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G Ailhaud

Publications and source records attributed to G Ailhaud.

At least 181 records · Page 10Linked to original sources
PubMed1977

Glycerol-ester hydrolase from human small intestine and its possible role in the degradation of neutral lipids.

A glycerol-ester hydrolase has been characterized and partially purified (23-fold) from human small intestine. A pancreatic origin was excluded through the use of an immunoserum directed against human pancreatic juice, while a pharyngeal (gastric) origin was unlikely owing to the optimum pH range of activity of the gastric enzyme as compared to that of the intestinal enzyme. The glycerol-ester hydrolase is mainly active toward short- and medium-chain di- and triglycerides and toward micellar long-chain monoglycerides. A role in the absorption of neutral lipids, mainly in pathological situations, is postulated.

Bile Acids and Salts↗
PubMed1976

Uptake and metabolism of fatty acids and analogues by cultured cardiac cells from chick embryo.

Cultured heart cells from chick embryo, present as a confluent monolayer in a minimal medium, take up labelled fatty acids (from C6 to C22) bound to serum albumin with a rapid incorporation into neutral and complex lipids (visible at 15 s), while beta-oxidation is delayed (visible at 15 min). Fatty acids enter the cardiac cells through two mechanisms, one involving a readily saturable process, the other resembling passive diffusion. The saturable transport system recognizes fatty acids with a high affinity, Km from 4.5 to 16 muM. The V is from 0.03 to 0.3 nmol of fatty acid incorporated min-1 (10(6) cells)-1. Competitive inhibition occurs between fatty acids while glucose, aminoacids and lactate do not compete with palmitate for the entry into the cells. The analysis of unesterified fatty acids from the usual culture medium and from the cells show a gradient of concentration up to 54-fold; moreover experiments performed in minimal medium at 20 degrees C show that fatty acids accumulate up to 28-fold in the cells. Efflux rates can be measured after loading the cells at 20 degrees C; the curves are bimodal and the pseudo first-order rate constants thus determined are in the order of 0.5 min-1, as opposed to 2.5 to 5.0 min-1 for the passive-diffusion component calculated for the influx rates. Studies on the role of serum albumin at constant and at variable fatty acid-albumin molar ratios indicate that the rate of uptake is controlled by the total fatty acid concentration and not solely by the concentration of unbound fatty acids. No labelled fatty acid was found to be bound to the cytoplasmic fraction supposed to contain the fatty acids-binding protein; our results are in favour of the presence of a specific transport system for fatty acids either at the level of subcellular organelles or more likely at the surface of cardiac cells.

Animals↗
PubMed1976

Esterolytic activities of rat intestinal mucosa. 1. Characterization, cellular distribution and subcellular localization of a glycerol-ester hydrolase.

The preferential cellular distribution in the villus tip and the subcellular localization in the endoplasmic reticulum of an intestinal glycerol-ester hydrolase from rat mucosa are described. The enzyme is shown not to be from either pancreatic or bacterial origin; it catalyzes the hydrolysis of short- and medium chain triglycerides and of p-nitrophenylacetate. Contrarily to the specificity found for the pig intestinal lipase (Serrero, Négrel and Ailhaud, 1975), no activity is detectable against acylCoA; a thiolester hydrolase different from the glycerol-ester hydrolase was demonstrated after differential solubilization and chromatographic separation. A high proportion of glycerol-ester hydrolase is present in the intestinal lumen; its possible complementary role in lipid degradation is discussed.

Aging↗
PubMed1976

Esterolytic activities of rat intestinal mucosa. 2. Purification and properties of a glycerol-ester hydrolase.

A glycerol-ester hydrolase from rat intestinal cells has been purified using chromatography on carboxyhexanoyl-Sepharose-glyceryldioctanoate and preparative gel electrophoresis. The enzyme gives a single band by analytical gel electrophoresis; it is a monomer of molecular weight 68000. The optimum pH for its action on glyceryl tributyrate is between 8.0 and 8.5; the activation energy was calculated to be 8.7 kcal x mol-1 (36.4 kJ/mol). Its substrate specificity is mainly directed against esters of glycerol and of primary monoalcohols. Similarly to pancreatic lipase but contrary to liver esterase, it is inhibited by bile salts; relief of this inhibition by colipase is only observed for pancreatic lipase. The possible role of the glycerol-ester hydrolase in the absorption of short and of medium chain triglycerides is discussed.

Animals↗
PubMed1972

Isolation and Characterization of Mutants of Escherichia coli with Cellular Division Selectively Affected by Growth on Fatty Acids.

Isolation and characterization of mutants of Escherichia coli that beta-oxidize fatty acids at normal rates, but which divide very slowly when grown on fatty acids, are described. These mutants grow normally on other carbon sources. By growth on oleate, experiments with radioactive precursors showed that the rates of incorporation into ribonucleic acid, protein, and cell wall were comparable to those observed with the parent, whereas the rate of incorporation into phospholipids was slightly decreased. Under these conditions the rate of incorporation of (32)P-orthophosphate into deoxyribonucleic acid was low. On the other hand, by growth on oleate, neither gross mass increase in the different macromolecules nor loss of viability was observed, whereas in the presence of inducer the derepression of the lac operon enzymes occurred. Therefore, extensive turnover of the macromolecules is involved when these mutants are grown on fatty acids. Studies of the crypticity and of the binding of 1-anilino-8-naphthalene sulfonate show differences in membrane structure between the mutants and the constitutive parent. Properties of these mutants, which are affected in the process of cellular division, are discussed.

Journal Article↗
PubMedDate not supplied

Fatty acids and adipose cell differentiation.

Fatty acids are important metabolic substrates for adipose tissue. In preadipose cells, fatty acids are also potent inducers of various genes encoding proteins directly involved in fatty acid metabolism. On a longer-term basis, fatty acids induce the terminal differentiation of preadipose to adipose cells. Fatty acids act primarily at a transcriptional level. A member of the steroid/thyroid hormone receptor superfamily has been identified by cDNA cloning from a mouse Ob1771 preadipose cell library. This receptor is likely the fatty acid-activated receptor implicated in the transcriptional effects of fatty acids in adipose cells. Thus fatty acids appear to play a new role as signal transducing molecules which are involved in adipose cell differentiation.

Adipocytes↗
PubMedDate not supplied

Effects of high-fat diet, angiotensinogen (agt) gene inactivation, and targeted expression to adipose tissue on lipid metabolism and renal gene expression.

To address the role of angiotensinogen (agt) in lipid metabolism and its potential endocrine effects in vivo, we studied the effects of high-fat diet (HFD) on adult, 28-week-old agt knockout (KO) mice compared to wild type (WT) mice. Recent studies (Massiera et al., 2001) have demonstrated that reexpression of agt in adipose tissue of KO mice normalized adiposity, blood pressure, and kidney abnormalities. We therefore used microarray analysis to investigate changes in gene expression profile in kidneys of KO vs. Tg-KO mice, where agt expression is restricted to adipose tissue. Body weight, adiposity and insulin levels were significantly decreased (p < 0.05) in KO mice on a chow diet (CD) compared to WT mice, while circulating leptin levels were similar. On a high-fat diet, KO mice exhibited significantly lower bodyweight (p < 0.05), adiposity (p < 0.05), leptin, and insulin levels (p < 0.05) compared to WT mice. In agreement with previously reported changes in kidney histology, agt KO mice displayed altered expressions of genes involved in blood pressure regulation and renal function, but these levels were corrected by reexpression of agt in adipose tissue. Collectively, these findings further document important endocrine roles of adipocyte agt, in part via regulation of lipid metabolism and kidney homeostasis.

Adipose Tissue↗