Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Postabsorptive plasma amino acid and insulin concentrations were determined in subjects with hyperplastic obesity and in nonobese controls before and after a 6-wk period of physical training. After the training period the plasma concentrations of insulin and leucine decreased and the concentration of alanine increased in the obese subjects. No changes were noticed in the controls. The obese subjects had elevated plasma levels of valine, isoleucine, leucine, tyrosine, and phenylalanine before as well as after physical training. The concentrations of these amino acids were correlated to the plasma insulin level and to lean body mass before but only to lean body mass after physical training. It is suggested that the lean body mass, whick is higher in hyperplastic obesity, contributes to the elevated concentrations of amino acids, and it is unlikely that the insulin decreases in the obese subjects after physical training is mediated through an effect of amino acids on insulin secretion.
 ...
PMID:Effects of physical training and lean body mass of plasma amino acids in man. 68 Dec 2

Rates of absorption of leucine, glycylleucine, and glucose, and rates of hydrolysis of maltose were determined in the jejunum of a group of obese persons before and at intervals (between 2 and 20 montsh) after jejunoileal bypass for the treatment of obesity. The leucine absorption rate was significantly reduced after the bypass, but the absorption rates of glycylleucine and glucose as well as the hydrolysis rate of maltose were unchanged. Light microscopic investigation of the jejunal mucosa, obtained by a peroral biopsy technique before and at 7 months after by bypass operation, did not reveal any change in the histological appearance of this tissue. The plasma aminograms of all 7 patients were compared before and at intervals after the bypass operation; all exhibited a constant pattern of change that was characterized by significant decreases in the concentrations of serine and glycine and by significant decreases in the concentrations of valine, isoleucine, leucine, tyrosine, and phenylalanine. This pattern of change, which is characteristic of protein depletion, persisted during the entire period of observation. Two of these 7 patients developed laboratory evidence of hepatic dysfunction. It is concluded that (1) protein depletion is common to all patients with jejunoileal bypass with or without hepatic dysfunction; and (2) protein depletion results in a sustained reduction in free amino acid absorption in the jejunum.
 ...
PMID:Absorptive and digestive function of the jejunum after jejunoileal bypass for treatment of human obesity. 96 65

The effects of cafeteria diet-induced obesity upon in vitro uptake of L-Alanine, Glycine, L-Lysine, L-Glutamine, L-Glutamic acid, L-Phenylalanine and L-Leucine by isolated rat erythrocytes have been studied. The total Phe and Leu uptakes followed Michaelis-Menten kinetics. The Glu uptake was fitted to diffusion kinetics. The uptakes of Ala, Gly, Lys and Gln were best explained by a two-component transport: one saturable and one diffusion. Obesity increased the Km value for Ala, Gln and Leu, and the Vmax value for Ala, but decreased the Vmax for Lys. Kinetic parameters of Phe uptake were unaffected by obesity. In addition, the pseudo-first order rate constant (Vmax/Km) for Ala, Gly, Gln, Lys and Leu uptake decreased as a result of cafeteria diet-induced obesity. The Kd value for Ala, Gly, Gln and Glu decreased and that of Lys increased as result of obesity. These adaptations could, at least in part, explain alterations in amino acid distribution between blood cells and plasma related to overfeeding or obesity.
 ...
PMID:Effect of diet-induced obesity on kinetic parameters of amino acid uptake by rat erythrocytes. 148 91

Defects in insulin-receptor function have been associated with insulin-resistant states such as obesity and non-insulin-dependent diabetes mellitus (NIDDM). Several types of mutations in the insulin-receptor gene have been identified in patients with genetic syndromes of extreme insulin resistance. In some patients, insulin resistance results from a decrease in the number of insulin receptors on the cell surface. In one patient with leprechaunism (leprechaun/Minn-1), there is greater than 90% decrease in the levels of insulin-receptor mRNA. This patient is a compound heterozygote for two mutations in the insulin-receptor gene, both of which act in a cis-dominant fashion to decrease levels of mRNA transcribed from that allele. In one allele, there is a nonsense mutation at codon 897. All 22 exons of the other allele have a normal sequence, so that the mutation in this allele appears to map outside the coding sequence of the gene. Impaired insertion in the plasma membrane also causes insulin resistance. In two sisters (patients A-5 and A-8) with type A extreme insulin resistance, there is an 80-90% decrease in the number of insulin receptors expressed on the surface of their cells. Both sisters, whose parents are first cousins, are homozygous for a point mutation in which valine is substituted for phenylalanine at position 382 in the alpha-subunit of the insulin receptor. This mutation retards the posttranslational processing of the receptor and impairs the transport of receptors to the cell surface. Another patient with leprechaunism (leprechaun/Ark-1) is a compound heterozygote with two different mutant alleles of the insulin-receptor gene. In the allele derived from the father, there is a nonsense mutation at codon 672 that truncates the insulin receptor by deleting the COOH-terminal of the alpha-subunit and the entire beta-subunit. This truncated receptor, lacking a transmembrane domain, appears not to be expressed at the plasma membrane. In leprechaun/Ark-1, there is a missense mutation in the allele of the insulin-receptor gene derived from the mother. This point mutation results in substitution of glutamic acid for lysine at position 460 in the COOH-terminal half of the alpha-subunit. This mutation increases receptor affinity and impairs the ability of acid pH to dissociate insulin from the receptor within the endosome. There is a defect in recycling the receptor back to the plasma membrane associated with this defect. This results in an accelerated rate of receptor degradation and a consequent decrease in the number of receptors on the cell surface in vivo.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Mutations in insulin-receptor gene in insulin-resistant patients. 196 73

Twenty obese and 20 lean LA/N-cp male rats and 20 male Sprague-Dawley rats were fed a diet containing either 54 percent sucrose or starch for six weeks. After a 14-16 hour fast, rats were killed. Liver and kidney enzyme activities were determined in the LA/N-cp rats while plasma urea and selected amino acids were determined in all rats. Liver glucose-6-phosphatase (G6PASE), fructose-1,6-bisphosphatase (FBPASE), phosphoenolpyruvate carboxykinase (PEPCK), glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate dehydrogenase (6PGDH), malic enzyme (ME), glucokinase (GK), pyruvate kinase (PK), phosphofructokinase (PFK), glutamic-oxaloacetic-transaminase (GOT), glutamic-pyruvic transaminase (GPT), arginase (ARGASE), arginine-synthase (ARG-SYN) and ornithine transcarbamylase (OTC) levels were significantly affected by phenotype (obese greater than lean). All the above changes in enzyme levels were exaggerated by sucrose-feeding with the exception of PK, PFK, GOT, GPT, ARGASE and ARG-SYN. Kidney cortex G6PASE, PEPCK and ARGASE activities were higher in the obese rats as compared to the lean littermates. Sucrose feeding resulted in higher cortex G6PASE, FBPASE and PEPCK as compared to starch-fed rats. A phenotype effect was noted with plasma glutamate, urea, leucine, isoleucine and valine (obese greater than lean) and a diet effect was seen with aspartate, phenylalanine, leucine and valine (sucrose greater than starch) concentration. Sprague-Dawley rats had higher plasma urea and lower alanine than lean LA/N-cp males. Metabolic obesity in the LA/N-cp rat appears to involve an elevated capacity for pathways of glycolysis, gluconeogensis, lipogenesis and amino acid catabolism in the liver.
 ...
PMID:Effect of dietary carbohydrate on liver and kidney enzyme activities and plasma amino acids in the LA/N-cp rat. 204 12

In order to test the hypothesis that serotonergic activity is abnormal in the brains of genetically obese Zucker rats, levels of serotonin (5-HT); its amino acid precursor, tryptophan (Trp), and its major metabolite, 5-hydroxyindoleacetic acid (5-HIAA) were measured in eight brain regions in groups of obese and non-obese male rats. Plasma albumin levels as well as levels of amino acids and related compounds in plasma and in a cortical sample were also determined in the same animals. While Trp was lower in several brain regions of the obese animals, the only region showing a depressed level of 5-HT in the obese group was the mesencephalon. Obese animals also had a lower amount of 5-HIAA in the diencephalon, but no other differences were significant. Both elevations and depressions were observed in cortical amino acid levels in obese animals. The level of plasma albumin was increased in the obese group. Free Trp was decreased in the plasma of obese rats while levels of other amino acids (methionine, leucine, isoleucine, valine and phenylalanine) which compete with Trp for transport across the blood-brain barrier were elevated. Thus the combination of lower plasma free Trp and increased levels of competitive amino acids appears to contribute to decreased levels of Trp in the brain of genetically obese rats.
 ...
PMID:Brain serotonergic activity and plasma amino acid levels in genetically obese Zucker rats. 618 36

The ratio of plasma concentrations of tryptophan to the sum of neutral amino acids (valine, isoleucine, leucine, phenylalanine and tyrosine) was found to be significantly lower in formula-fed infants as compared to breast-fed infants and to newborns at birth. This tryptophan to neutral amino acids ratio in the blood is thought to control the synthesis of serotonin in the brain. Serotonin deficiency in the developing brain based on a decreased plasma tryptophan to neutral amino acids ratio may contribute to developmental obesity and/or permanent changes of mental capacity and social adaptability as observed in human subjects who had been formula-fed as compared to those who had been breast-fed in neonatal life.
 ...
PMID:Changes of the plasma tryptophan to neutral amino acids ratio in formula-fed infants: possible effects on brain development. 668 52

Young female obese (ob/ob) and lean mice were allowed to self-select from two diets varying in protein and carbohydrate, protein and fat or carbohydrate and fat for 36 days. Obese and lean mice offered a choice between two diets varying in protein and carbohydrate consumed 35 and 30%, respectively, of energy from protein. When two diets varying in protein and fat were fed, both obese and lean mice initially self-selected a higher percentage of energy from protein than when diets varying in protein and carbohydrate were fed. This pattern was rapidly reversed in lean mice and more gradually reversed in obese mice. By the end of this feeding trial, obese and lean mice were self-selecting 26 and 16%, respectively, of energy from protein. When two diets varying in carbohydrate and fat were fed, young obese mice self-selected only 44 +/- 6% of energy from the high fat diet whereas lean mice self-selected 65 +/- 4% of energy from the high fat diet. The ratio of plasma tryptophan to large neutral amino acids (valine, leucine, isoleucine, phenylalanine and tyrosine) showed a strong inverse relationship to protein intake. In summary, replacement of dietary carbohydrate with fat lowered the percentage of energy self-selected as protein. Obese mice, however, continued to consume more energy and more protein than lean mice.
 ...
PMID:Effect of dietary fat on protein intake regulation in young obese and lean mice. 721 39

To investigate the tissue growth and the protein synthesis in vivo in nutritional obesity we used lipid-rich multichoice diet feeding. Young male rats of the Wistar strain were divided in two groups: control and obese. Control rats were fed pelleted nonpurified diet. Obese rats were fed a multichoice diet based on a variety of highly palatable energy-rich human foods for 30 d. Protein intake was kept equal in the groups to avoid its influence on protein turnover. The tissue growth pattern was evaluated by protein, DNA and RNA contents of liver, kidney, heart, skeletal muscles and small intestine. Protein synthesis in vivo was measured in these tissues by the phenylalanine flooding-dose technique. Rats fed the multichoice diet showed significantly greater body growth when compared with rats fed the nonpurified diet. Adipose and other tissue weights were significantly greater in the obese rats. The tissue growth pattern was characterized mainly by hyperplasia. In most tissues the net protein accretion found in obese rats resulted from an enhancement in the fractional rate of protein synthesis. The greater protein synthesis was due to an increase in the efficiency of ribosomes in kidney, heart and skeletal muscle and to an increase in the synthetic capacity in liver and small intestine. These data suggest that excess energy intake when protein intake is adequate stimulates tissue growth and protein synthesis in rats.
 ...
PMID:Protein synthesis is stimulated in nutritionally obese rats. 753 6

Growth hormone (GH) secretion is regulated by a complex system of central and peripheral signals. Recently, a new GH-releasing hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) called GHRP-6 which specifically releases GH has been studied. In the present work the mechanism of action of GHRP-6 has been addressed in experimental animal models as well as in obese subjects. GHRP-6 releases GH independently of the hypothalamic factors GHRH and somatostatin and is a powerful GH releaser in obesity.
 ...
PMID:Regulation of growth hormone secretion by the growth hormone releasing hexapeptide (GHRP-6). 792 Sep 95


1 2 3 4 5 6 7 8 9 10 Next >>