGLOBULIN

A previous communication from this laboratory as well as one from another described the separation of alpha 2-macroglobulin from swine serum. The products from both laboratories contained, in addition to alpha 2-macroglobulin, an additional macroglobulin contaminant with alpha 2-globulin mobility. Due to their physicochemical similarity these macroglobulins are not resolved using conventional column procedures such as ion exchange chromatography and gel filtration. Subsequent experiments have shown that immunoelectrophoretically pure swine alpha 2-macroglobulin is present, in good yield (65%) in the breakthrough effluent of columns of Bio-Gel A-1.5m-Reactive Blue 2 while the contaminating macroglobulin is tightly bound. The production of highly purified swine alpha 2-macroglobulin utilizing this observation is the subject of the present report. The product of the separation was found to be homogeneous when subjected to immunoelectrophoresis, at a concentration of 14-16 mg/ml, and diffused against antiswine whole serum antibody. The production of monospecific antibody, a more stringent test for homogeneity, resulted when the purified alpha 2-macroglobulin was injected into rabbits. Physicochemical analyses on the purified product showed that swine and human alpha 2-macroglobulins are true homologs.

Proteinase Inhibitors in the Gastrointestinal Tract, Pancreas and Liver during Fetal and Postnatal Development of the Pig

The occurrence and types of proteinase inhibitors were studied in the digestive system during the fetal and postnatal development of the pig. The protein concentration, the total trypsin-inhibiting capacity and the levels of the individual proteinase inhibitors, alpha 2-macroglobulin f (alpha 2Mf), alpha 2-macroglobulin s (alpha 2Ms), alpha 1-protease inhibitor (alpha 1PI) and alpha 2-antitrypsin (alpha 2AT) quantified by using electroimmunoassay, were assayed in stomach and intestinal contents, in homogenates of the stomach and intestinal mucosa, and in the pancreas and liver. The results showed that during porcine ontogeny high amounts of proteinase inhibitors are present in the digestive system. During the fetal period, the most outstanding characteristic was the high levels of alpha 1PI and alpha 2AT, in contrast to the low levels of the alpha 2-macroglobulins. Furthermore, the trypsin-inhibiting capacity and the levels of alpha 1PI and alpha 2AT showed in most cases a statistically significant decrease during the fetal period (12-36 cm crown-to-rump length). In the neonatal period, 0-96 h after birth, the levels of the individual inhibitors were rather constant, but a significant decrease to low levels of both trypsin inhibition and the individual inhibitors was observed in the adult pig. Trypsin activity was found in approximately half of the pancreas homogenates from the late fetal period and in newborn pigs before they began to suckle. The physiological function of the proteinase inhibitors observed in the digestive system during porcine ontogeny is probably to protect against precocious proteolytic degradation by the formation of inactive enzyme/inhibitor complexes.

An α2‐macroglobulinlike activity in the blood of chelicerate and mandibulate arthropods

The alpha 2-macroglobulins are large molecular weight proteinase-binding proteins that inhibit the ability of proteinases to hydrolyze protein substrates without suppressing activity against amide or ester substrates. They are also able to protect the active site of bound proteinases from active site inhibitors of suitably high molecular weight. The ability to protect the amidolytic activity of trypsin from the macromolecular active site inhibitor, soybean trypsin inhibitor, was used to demonstrate an alpha 2-macroglobulinlike activity in the blood of the horseshoe crab, Limulus polyphemus and the crustaceans Libinia emarginata (the spider crab) and Cancer borealis (the Jonah crab). The alpha 2-macroglobulinlike activities of L. polyphemus and L. emarginata are sensitive to methylamine, but that of C. borealis is relatively insensitive. The molecular weights (mw) of the trypsin-protecting proteins in L. emarginata and C. borealis, estimated from gelfiltration studies, are, respectively, 480 X 10(3) and 460 X 10(3), and are significantly smaller than that of L. polyphemus (Mr = 570 X 10(3)).

Immunochemical identification of ferritin and its immunologic analogs ?-fetoprotein and ?2H-globulin

Immunochemistry techniques were made use of to identify the immunological analogs of ferritin - beta-fetoprotein and alpha 2H-globulin. Direct correlation of the test systems for ferritin, beta-fetoprotein and alpha-globulin demonstrated their complete identity. Electrophoretic mobility of beta-fetoprotein was found to be identical to that of ferritin, corresponding with blood serum alpha 2-globulins. alpha 2H-Globulin was obtained from human kidney tumors according to the method devised by the author. The glycoprotein component of alpha 2H-globulin isolated from the preparation alpha 2H-globulin did not prove identical to kidney tumor ferritin and was thus signed to serum alpha 2-macroglobulins of healthy subjects. Since there are no differences between ferritin and its immunological analogs, it is suggested that beta-fetoprotein and alpha 2H-globulin be termed ferritin.

The separation of alpha-2 macroglobulin into five components with differing electrophoretic and enzyme-binding properties.

The alpha-2 macroglobulins from human serum and plasma were isolated by Bio-Gel P-300 and A5m gel filtration. The material showed a single peak on sedimentation velocity ultracentrifugation, a mol wt of 650,000 by sedimentation equilibrium ultracentrifugation, and a major precipitin arc in the alpha-2 macroglobulin region by immunoelectrophoresis against whole human serum. Two bands were observed in the alpha-2 macroglobulin region when acrylamide gel electrophoresis was performed with a pH 8.9 running gel. When a pH 7.8 gel was used, five electrophoretic species were observed. In both cases, the preaddition of stoichiometric amounts of trypsin or chymotrypsin added to alpha-2 macroglobulin resulted in disappearance of slower bands leaving only one band on acrylamide gel electrophoresis patterns. Preparative acrylamide gel electrophoresis separated alpha-2 macroglobulin obtained from Bio-Gel into five closely-spaced species. Separation was sufficiently adequate to show that those species of alpha-2 macroglobulin which bound trypsin and chymotrypsin were represented by slower moving species and that the fastest moving material had lost virtually all of the ability to bind these enzymes. Preparative acrylamide gel electrophoresis of a mixture of alpha-2 macroglobulin-trypsin complex and alpha-2 macroglobulin revealed that the fast moving component was alpha-2 macroglobulin-trypsin complex and that the slower moving material was unbound alpha-2 macroglobulin. The naturally occurring amidase activity of the alpha-2 macroglobulin using benzoylarginine-p-nitroanilide (BAPNA) as substrate was investigated and unlike its trypsin-binding activity, amidase activity was found to be of the same specific activity in all electrophoretic fractions. Binding of trypsin and chymotrypsin to alpha-2 macroglobulin revealed that alpha-2 macroglobulin maximally bound 2 moles of trypsin and 1 mole of chymotrypsin. When the enzymes were added simultaneously there was competition. Chymotrypsin added to alpha-2 macroglobulin before the addition of trypsin prevented all trypsin binding even though only one site was filled with chymotrypsin. These results were explained by the acrylamide gels which showed that 1 mole of chymotrypsin was sufficient to convert all the alpha-2 macroglobulin to a species with the fastest mobility which no longer binds additional enzyme.

MACROGLOBULINEMIA AND STEATORRHEA: ROENTGEN AND PATHOLOGIC FINDINGS IN THE INTESTINAL TRACT

Macroglobulins are globulins of high molecular weight having a sedimentation constant of 19S. Immunoelectrophoresis differentiates gamma globulins into five components of specific antigenicity, designated IgG, IgA, IgM, IgD, and IgE. The IgM or macroglobulin fraction constitutes approximately 5 to 10 per cent of the total serum antibodies (40 to 260 mg. per 100 ml. of serum, average 90 to 100 mg.). In addition to IgM globulin, normal human serum contains alpha-2 macroglobulins, whose function is not known. Most human serum antibodies to lipopolysaccharide antigens are IgM globulins.1, 24, 27, 33, 34

Differences in serological properties of macroglobulins from cancer and normal sera.

Studies on the alpha-2 macroglobulins isolated from the sera of patients with various types of cancer and from the sera of healthy individuals revealed definite serological differences between the two groups of fractions. These differences relate to flocculation of bentonite particles, reaction with coelomic fluid substance, and precipitin reactions with anti-alpha-2 sera.

Immunoelectrophoretic Analysis of Serum Proteins of Patients with Malignant Tumors

Immunoelectrophoretic changes in the serum of 32 patients with various type of malignant tumors, were studied. The method described by Grabar and Burtin was used. The following results were obtained: Albumin: The line of precipitation was in all cases more curved, less intensive and generally shortened; Alpha-1 globulin: The curves found were well visible and symmetrical in both pathological and control sera; Alpha-2 globulin: The line of alpha-2 macroglo-bulins was always present and best marked; Beta-1 globulin: Always well visible the line of siderophyllin. Under this line, in 14 out of 32 cases, a line, which is presumably beta-1/A globulin, was found; Beta-2 globulin: In half of the cases the line of beta-2/M was well visible; Gamma-globulin: No changes were found. The changes found are believed to be related to the reaction of normal, serum proteins producing cells to the presence of malignant tumors.

Hypoalbuminemia (with anasarca) due to hypercatabolism, serum protein exudation into the gastrointestinal tract, increased capillary permeability and hypoanabolism: The unusual occurrence of increased capillary permeability temporarily reversed by human growth hormone therapy

1. 1. A fifty-nine year old white man presented with a two and a half year history of unremitting hypoproteinemia and anasarca (idiopathic hypoproteinemia). 2. 2. Hypoalbuminemia, as revealed by album-I 131 turnover studies, may have resulted from at least four abnormal physiologic mechanisms: (a) hypercatabolism, as reflected by an increase in the fractional rate of catabolism; (b) exudation of albumin and other plasma proteins into the stomach, duodenum and jejunum, resulting in an increased stool nitrogen; (c) hypoanabolism of albumin without any other known biochemical abnormalities of hepatic parenchymal function; and (d) increased peripheral capillary permeability resulting in the distribution of an unusually large percentage of the total exchangeable albumin pool in the extravascular compartment. 3. 3. The hypoproteinemia involved not only albumin but also iron-binding globulin and ceruloplasmin. 4. 4. There were increased concentrations of serum lipoproteins, as reflected by an elevation of serum cholesterol, and of alpha 2-macroglobulins. The concentration of serum cholesterol varied inversely with the serum albumin concentration, decreasing toward normal levels as the albumin level increased toward normal levels. 5. 5. The increased peripheral capillary permeability was transiently reversed by the administration of human growth hormone. 6. 6. Adrenal cortical hyperactivity was present, reflected by an increased concentration and rate of synthesis of hydrocortisone, high urinary excretion of aldosterone, and adrenal cortical hyperplasia. The increased adrenocortical activity may have played a contributory role in enhancing the increased fractional catabolic rate of albumin and the severity of the patient's massive edema.