Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have purified a protein which has somatomedin-like properties from the serum of Wistar-Furth rats bearing a growth hormone producing pituitary tumor (MStT/W15). Activity was measured by a placental insulin and/or somatomedin C radioreceptor assay (SmC-RRA). The serum was initially filtered through Sephadex G-150 equilibrated with 0.1 M NH4HCO3 and 0.02% NaN3. On the G-150 column, radioreceptor insulin (RRI) and radioreceptor somatomedin C (RRSm-C) activities coincided and appeared predominantly in the 160,000 mol wt range with a minor proportion in the 50,000 mol wt range. The pooled active fractions were boiled for 30 min at pH 5.5. After removing denatured protein by centrifugation, the extract was passed through G-50 Sephadex equilibrated with 1% formic acid and 0.15 M NaCl. Sixty to 90% of the SmC-RRA activity in the effluent appeared in the 9000 mol wt range. This material has an isoelectric focusing range of 8.4--9.6, similar to that described for human somatomedin C. On SDS-urea polyacrylamide gel electrophoresis only one protein band was seen. The isolated peptide (rSm) stimulated sulfate uptake in hypophysectomized rat cartilage. The potency of two preparations was variously assayed from 14.0 to 54.7 units/mg. Rat somatomedin was iodinated and purified by absorption on and elution from placental membranes. Eight to 12% of rat [125I]Sm was specifically bound by human placental membranes. Rat [125I]Sm was displaced by hSmC and rSm and human NSILA-S, partially displaced by procine proinsulin and poorly displaced by rat insulin. In preliminary studies, rat [125I]Sm was displaced from receptors on human placental membranes by sera from pituitary tumor bearing rats greater than normal rat sera greater than hypophysectomized rat sera.
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PMID:Isolation of a somatomedin from plasma of rats bearing growth hormone secreting tumors. 18 31

We have studied the relationship between abnormalities of the growth hormone-somatomedin axis and growth in 26 children previously treated for acute lymphatic leukemia. Each child had previously received cranial irradiation, was in complete clinical and hematologic remission, and off all drugs. The mean standing height SDS of the 26 children was significantly less than normal. There was no significant difference between the mean standing height SDS, height velocity SDS, somatomedin activities, and degree of bone age retardation between the 17 children who received the higher dose of cranial irradiation (Group 1) and the nine who had the lower dose of cranial irradiation (Group II). Furthermore, there was no significant reduction in mean height velocity SDS, somatomedin activity, or bone age in either group when compared to normal age-matched controls. The peak GH responses to both insulin hypoglycemia and an arginine test were significantly lowered in Groups I and II when compared to a control group of children. We conclude that only a minority of children, who previously received cranial irradiation for ALL were clinically GH deficient and, therefore, likely to benefit from GH therapy despite the finding that the majority of these children had reduced GH responses to pharmacologic stimuli.
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PMID:Normal growth despite abnormalities of growth hormone secretion in children treated for acute leukemia. 22 28

We have developed a new technique to solubilize apolipoprotein B (ApoB) in aqueous solutions. The procedure involves stirring ApoB in 6 M guanidine/20 mM NH4Cl/NH4OH in the presence of cupric ammonia complexes at pH 9.7 for 20 h in N2, and then removing these reagents by a series of dialysis in N2. The resulting Cu(NH3)4(2)+-treated (Cu2+-treated) ApoB is soluble in aqueous buffers of pH above 8.3 or below 3. Parallel experiments carried out on control proteins, human albumin, alpha-lactalbumin, and insulin, indicated no change in molecular weight and no creation of a new NH2-terminal amino acid after Cu2+-treatment. By Edman degradation, the Cu2+-treated ApoB showed no detectable NH2-terminal amino acid. These results showed that the mechanism of Cu2+-solubilization of ApoB was not due to the cleavage of peptide bonds. Electrophoresis on urea-polyacrylamide gel, Cu2+-treated ApoB showed the same number of bands as the non-treated ApoB in the separating gels (7%) near the cathode, suggesting the heterogeneity of ApoB. In SDS-polyacrylamide gel (10%), the reduced and Cu2+-treated ApoB migrated with the similar mobilities to the monomer or dimer of human albumin. Antibodies raised against Cu2+-treated ApoB gave at least two immunoprecipitin lines against the Cu2+-treated ApoB as well as the non-treated guanidine-HCl-soluble ApoB, suggesting the presence of non-identical subunits.
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PMID:A novel method for converting apolipoprotein B, the major protein moiety of human plasma low density lipoproteins, into a water-soluble protein. 22 36

The secretory pattern of insulin and the rate of conversion of proinsulin to insulin were studied in isolated pancreatic islets from normoglycemic (buffer-infused for 24 hours) and hyperglycemic (glucose-infused for 24 hours) rats. The profiles of insulin secretion obtained during one hour of perifusion were markedly different in the two groups. The rate of insulin secretion by islets from the hyperglycemic rats was initially very high but progressively declined during the late period of the perifusion. The reverse pattern was found with the islets from buffer-infused rats. For the estimation of the rate of proinsulin conversion, islets were pulse-labeled with L-[4,5-3H]-leucine for 15 minutes and "chase"-incubated for 30 and 60 minutes. Labeled rat proinsulin and rat insulins in the medium and in the islet extracts were separated by a validated SDS-urea electrophoretic acrylamide procedure following immunoprecipitation. The conversion rate was estimated from the radioactivity in the insulin band, expressed as a per cent of the radioactivity in the proinsulin + insulin bands. Islets from hyperglycemic rats converted newly synthesized proinsulin to insulin at significantly higher rates than did control islets.
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PMID:Secretion of insulin in a perifusion system and conversion of proinsulin to insulin by pancreatic islets from hyperglycemic rats. 32 5

The separation of polypeptides treated with SDS was studied using G3000SW packing prepared from silica for high-speed gel filtration. The peaks of ovalbumin, chymotrypsinogen A, cytochrome c, aprotinin, and insulin B chain were completely separated in the presence of 0.1% SDS and 0.05 M sodium phosphate buffer (pH 7.0). A plot of the logarithm of molecular weight of polypeptides versus Kd was linear over a molecular weight range of 3,000 to 50,000 at the above concentrations of SDS and sodium phosphate. The slopes of the plots of log molecular weight versus Kd depend to a significant extent on the concentration of the sodium phosphate buffer (pH 7.0).
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PMID:High-speed gel filtration of polypeptides in sodium dodecyl sulfate. 51 43

Insulin receptor characteristics were examined in purified brush border membrane from the syncytiotrophoblast of the normal human placenta and quantified during membrane preparation. Insulin receptor concentration was enriched 10- to 15-fold in this preparation, and insulin receptor specific activity followed closely the enrichment values for microvillus plasma membrane markers, alkaline phosphatase, Ca2+- and Mg2+-ATPase, and 5'-nucleotidase during cell fractionation. Insulin receptor concentrations and marker enzyme analyses were compared in whole homogenate, mitochondrial, microsomal, and microvillus fractions, and these fractions were characterized by SDS-gel electrophoresis. Microvillus insulin receptor interactions were dependent on time, [125I]iodoinsulin concentration, protein, and unlabeled hormone concentrations. Competition studies with porcine insulin and [125I]iodoinsulin for this receptor revealed a curvilinear Scatchard plot. Insulinase was demonstrated at 37 C but was minimal at 24 C in the microvillus fraction. Electron microscopy of the microvillus membrane preparation revealed its composition to be mainly spherical closed membrane vesicles and brush border fragments. Sodium dodecyl sulfate polyacrylamide and isoelectric focusing gels of membrane fractions were compared. Actin was tentatively identified as a major microvillus membrane protein and was further fractionated: beta-Actin and gamma-actin were present in approximately equal concentrations. The localization of the insulin receptor in the microvillus brush border of the human placenta suggests that this receptor interacts with maternal, rather than fetal insulin.
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PMID:Characteristics of the microvillus brush border of human placenta: insulin receptor localization in brush border membranes. 75 22

SDS-urea polyacrylamide gel electrophoresis of mouse milk proteins revealed the presence of three major phosphoproteins (caseins) of m.w. 44,000, 26,000 and 22,000 daltons. By using an antiserum against crude casein fraction, an immunoprecipitation method was developed for the quantitative measurement of the rate of milk protein synthesis in the mouse mammary tissue. Cultivation of mammary explants with insulin, cortisol and prolactin resulted in the induction of milk protein synthesis as evidenced by the incorporation of [3H]amino acid and [32P]orthophosphate into immune precipitable materials. The present immunoprecipitation method coupled with a simplified explant culture technique provides a suitable procedure for the study of mouse mammary gland differentiation.
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PMID:Hormonal control of milk protein synthesis in cultured mouse mammary explants. 91 58

The diagnosis of insufficiency of exocrine pancreatic secretion was made in two infants after demonstration of a marked decrease in the flow rate of enzyme secretions during the duodenal infusion of milk and after the IV injection of C.C.K.-P.Z. The two infants had a normal sweat test. One had pancreatic lipomatosis with neuropaenia, whilst the other had pancreatic deficiency which did not fall into the context of Shwachman's syndrome. This study suggests that the absence of exocrine pancreatic secretion is accompanied by multiple abnormalitites : decreased absorption of fats and vitamin B12 and, it would appear, variations in certain activities of the jejunal mucosa and decreased insulin stimulation from the intestine. Such a situation reflects the complexity of the relations established between the organs participating in the processes of absorption and digestion.
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PMID:[Insufficiency of secretion from the exocrine pancreas in infants (excluding mucoviscidosis) Diagnosis and consequences]. 101 26

A mouse monoclonal antibody (CT-1) was prepared against the C-terminal peptide sequence of the human insulin receptor beta-subunit (KKNGRILTLPRSNPS). The antibody reacted with native human and rat insulin receptors in solution, whether or not insulin was bound and whether or not the receptor had undergone prior tyrosine autophosphorylation. The antibody also reacted specifically with the receptor beta-subunit on blots of SDS/polyacrylamide gels. Preincubation of soluble receptors with antibody increased the binding of 125I-insulin approx. 2-fold. The antibody did not affect insulin-stimulated autophosphorylation, but increased the basal autophosphorylation rate approx. 2-fold. The amino acid residues contributing to the epitope for CT-1 were defined by construction and screening of an epitope library. Oligonucleotides containing 23 random bases were synthesized and ligated into the vector pCL627, and the corresponding peptide sequences expressed as fusion proteins in Escherichia coli were screened by colony blotting. Reactive peptides were identified by sequencing the oligonucleotide inserts in plasmids purified from positive colonies. Six different positive sequences were found after 900,000 colonies had been screened, and the consensus epitope was identified as GRVLTLPRS. Phosphorylation of the threonine residue within this sequence (corresponding to the known phosphorylation site Thr-1348 in the insulin receptor) decreased the affinity of antibody binding approx. 100-fold, as measured by competition in an e.l.i.s.a. Antibody CT-1 was used for immunoaffinity isolation of insulin receptor from detergent-solubilized human placental or rat liver microsomal membranes. Highly purified receptor was obtained in 60% yield by binding to CT-1-Sepharose immunoadsorbent and specific elution with a solution of peptide corresponding to the known epitope. This approach to purification under very mild conditions may in principle be used with any protein for which an antibody is available and for which a peptide epitope or 'mimotope' can be identified.
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PMID:A monoclonal anti-peptide antibody reacting with the insulin receptor beta-subunit. Characterization of the antibody and its epitope and use in immunoaffinity purification of intact receptors. 128 Jan 10

Cultured cardiac myocytes from adult Sprague-Dawley rats express both insulin-like growth factor-I (IGF-I) receptors and insulin-like growth factor-II/mannose 6-phosphate (IGF-II/Man6P) receptors and respond to IGF-I with a dose-dependent accumulation of inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] and inositol 1,4-bisphosphate [Ins(1,4)P2]. Specific binding of [125I]IGF-I to isolated membranes from cultured cardiac myocytes amounted to 1-1.2%. Binding of [125I]IGF-I was inhibited by unlabeled IGF-I at nanomolar concentrations and insulin at much higher concentrations. These data suggest that IGF-I binds to its own receptor on rat cardiac myocytes. Competitive binding studies using isolated membranes from cardiac myocytes and [125I]IGF-II showed 2-4% specific binding. Binding of [125I]IGF-II was inhibited by IGF-II and much less potently by IGF-I and insulin. Immunoglobulin G (IgG) 3637 (an IgG directed against the IGF-II/Man6P receptor) partially inhibited binding of [125I]IGF-II whereas nonimmune IgG did not. Affinity cross-linking studies with [125I]IGF-II and cardiac myocyte membranes and subsequent analysis of the ligand-receptor complex using SDS-PAGE and autoradiography showed a radiolabeled band of approximately 250 kilodalton (kDa). The formation of the [125I]IGF-II-receptor complex was inhibited by incubation with IGF-II and IgG 3637 but not by insulin or nonimmune IgG. Western blotting of protein extracts from cultured cardiac myocytes was performed using IgG 3637 and an immunoperoxidase technique for the visualization of the IGF-II/Man6P receptor protein. A specific band at 220 kDa under nonreducing conditions was detected on the blots, providing further evidence for the expression of the IGF-II/Man6P receptor by cardiac myocytes. The effect of IGFs on the accumulation of inositol phosphates was measured by HPLC analysis of perchloric acid extracts from myo-[3H]inositol-labeled cultured cardiac myocytes. IGF-I (50 ng/ml) stimulated the accumulation both of Ins(1,4,5)P3 and Ins(1,4)P2 after 30 sec by 43% and 63%. IGF-II (up to 500 ng/ml) had no significant effect on inositol phosphate accumulation under the same conditions. However, in the presence of millimolar concentrations of Man6P, IGF-II (500 ng/ml) also increased Ins(1,4,5)P3 accumulation by 59%. We conclude that cardiac myocytes from adult rats express IGF receptors and respond to IGFs with the accumulation of Ins(1,4,5)P3 and Ins(1,4)P2. This effect seems to be mediated by an IGF-I receptor-specific pathway.
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PMID:Identification and characterization of insulin-like growth factor receptors on adult rat cardiac myocytes: linkage to inositol 1,4,5-trisphosphate formation. 130 23


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