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  • Digitale Medien  (3)
  • 1990-1994  (3)
  • hypertriglyceridaemia  (2)
  • Chemical modification  (1)
  • 1
    ISSN: 1432-1424
    Schlagwort(e): KATP channels ; Chemical modification ; Sulfhydryl group ; Basic amino acids ; Pancreatic β-cells
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The effects of several group-specific chemical reagents were examined upon the activity of the ATP-sensitive potassium (KATP) channel in the CRI-G1 insulin-secreting cell line. Agents which interact with the sulfhydryl moiety (including 1 mM N-ethylmaleimide (NEM), 1 mM 5,5′-dithio-bis-(2-nitrobenzoic acid) (DNTB) and 1 mm o-iodobenzoate) produced an irreversible inhibition of KATP channel activity when applied to the intracellular surface of excised inside-out patches. This inhibition was substantially reduced when attempts were made to eliminate Mg2+ from the intracellular compartment. ATP 50 μm and 100 μm tolbutamide were each shown to protect against the effects of these reagents. The membrane impermeable DNTB was significantly less effective when applied to the external surface of outside-out patches. Agents which interact with peptide terminal amine groups and ɛ amino groups of lysine [1 mm methyl acetimidate and 1 mm trinitrobenzene sulfonic acid (TNBS)] and also the guanido group of arginine (1 mm methyl glyoxal) produced a Mg2+-dependent irreversible inhibition of KATP channel activity which could be prevented by ATP but not tolbutamide. The irreversible activation of the KATP channel produced by the proteolytic enzyme trypsin was prevented only when methyl glyoxal and methyl acetimidate were used in combination to inhibit channel activity. Radioligand binding studies showed that the binding of 3H glibenclamide was unaffected by any of the above agents with the exception of TNBS which completely inhibited binding with a EC50 of 307 ±6 μm. These results provide evidence for the presence of essential sulfhydryl (possibly cysteine), and basic amino acid (possibly lysine and arginine) residues associated with the normal functioning of the KATP channel. Furthermore, we believe that the sulfhydryl group in question is situated at the internal surface of the membrane, possibly near to the channel pore.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1432-0428
    Schlagwort(e): Non-insulin-dependent diabetes mellitus ; impaired glucose tolerance ; hypertriglyceridaemia ; hyperinsulinaemia ; non-esterified fatty acid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Although plasma insulin and triglyceride concentrations are positively correlated in many studies, the relationships between insulin resistance, insulin secretion and hypertriglyceridaemia remain unclear. To study these associations, subjects between the ages of 40 and 64 were randomly selected from a general practice register and invited to attend for a standard oral glucose tolerance test for measurement of insulin, triglyceride and non-esterified fatty acid concentrations. The study comprised 1122 subjects who were not previously known to have diabetes and who completed the test. Using the World Health Organisation criteria, 51 subjects were classified to have non-insulin-dependent diabetes mellitus, 188 had impaired glucose tolerance and 883 subjects had normal glucose tolerance. Triglyceride concentrations in subjects with glucose intolerance were elevated compared to those in control subjects, even after adjustment for age, obesity and gender (p〈0.001 for subjects with diabetes and p〈0.01 for those with impaired glucose tolerance compared to normal subjects). In separate multiple regression analyses for males and females, the most important determinants of the plasma triglyceride concentration were the area under the non-esterified fatty acid suppression curve (p〈0.001 in both genders) and the waist-hip ratio (p〈0.001 for men and 〈0.01 for women). The fasting insulin concentration was independently associated with triglyceride concentration in women only (p〈0.01). The most important determinant of the area under the non-esterified fatty acid suppression curve in men was the 30-min insulin increment, a measure of insulin secretion, (p〈0.001) whereas for women age (p〈0.001) and the body mass index (p〈0.01) were the most important.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1432-0428
    Schlagwort(e): Key words Non-insulin-dependent diabetes mellitus ; impaired glucose tolerance ; hypertriglyceridaemia ; hyperinsulinaemia ; non-esterified fatty acid.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Although plasma insulin and triglyceride concentrations are positively correlated in many studies, the relationships between insulin resistance, insulin secretion and hypertriglyceridaemia remain unclear. To study these associations, subjects between the ages of 40 and 64 were randomly selected from a general practice register and invited to attend for a standard oral glucose tolerance test for measurement of insulin, triglyceride and non-esterified fatty acid concentrations. The study comprised 1122 subjects who were not previously known to have diabetes and who completed the test. Using the World Health Organisation criteria, 51 subjects were classified to have non-insulin-dependent diabetes mellitus, 188 had impaired glucose tolerance and 883 subjects had normal glucose tolerance. Triglyceride concentrations in subjects with glucose intolerance were elevated compared to those in control subjects, even after adjustment for age, obesity and gender (p 〈 0.001 for subjects with diabetes and p 〈 0.01 for those with impaired glucose tolerance compared to normal subjects). In separate multiple regression analyses for males and females, the most important determinants of the plasma triglyceride concentration were the area under the non-esterified fatty acid suppression curve (p 〈 0.001 in both genders) and the waist-hip ratio (p 〈 0.001 for men and 〈 0.01 for women). The fasting insulin concentration was independently associated with triglyceride concentration in women only (p 〈 0.01). The most important determinant of the area under the non-esterified fatty acid suppression curve in men was the 30-min insulin increment, a measure of insulin secretion, (p 〈 0.001) whereas for women age (p 〈 0.001) and the body mass index (p 〈 0.01) were the most important. [Diabetologia (1994) 37: 889–896]
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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