Membrane vesicles from brown adipose tissue: A tool for the study of amino acid transport. The case of L-alanine

1992 ◽  
Vol 12 (2) ◽  
pp. 115-122
Author(s):  
A. Rodríguez-Martín ◽  
N. Bel ◽  
X. Remesar
Keyword(s):  
Adipose Tissue ◽  
Amino Acid ◽  
Brown Adipose Tissue ◽  
Density Gradient ◽  
Gradient Method ◽  
Amino Acid Transport ◽  
Membrane Vesicles ◽  
Acid Transport ◽  
Brown Adipose

A density gradient method is used to isolate membrane vesicles from brown adipose tissue. These respond to changes in osmolarity and show the classical overshoot pattern when L-alanine uptake is assayed. Transport is shown to be effected by two components: a linear (Kd=0.498 min−1) and Na+-dependent saturable component (Km=2.3 mM) and a Vmax=19.9 pmol/μg protein·min). This pattern is similar to that shown by cells isolated from brown adipose tissue.

scholarly journals Correlation of Plasma Amino Acid and Anthropometric Profiles with Brown Adipose Tissue Density in Humans

2021 ◽  
Vol 10 (11) ◽  
pp. 2339
Author(s):  
Miyuki Kuroiwa ◽  
Sayuri Hamaoka-Fuse ◽  
Masahiro Sugimoto ◽  
Yuko Kurosawa ◽  
Yasuko Aita ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Amino Acid ◽  
Brown Adipose Tissue ◽  
Near Infrared ◽  
Winter Season ◽  
Plasma Amino Acid ◽  
Anthropometric Parameters ◽  
Tissue Density ◽  
Brown Adipose ◽  
Branched Chain

This study examined the relationship between plasma amino acid (AA) concentrations, including branched-chain AAs, and brown adipose tissue density (BAT-d). One hundred and seventy-three subjects (69 men, 104 women) aged 22–68 years were recruited during the winter season. AAs were comprehensively quantified using liquid chromatography-time-of-flight-mass spectrometry. The total hemoglobin concentration in the supraclavicular region ([total-Hb]sup), an indicator of BAT-d, was assessed using near-infrared time-resolved spectroscopy. Anthropometric parameters, including age, percentage of body fat, and visceral fat, were evaluated. Factors associated with higher (≥74 µM) or lower (<74 µM) [total-Hb]sup were investigated by multiple logistic regression models that included AA concentrations alone (model 1) or AA concentrations and anthropometric parameters (model 2) as independent variables. When adjusted for the false discovery rate, [total-Hb]sup was positively correlated with glycine and asparagine levels in men and with the serine level in both men and women and was negatively correlated with the branched-chain AA concentration in men. Models 1 and 2 correlated with higher or lower BAT-d for men (r = 0.73, p = 0.015) and women (r = 0.58, p = 0.079) and for men (r = 0.82, p = 0.0070) and women (r = 0.70, p = 0.020), respectively. A combination of anthropometric parameters and plasma AA concentrations could be a reliable biomarker for higher and lower BAT-d.

scholarly journals Regulation of Na+ transport in brown adipose tissue

1986 ◽  
Vol 235 (2) ◽  
pp. 545-552 ◽  
Author(s):  
K F LaNoue ◽  
C Koch ◽  
D Strzelecka ◽  
T P Kobylski
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Membrane Vesicle ◽  
Membrane Vesicles ◽  
Fat Cell ◽  
Isolated Cells ◽  
Intact Cells ◽  
Dependent Atpase ◽  
Brown Adipose ◽  
Active Transport System

In order to test the hypothesis that Na+, K+-ATPase (Na+,K+-dependent ATPase) is involved in the noradrenaline-mediated stimulation of respiration in brown adipose tissue, the effects of noradrenaline on Na+,K+-ATPase in isolated brown-fat-cell membrane vesicles, and on 22Na+ and K+ (86Rb+) fluxes across the membranes of intact isolated cells, were measured. The ouabain-sensitive fraction of the K+-dependent ATPase activity in the isolated membrane-vesicle preparation was small and was not affected by the presence of noradrenaline in the incubation media. The uptake of 86Rb+ into intact hormone-sensitive cells was inhibited by 80% by ouabain, but it was insensitive to the presence of noradrenaline. 22Na+ uptake and efflux measured in the intact cells were 8 times more rapid than the 86Rb+ fluxes and were unaffected by ouabain. This indicated the presence of a separate, more active, transport system for Na+ than the Na+,K+-ATPase. This is likely to be a Na+/Na+ exchange activity under normal aerobic conditions. However, under anaerobic conditions, or conditions simulating anaerobiosis (2 mM-NaCN), the unidirectional uptake of Na+ increased dramatically, while efflux was unaltered.

scholarly journals A role for aminopeptidase N in Na+-dependent amino acid transport in bovine renal brush-border membranes

1993 ◽  
Vol 290 (1) ◽  
pp. 59-65 ◽  
Author(s):  
S Plakidou-Dymock ◽  
M J Tanner ◽  
J D McGivan
Keyword(s):  
Amino Acid ◽  
Brush Border ◽  
Amino Acid Transport ◽  
Membrane Vesicles ◽  
Aminopeptidase N ◽  
Aminopeptidase Activity ◽  
Acid Transport ◽  
Transport Activity ◽  
Renal Brush Border Membrane ◽  
Renal Brush Border

A monoclonal antibody FD19 which removes reconstitutable Na(+)-dependent amino acid transport activity from solubilized bovine renal brush-border membrane vesicles was found to react specifically with the enzyme aminopeptidase N. Cleavage of aminopeptidase N from the membranes with papain inhibited Na(+)-dependent amino acid transport activity without affecting that of alpha-methyl D-glucoside. Removal of aminopeptidase substantially increased the Km values for the Na(+)-dependent transport of alanine, glutamine, leucine and phenylalanine without affecting the Vmax. Both Na(+)-dependent amino acid transport and aminopeptidase activity in intact vesicles were competitively inhibited by amino acids with very similar specificity. These results suggest that the amino acid-binding sites of aminopeptidase N and the transporter interact in some way to increase the Km of the transport process for its substrates. However, independent direct inactivation of the transport system by papain cannot be ruled out.

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