Levels Of Glycolipids Research Articles

Control of kidney size by sex hormones: possible involvement of glucosylceramide

Because androgenic hormones produce an increase in kidney size and the production of kidney glycosphingolipids and because the level of tissue glucosylceramide (GlcCer) has been implicated as a modulator of organ size, we measured the activities of two enzymes in mouse kidney that (in part) determine the level of this glycolipid. GlcCer synthase was found to rise in specific activity with age and increased kidney size, whereas GlcCer glucosidase was found to decrease with age; both enzyme changes act to elevate the level of kidney GlcCer and point to the level of this lipid as a determinant of kidney size. The increase in synthase was especially rapid in male kidney, consistent with the more rapid growth of male kidney. Testosterone injection into both males and females produced elevated levels of GlcCer synthase, decreased levels of the hydrolase, and more rapid growth. Injection of 17 beta-estradiol, which produced slow or negative kidney growth, caused the synthase activity to decrease in female mouse kidney and the glucosidase activity to rise in both sexes. Thus the changes in kidney size produced by the two hormones paralleled the changes in GlcCer level predicted by the hormone effects on the two enzymes. In liver, estradiol produced increases in both enzymes but only the male liver increased in size. Testosterone did not affect the liver. The testes grew with age but the activities of both enzymes decreased.

Lipid Changes in Maize Seedlings in Response to Field Water Deficits

Maize seedlings (?ea mays Hybrid r i Montano; were grown under neid irrigation and dryland conditions, stress was imposed i ? d after planting by witholding water for 8 d, and seedlings were harvested for analysis 20 d after planting. In comparison to the control, leaf water potential drops from -0-65 to -103 MPa and water saturation deficit increases by 40%, but plant height does not show a significant reduction. The fresh and dry weights of stressed seedlings and their ratio decrease. The total lipid and total lipid phosphorus contents of seedlings exposed to dryland conditions decrease by about 43% and 71%, respectively, in comparison to the contents of the watered seedlings. The diacylglycerol, free fatty acid and total polar lipid contents decrease significantly with stress, but in the latter class the dryland conditions induce a decrease of more than 50% in phospholipid levels, whereas they do not cause any change in glycolipid levels; on the contrary, the triacylglycerol amount increases by about 30% over the control. Notwithstanding differences found in the fatty acid composition of the various lipid classes and between treatments, the degree of unsaturation never changes significantly either in the control or in the stressed seedlings. Under stress conditions, free sterol levels increase without showing any change in the ratio of 'more planar' to 'less planar' sterol. The increase in free sterols and the decrease in phospholipid levels under water deficit conditions raise the sterol/phospholipid molar ratio 3-fold. The different responses of the lipid classes to water deficits and their possible significance are discussed.

Lipid profiles of conidia of Aspergillus niger and a fatty acid auxotroph

Conidial lipids of the wild-type (V35) Aspergillus niger and its unsaturated fatty acid auxotroph (UFA2) were compared. The wild type contained lower levels (7.6%) of phospholipids and higher levels (28.4%) of glycolipids than the mutant (16.5 and 22.2%, respectively). Oleic (33.4%), linoleic (22.5%), palmitic (12.8%), stearic (7.4%), and linolenic (6.2%) were the main fatty acids of the wild type (V35). The mutant grew only in the presence of unsaturated fatty acid having at least one delta 9cis double bond, and its conidial fatty acid profile was influenced by the exogenous acid. Analyses of the fatty acids of UFA2 grown in the presence of different fatty acid supplements support the original view that the mutant is defective in delta 9-desaturase activity.

Isolation and characterization of two types of MDCK epithelial cell clones based on glycosphingolipid pattern

The Madin-Darby canine kidney (MDCK) epithelial cell line was shown previously to be heterogeneous with marked differences reported between low-passage (strain I) and high-passage (strain II) cultures (Richardson, J.C.W., Scalera, V. and Simmons, N.L. (1981) Biochim. Biophys. Acta 673, 26–36). This report describes major differences in the glycolipids of the two subpopulations of cells that comprise strain I and strain II cultures. The majority of strain II cells were strongly positive for the Forssman glycolipid antigen, while strain I cells were Forssman-deficient. Upon finding that strain I cells were contaminated with mycoplasma, we rescued Forssman-deficient cells from strain II using an anti-Forssman plus complement lysis procedure. Clones of surviving cells consisted of two distinct cell types. The first were Forssman-deficient, non-ciliated, spindle-shaped cells which generated negative (apical to basolateral) transepithelial potential differences. Clones of the second type were strongly Forssman-positive, ciliated, and formed island-shaped clusters of cuboidal cells. These latter clones generated positive potential differences and grew more slowly than the spindle-shaped clones. Spindle cells were enriched in fucolipids, while cuboidal cells contained higher levels of sulfated glycolipids. These two types of clones should provide excellent model systems in which to study the processing and polarity of glycolipids in epithelial cells.

Regulation of renal sulfoglycolipid biosynthesis

The in vitro activity of the renal galactolipid sulfotransferase and the level of sulfated glycolipids in the rat kidney have been correlated as a function of age. The galactolipid sulfotransferase was found to be greatly reduced in the young as compared with the adult animal. The relatively minor changes in the sulfated glycolipid content of the kidney with age suggests that an increase in sulfoglycolipid turnover occurs during growth. An inhibitory activity was detected in the homogenate supernate of the young animal capable of reducing the in vitro sulfotransferase activity of the adult. Assay of the human renal galactolipid sulfotransferase showed that this enzyme activity is deleted in samples of the blastematous form of Wilm's renal tumor. The results suggest that the rate of synthesis of renal sulfoglycolipids may prove a marker of renal development, perhaps by post translational regulation.

Effect of Frost Hardening on Lipid and Fatty Acid Composition of Chloroplast Thylakoid Membranes in Two Wheat Varieties of Contrasting Hardiness

Lipid and fatty acid composition of chloroplast thylakoid membranes was determined in two varieties of wheat (Triticum aestivum L.), the hardy Miranovskaja and the sensitive Penjamo. Plants were grown at room temperature or under frost hardening conditions (1.5 degrees C). Changes in lipid and fatty acid composition of the isolated thylakoids could be related to the temperature dependence of light-stimulated proton uptake. Changes in the thylakoid phospholipids upon hardening of the two varieties did not show any direct relation with low temperature tolerance of light-dependent H(+) uptake; neither did changes in phospholipid fatty acid chain lengthening to 20 and 22 C-atoms in combination with increased desaturation up to 6 double bonds. Increased low temperature tolerance of light-induced H(+) uptake by hardening was correlated with the following glycolipid changes: maintained glycolipid level, a proportionally increased digalactosyl diglyceride fraction, a decrease in thylakoid monogalactosyl diglyceride, increased sulfolipid fatty acid chain lengthening (20 and 22 C-atoms), and increased sulfolipid desaturation (4-6 double bonds). We suggest that the above mentioned changes in glycolipids have adaptive value for low temperature tolerance of light-dependent proton uptake.

809 GM3 GANGLIOSIDOSIS: RE-CLASSIFICATION AS AN X-LINKED DYSHISTOGENETIC SYNDROME OF UNKNOWN ETIOLOGY

A male infant cousin of a patient with “GM3 gangliosidosis” was born at 29 wks gestation to Jewish parents. The infant closely resembled his cousin with coarse facies, low hairline, low-set and posteriorly rotated ears, macroglossia, gingival hypertrophy, micragnathia, cleft palate, redundant nuchal skin, umbilical and inguinal hernias, mild hepatosplenomegaly, cryptorchidism, hypotonia then spasticity and seizures. Chromosome analysis, skeletal x-rays, bone marrow smear and urinary mucopolysaccharides, oligosaccharides, organic acids and aminoacids were normal. Measurement of multiple leukocyte lysosomal hydrolases showed normal activities. The patient died at 4 mons of age. At autopsy, the brain was small (473 g) and showed patchy demyelination, reactive gliosis, and glial and neuronal heterotopias throughout the CNS. Anomalous cerebellar extension around the ventral surface of the medulla was also present. The kidneys showed diffuse glomerulocystic disease with dilatation of Bowman's capsule. Biochemical analysis of brain showed decreased levels of myelin glycolipids. However, in contrast to the cousin with “GM3 gangliosidosis”, the concentration and pattern of brain gangliosides were normal. These findings, along with those reported from studies on a second, similarly affected, male cousin, indicate that the disease originally described as “GM3 gangliosidosis” should be re-classified as an X-linked dyshistogenetic syndrome of unknown etiology.

Free sterols and glycolipids in the aleurone tissue of germinating wheat

The action of gibberellic acid on wheat aleurone tissue led to reduced levels of free sterols and glycolipids compared with control tissue. Radio-labelled precursors were not incorporated into sterols or glycolipids, although mevalonate and glycerol were incorporated into polyisoprenoid hydrocarbon and phospholipid respectively. It is concluded that sterols and glycolipids are not synthesized in the tissue during germination; this is in contrast to earlier reports of the active, gibberellin-regulated metabolism of phospholipids.

Changes in nervous system glycolipids during metamorphosis of Xenopus laevis.

Qualitative and quantitative changes occurring in the myelin marker glycolipids, cerebrosides, sulfatides, and monogalactosyl diglyceride, in the nervous system (brain, spinal cord, and tail) of Xenopus laevis during its metamorphic stages were analyzed by normal and reverse-phase high performance liquid chromatography. The concentration of these glycolipids increased rapidly in brain until the tadpole reached the middle of metamorphosis, fluctuated slightly, decreased until metamorphosis was completed, and increased once more as the frog matured. Similar changes were observed in the spinal cord, but the decrease of glycolipids occurred at a later stage of metamorphosis. The glycolipid level in tail nerve reached a peak at the beginning of metamorphosis and then rapidly decreased. The ratios of hydroxycerebroside and hydroxysulfatide to respective nonhydroxylipids in brain, spinal cord, and tail remained constant throughout the metamorphic change but differed in each tissue. The tail contained the highest ratio. The glycolipids in sciatic nerve generated during the metamorphosis had an even higher hydroxyl lipid/nonhydroxy lipid ratio. The cerebrosides contained extremely high concentrations of monounsaturated fatty acids with very long carbon chains (C22-C25) and this homolog composition remained almost unchanged throughout metamorphosis. These results indicate that active degradation of these glycolipids, and probably of myelin, occurs but the glycolipid composition of myelin appears to remain the same throughout the metamorphic process. The significance of these findings is discussed from a morphological standpoint.

Characterization of some minor gangliosides in Tay—Sachs brains

The ganglioside distribution of Tay—Sachs brain was re-examined in detail. In both the gray and white matter, the levels of lipid-bound sialic acid were increased 6- and 10-fold, respectively, over normal infant brain, and approximately 90% of the total ganglioside was G M2. The level of G M2 was increased about 90 times in gray matter and 220 times in white matter in comparison with that in normal controls. The level of G D1a-GaINAc was increased 19 times and 10 times in gray and white matter, respectively. The concentration of G D2 was increased about 4-fold in Tay-S-Sachs white matter. In addition, the G M3 level was increased 2.7 and 3.5 times and the G D3 level 2 and 2.4 times over normal gray and white matter, respectively. However, the levels of other complex gangliosides such as G M1, G D1a, G D1b, G T1b and G Q1b decreased remarkably. Since G M2, G D2, G D1a-GalNAc and a recently characterized ganglioside G M1b-GalNAc possess a common N-acetylgalactosaminyl terminal structure, their accumulation in Tay—Sachs brains is therefore consistent with the known hexosaminidase A deficiency. However, the accumulation of hexosamine-free G M3 and G D3 is not. The in vitro incorporation of N-acetylgalactosamine into G M3 to form G M2 was examined in a rat brain microsomal fraction in the presence of large amounts of other glycolipids. Acidic glycolipids were slightly stimulating and then became increasingly inhibitory when the molar ratio of lipid to substrate G M3 exceeded 10 to 1. Neutral glycolipids and the phospholipid, phosphatidylcholine, were inhibitory at all levels tested. The data suggest that the accumulation of G M3 and G D3 in Tay—Sachs brains could be due to an inhibition of N-acetylgalactosaminyl-transferas by high levels of glycolipids, and the inhibition is not due to chelation of the obligate divalent cation necessary for the activity of this enzyme. The inhibition of this enzyme may also be responsible for the decreased levels of other complex gangliosides.

Lipids of gastric secretion in patients with cystic fibrosis

Lipids were investigated in gastric secretions of patients with cystic fibrosis and of normal individuals. Organic extracts from dialyzed and lyophilized samples were fractionated on silicic acid columns into neutral lipids, glycolipids and phospholipids. The lipids contained in each fraction were separated into individual components by thin-layer chromatography and quantitated. The gastric secretions of patients with cystic fibrosis contained 80–140% more lipids than those of normal individuals, exhibited an elevated level of neutral lipids and contained alkylglycerols and alkylacylglycerols. The level of glycolipids was higher in normal gastric secretions. The phospholipids of cystic fibrosis secretions exhibited about 50% lower content of lysophosphatidylcholine, lysophosphatidylethanolamine and lysophosphatidylserine. The glycosphingolipids of both types of samples contained mono-, di- and trihexosylceramides. The major glyceroglucolipid of normal gastric secretions was tetraglucosyl glyceroglucolipid, whereas hexa- and octaglucosyl glyceroglucolipids were predominant in cystic fibrosis samples. The sulfated glyceroglucolipids in cystic fibrosis samples were lower than those of normal secretions and represented only 4–37% of total glyceroglucolipid, whereas in normal secretion sulfated glyceroglucolipids averaged 50–62%.

Effects of divalent cations on the glycolipids from cultured mouse neuroblastoma cells.

The influence of divalent cations on glycosphingolipid metabolism was examined in the NB41A mouse neuroblastoma clonal cell line. HPLC methods were utilized to quantitate the effects on neutral glycolipids and monosialogangliosides. NB41A cells were shown to contain GM3, GM2, GM1, GD3, and GD1a by HPLC and TLC. The neutral glycosphingolipids consisted of glucosylceramide (GlcCer), lactosylceramide (LacCer), GalNAc (beta 1 leads to 4) Gal(beta 1 leads to 4)Glc(beta 1 leads to 1)Cer (GgOse3Cer), and GalNAc(beta 1 leads to 3)Gal(alpha 1 leads to 4) Gal(beta 1 leads to 4)Glc(beta 1 leads to 1)Cer (GbOse4Cer) according to their HPLC behavior. Cells grown in the presence of 1.85 mM-EGTA showed a two-to threefold increase in GM3 whereas other glycosphingolipids were only slightly affected. When cells were grown in the presence of 1.45 mM-EGTA plus 0.4 mM-EDTA a similar increase in GM3 was observed but this change was now accompanied by decreases in GM2, GM1, GgOse3Cer. The EGTA-EDTA effects were reversed when growth was in the presence of Ca2+ sufficient to bind all chelator. Mn2+ replacement reversed the chelator effects differentially; GM2 and GM1 levels were the most sensitive to increases in Mn2+ concentration; GgOse3Cer and GbOse4Cer were also sensitive, whereas GM3 was the least affected. These results suggest calcium serves an important regulatory role on GM3 levels and that manganese concentration may regulate the levels of galactosamine-containing glycolipids in mouse NB41A neuroblastoma cells.

Murine leukemia. Proposed role for gangliosides in immune suppression

Glycolipid-bound sialic acid levels were elevated 2 to 4-fold in the sera of two strains of mice bearing thymic lymphoma produced either spontaneously (AKR/J) or due to chemical carcinogenesis [Swiss mice injected with 5-(3,3-dimethyl-1-triazeno)imidazole-4-carboximide]. The serum glycolipid-bound sialic acid level reflected the tumor burden of the AKR/J mice during the early stages of leukemogenesis. Furthermore, the elevation was found to coincide with the ontogenesis of thymic lymphoma and not to be simply an age-dependent phenomenon. TLC analysis of Florisil column-purified gangliosides from the sera of AKR/J and Swiss mice suggested presence of gangliosides with mobilities very close to GM2 and GM3 standards respectively. On the premise that the elevated glycolipid levels in circulation might interfere with normal lymphocyte functions, the immunoinhibitory properties of exogenously added mixed gangliosides were examined on tests of in vitro correlates of the immune response. Gangliosides inhibited concanavalin A and lipopolysaccharide-induced [ 3 H]-thymidine, [ 14 C]-leucine and [ 3 H]-lysine uptake by normal AKR/J mouse thymocytes and spleen cells. Mixed gangliosides also suppressed the two-way mixed lymphocyte reaction of AKR/J × Swiss and AKR/J × DBA/2 spleen cells. These and other results strongly suggest a general immunologically relevant role for gangliosides in the ontogeny of thymic lymphoma of mice.

Serum la Levels During Tumor Growth in Mice and Humans23

Antigen stimulation in mice such as occurs with the rejection of an allogeneic tumor graft caused a substantial rise in serum glycolipid Ia levels. However, mice bearing a measurable syngeneic tumor had no detectable Ia antigens in their sera; this observation was made in several different strains of inbred mice with 5 different tumors. In each instance the serum Ia level fell as the tumor grew progressively, reached zero at about the time the tumor was visible, and remained at this zero level until the mouse died. Similar results were found in humans: Tumor-bearing patients had markedly suppressed serum Ia levels. The mechanism of the fall in serum Ia glycolipid levels is not known, but the measurement of the serum Ia glycolipid content appears to reflect the level of activation of the immune system, and the suppression of serum glycolipid Ia levels found in tumor-bearing mice and patients may have important clinical implications.

Lewis phenotype of erythrocytes and Leb-active glycolipid in serum of pregnant women.

In an attempt to provide an explanation for the previously reported effect of pregnancy on the Lewis phenotype of erythrocytes, the level of Leb-active glycolipid in serum was compared with the reactions of erythrocytes, using samples obtained from 73 nonpregnant women, 74 women at the time of delivery, and 2 women at weekly intervals during their pregnancy. In this Swedish population, the frequency of the Le(a--b-) blood group increased from 11% in nonpregnant women to 36% in women at the time of delivery. Among Le(a--b+) women of all ABO groups, those who were A1 most often became (Leb-) during pregnancy. The change in phenotype occurred as early as the 24th week of gestation; the Leb antigen was again detectable within 6 weeks after delivery. The concentration of Leb glycolipid in serum, as measured by radioimmunoassay, decreased only slightly during pregnancy. The repartition of glycolipids, secondary to the increased ratio of lipoprotein to red cell mass that occurs during pregnancy, may account for the relative lack of Lewis glycolipid on erythrocytes.

The distribution of acyl lipids in the germ, aleurone, starch and non‐starch endosperm of four wheat varieties

AbstractThe quantitative distribution of 23 classes of acyl lipids was determined in the germ, aleurone, starch and endosperm non‐starch fractions of Atou (Soft English), Flinor (Hard English), Waldron (US Hard Red Spring) and Edmore (US Amber Durum) wheats. All four wheats had similar proportions (dry basis) of pericarp (6.8–8.6%), germ (2.5–3.0%), starchy endosperm (78.7–84.5%) and starch (59.3–67.5%), and similar quantities of acyl lipids in the whole kernels (2.8–3.2%), germ (25.7–30.5%), starch (0.8–1.2%) and endosperm non‐starch fractions (0.8–1.1%). Flinor, Waldron and Edmore had 7.3–10% aleurone containing 8.7–10.6% lipids, but Atou appeared to have an abnormally low aleurone weight (4.0%) and a correspondingly high lipid content (19.4%). Pericarp acyl lipids were studied only in Atou, where they comprised 1.3% of the dry weight and 3.8% of the total acyl lipids in the whole kernel. Lipids in the germ and aleurone consisted of triglycerides (60.3–79.3%), other nonpolar lipids (5.6–12.0%) and phospholipids (13.6–17.9%). Starch lipids were almost exclusively lysophospholipids (89.4–94.4%). Greater variation was found in the endosperm non‐starch lipids which consisted of triglycerides (13.7–34.1%), other nonpolar lipids (33.2–48.5%), glycolipids (18.6–38.3%) and phospholipids (21.9–35.3%). Edmore had the highest levels of triglycerides and non‐polar lipids, and the lowest levels of glycolipids (as expected in a tetraploid wheat). Atouresembled Edmore in its low levels of steryl esters and glycolipids, but it also had least phospholipids.

Characteristics of transplantable tumors induced in the rat by N-2-fluorenylacetamide: elevations in tissue and serum sialic acid.

The correlation between levels of sialic acid and sialic acid-containing glycolipids (gangliosides) in tumors and serum with the growth characteristics of the tumors was investigated in transplantable hepatomas and squamous cell carcinomas initiated with the carcinogen N-2-fluorenylacetamide and propagated in vivo and in tissue culture. Tumor lines varied in histologic classification, growth rate, and ability to form pulmonary metastases. There was neither a correlation between growth rate and histologic classification nor between either of these two parameters and the ability to metastasize. Total and ganglioside sialic acid levels were elevated in carcinogen-treated liver and in transplantable hepatomas when contrasted with normal liver. Levels of sialic acid showed a weak correlation with the growth rate of hepatomas. Gangliosides from nonmetastatic hepatoma lines exhibited less N-acetylneuraminic acid--galactose--glucose-N--acylsphingosine (GM3) and an increased ratio of total monosialogangliosides to disialogangliosides than did metastatic lines. Ganglioside patterns of metastatic hepatoma lines more closely resembled the ganglioside patterns of normal liver than did those of the nonmetastatic lines. Concomitant elevations of total and ganglioside sialic acid levels were observed in sera of animals bearing subcutaneous implants. Serum levels of total sialic acid did correlate with total sialic acid levels found in the tumor tissues. The levels of serum sialic acid were not correlated directly with levels of serum sialyltransferase activity. Elevations of both tissue and serum ganglioside sialic acid were consistent features of liver tumorigenesis in the rat after N-2-fluorenylacetamide administration. They appeared, furthermore, to be early events not directly related to tumor cell differentiation or metastasis.

The effect of growth temperature on the lipids in an extremely thermoacidophilic bacterium, TA-1.

The extreme thermoacidophile TA-1, a Sulfolobus-like organism, was grown at temperatures ranging from 50 to 85°C (at 5°C intervals). The extracted cellular lipids were analysed qualitatively and quantitatively. At temperatures close to the optimum for growth, the levels of glycolipids in total lipid fractions increased. The phospholipid contents were constant except at extremely unfavorable tempertaures for the growth.The alkyl-chains of the total lipid were analysed as alkyl-halide derivatives by gas-liquid chromatography. Usually seven to eight peaks were detected on the chromatogram. By increasing the growth temperature, the areas of peaks which had longer retention periods increased, but those of the shorter ones decreased. These results suggest that the extreme thermoacidophile TA-1 has some mechanisms which alter the membrane properties by changing lipid compositions and their alkyl-chains.

Glycolipids in Histologically Human Different Lung Carcinoma Types<xref ref-type="fn" rid="FN2">2</xref><xref ref-type="fn" rid="FN3">3</xref>

Glycolipids were isolated from primary human lung carcinoma tissue of various histologic types: adenocarcinoma, squamous cell carcinoma, and undifferentiated small cell carcinoma. Each type of carcinoma had a characteristic glycolipid pattern. The major glycolipids isolated were ceramide monohexosides, ceramide dihexosides, ceramide trihexosides, globoside, and hematoside. Squamous cell carcinoma and undifferentiated small cell carcinoma showed marked increases of ceramide monohexosides and dihexosides. Adenocarcinoma had a much higher level of the sulfatide (ceramide 3-sulfate-galactoside) as compared to squamous cell carcinoma, undifferentiated small cell carcinoma, or normal lung tissue. Embryonic tissue had more significant levels of sulfatide than did the other carcinomas. Adenocarcinoma had significantly lower levels of glycolipids due mainly to a decrease in the amount of ceramide monohexosides and dihexosides and hematoside.

The effect of ethanol on the constituents of the gastric mucous barrier

The effect of ethanol on the gastric ‘mucous barrier’ and gastric mucosal constituents was investigated. Deranged gastric secretions were obtained by perfusion in vivo of Ghosh-Lai rat stomachs with 10%, 15% and 20% ethanol in saline. The content of protein, immunoreactive albumin and haemoglobin were determined on native perfusates. Lipids were extracted from dialysed and lyophilized samples of ethanol perfusates and saline controls, separated into individual components by means of two-dimensional thin-layer chromatography, and compared. The content and composition of protein bound carbohydrates was determined on the insoluble residues after lipid extraction. Significant increments in the level of glycolipids (glyceroglucolipids), cholesterol esters, glycerides, protein, immunoreactive albumin, and protein bound carbohydrates were found in the ethanol perfusates. Six times greater quantities of glycolipids, proteins and immunoreactive albumins were found in 20% ethanol perfusates as compared to saline controls. Also, a ten fold increase of protein bound carbohydrates and neutral glycerides, and an 18 fold increase of cholesterol esters in 20% ethanol perfusates were detected. The glycolipid fractions consisted of neutral and sulphated glyceroglucolipids. The saline and 10%, 15% and 20% ethanol perfusates were devoid of phospholipids and glycosphingolipids. The data shown indicate that the presence of ethanol in the stomach causes depletion of the mucous barrier and leakage of serum proteins into the gastric lumen. From the absence of phospholipids and glycosphingolipids in the perfusates one may infer that the gastric epithelial membranes and vascular membranes remained intact. Also, the data presented indicate that the mucous barrier contains glycoproteins and considerable quantities of lipids of which glyceroglucolipids are the most prominent components, but in which phospholipids and glycosphingolipids are not present.