Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1990-1994  (4)
  • Rat insulinoma cell line  (2)
  • Blood pressure  (1)
  • Chemical modification  (1)
  • 1
    ISSN: 1432-0428
    Keywords: 32–33 splet-proinsulin ; Total cholesterol ; high density lipoprotein cholisterol ; plasminogen activator inhibitor ; Blood pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Standard radioimmunoassay for insulin may substantially overestimate levels of insulin because of cross-reaction with other insulin-like molecules. We have measured concentrations of insulin, intact proinsulin and 32–33 split proinsulin using two-site monoclonal antibody based immunoradiometric assays, and of insulin by a standard radioimmunoassay (“immunoreactive insulin”) in 51 Type 2 (noninsulin-dependent) diabetic subjects in the fasting state. The relationships of these concentrations were sought with those of total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol, triglyceride, plasminogen activator inhibitor, blood pressure, and indices of body fat distribution. Significant relationships were apparent between concentrations of “immunoreactive insulin” as measured by standard radioimmunoassay and triglyceride (r s=0.42, p〈0.001), total cholesterol (r s=0.25, p=0.038), high density lipoprotein cholesterol (r s=−0.30, p=0.018) and body mass index (r s=0.30, p=0.017), but only the relationships with triglyceride (r s=0.36, p=0.006) and body mass index (r s=0.26, p=0.034) remained significant when concentrations of immunoradiometrically measured insulin were employed. Concentrations of 32—33 split proinsulin, which comprises the major insulin-like molecule in these subjects, correlated positively with triglyceride (r s=0.33, p=0.009), total cholesterol (r s=0.23, p=0.050), and plasminogen activator inhibitor (r s=0.26, p=0.049), and negatively with high density lipoprotein cholesterol (r s=−0.29, p=0.021). Concentrations of “immunoreactive insulin” and immunoradiometric assay insulin showed significant positive correlaion with both systolic (r s=0.24, p=0.044 and r s=0.29, p=0.020 respectively), and diastolic blood pressure (r s=0.48, p〈0.001 and n=0.42, p=0.001 respectively), while those of intact proinsulin and 32–33 split proinsulin correlated only with diastolic blood pressure (r s=0.33, p=0.009 and r s=0.31, p=0.014 respectively). Using multiple regression analysis, and including age, sex, race and body mass index in the analyses, concentrations of intact proinsulin and 32–33 split proinsulin, but not immunoradiometric assay insulin, were significantly related to diastolic blood pressure. When all three molecules were incorporated into a single model, only 32–33 split proinsulin was related to diastolic blood pressure (F-change=6.91, [5,43 degrees of freedom]; p=0.012). Thus, high concentrations of insulin-like molecules are associated with changes in recognised cardiovascular risk factor in patients with Type 2 (non-insulin-dependent) diabetes mellitus.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    The journal of membrane biology 141 (1994), S. 101-112 
    ISSN: 1432-1424
    Keywords: Rat insulinoma cell line ; CRI-G1 ; Nucleotide regulation ; Calcium-activated nonselective cation channel ; Patch clamp
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The nucleotide regulation of a calcium-activated nonselective cation (Ca-NS+) channel has been investigated in the rat insulinoma cell line CRI-G1. The activity of the channel is reduced by both AMP and ADP (1–100 μm) in a concentration-dependent manner, with AMP being more potent than ADP. At lower concentrations (0.1–5 μm), both ADP and AMP activate the channel in some patches. Examination of the nucleotide specificity of channel inhibition indicates a high selectivity for AMP over the other nucleotides tested with a rank order of potency of AMP 〉 UMP 〉 CMP ≥GMP. Cyclic nucleotides also modulate channel activity in a complex, concentration-dependent way. Cyclic AMP exhibits a dual effect, predominantly increasing channel activity at low concentrations (0.1–10 μm) and reducing it at higher concentrations (100 μm and 1 mm). Specificity studies indicate that the cyclic nucleotide site mediating inhibition of channel activity exhibits a strong preference for cyclic AMP over cyclic GMP, with cyclic UMP being almost equipotent with cyclic AMP. Cyclic IMP and cyclic CMP are not active at this site. The cyclic nucleotide site mediating activation of the channel shows much less nucleotide specificity than the inhibitory site, with cyclic AMP, cyclic GMP and cyclic IMP being almost equally active.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-1424
    Keywords: KATP channels ; Chemical modification ; Sulfhydryl group ; Basic amino acids ; Pancreatic β-cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: 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.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-1424
    Keywords: Calcium-activated nonselective channel ; Rat insulinoma cell line ; CRI-G1 ; Pyridine nucleotides β-NAD+-NS+ channel ; Nucleotide regulation ; AMP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The activity of a calcium-activated nonselective (Ca-NS+) channel in a rat insulinoma cell line (CRI-G1) is inhibited by pyridine nucleotides in excised patches. The effects of all four pyridine nucleotides tested, β-NAD+, β-NADH, β-NADP+ and β-NADPH were very similar when tested at 0.1 mm, and at 1 mm the phosphorylated forms, β-NADP+ and β-NADPH, appeared to be slightly more potent than β-NAD+ and β-NADH. All the pyridine nucleotides tested reduced both the open state probability of the channel and the number of functional channels observed in a single patch. The application of β-NAD+, but not of the other nucleotides tested, to the cytoplasmic surface of isolated inside-out patches from CRI-G1 cells opened a novel nonselective cation channel (the β-NAD+-NS+ channel). The activity of this new channel is calcium sensitive and may also be inhibited by AMP.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...