A Simple Free Fat Cell Bioassay for Insulin

Moody, A. John; Ma, Stan; Stan, Miriana; Gliemann, Jørgen

doi:10.1055/s-0028-1093895

Cited by 373 publications

(178 citation statements)

References 0 publications

Supporting

Mentioning

177

Contrasting

Unclassified

Order By: Relevance

“…Incubations were terminated by the addition of 5 ml of a toluenebased scintillant to each reaction vessel. Incorporation of 3H-glucose into cellular lipid (a reliable indicator of glucose transport under these conditions) was determined by liquid scintillation counting following overnight phase-separation at 4~ Under these assay conditions, the radioactivity associated with water-soluble molecules (including unincorporated 3H-glucose) is not counted to a significant degree [40].…”

Section: H-glucose Incorporation Into Lipid Adipocytes Were Isolatedmentioning

confidence: 99%

Expression of human GLUT4 in mice results in increased insulin action

Deems¹,

Evans²,

Deacon³

et al. 1994

Diabetologia

View full text Add to dashboard Cite

Summary Glucose metabolism was evaluated in transgenic mice expressing the human GLUT 4 glucose transporter. Fed GLUT 4 transgenic mice exhibited a 32 % and 56 % reduction in serum glucose and insulin and a 69 % and 33 % increase in non-esterified fatty acid and lactate levels, respectively. Transgenic mice exhibited a significant increase in whole-body glucose disposal during a euglycaemic-hyperinsulinaemic clamp. Insulin-stin'mlated glucose uptake in isolated soleus muscles and adipocytes was greater in transgenic compared to control mice due to increased basal glucose uptake. Transgenic mice displayed increased glycogen levels in liver and gastrocnemius muscle, and increased insulin-stimulated 14C-glycogen accumulation in isolated soleus muscle. We conclude that over-expression of the GLUT 4 glucose transporter in mice results in 1) an increase in whole-body glucose disposal and storage, and 2) an increase in both basal and insulin-stimulated glucose uptake and disposal in vitro. These changes resulted in the reduction of serum glucose and insulin levels. These results provide direct evidence that glucose transport (and GLUT 4 per se) plays a significant role in regulating wholebody glucose homeostasis. Additionally, these data support the idea that pharmacological strategies directed at increasing the expression of GLUT 4 protein may have beneficial (hypoglycaemic) effects in the diabetic state. [Diabetologia (1994[Diabetologia ( ) 37: 1097[Diabetologia ( -1104

show abstract

Section: H-glucose Incorporation Into Lipid Adipocytes Were Isolatedmentioning

confidence: 99%

Expression of human GLUT4 in mice results in increased insulin action

Deems¹,

Evans²,

Deacon³

et al. 1994

Diabetologia

View full text Add to dashboard Cite

show abstract

“…The biological activity of the derivatives was determined as described by Moody et al (1974) Table 1 shows the sources and biological potencies in vitro of the insulin derivatives studied.…”

Section: Preparation Ofinsulin and Its Derivativesmentioning

confidence: 99%

Binding of insulin to bovine liver plasma membrane. Use of insulin analogues modified at the A1 residue

Rösen

Simón

Reinauer

et al. 1980

Biochemical Journal

View full text Add to dashboard Cite

Bovine liver plasma membranes [Rosen, Ehrich, Junger, Bubenzer & Kuhn (1979) Biochim. Biophys. Acta 587, 593-6051 show similar insulin-binding characteristics, as evaluated by Scatchard analysis, to those of membrane systems from other species. However, the dissociation rate of bound insulin cannot be accelerated by the addition of insulin, in contrast with membranes isolated from rat liver. The dissociation rate is strongly dependent on the pH. Although dependent on temperature, the total capacity of binding sites is minimally changed, but the number of high-affinity sites is increased 2-3-fold, by lowering the incubation temperature. These data might be interpreted by assuming a single population of receptors whose distribution between different affinity states depends on temperature. In competition studies, most of the modified insulins examined show a close correlation between binding, determined i'n plasma membranes from bovine liver, and biological activity, measured in adipocytes. The hypothesis that a positive charge on the Al residue may be favourable for binding is supported by experiments with an isosteric pair of insulins modified at this residue ([carbamoylGlyAl]-and [amidino-GlyAllinsulin) and with modified insulins carrying one or more positive charges on the Al residue ([Arg-GlyAl1-, [Arg-Arg-GlyAl1-, [Arg-ArgArg-GlyAl1-and [Lys-Arg-GlyAl]insulin). The latter insulin derivatives show a higher binding activity for plasma membranes from bovine, porcine and rat liver than expected from their biological activities in adipocytes.

show abstract

“…antibodies. The purity of the insulin fraction wasjudged by its homogeneity on PAGE incubated for 90 min at 37 "C. At the end of the incubation time the reaction was terminated by the addition of toluene scintillant [24].…”

Section: Test For Biological Activitymentioning

confidence: 99%

Dogfish insulin

Bajaj

Blundell

Pitts

et al. 1983

European Journal of Biochemistry

View full text Add to dashboard Cite

Insulin from an elasmobranch, the spiny dogfish (Squalus acantlzias) has been purified to near homogeneity by means of acid-ethanol extraction and salt precipitation. The amino acid sequences of the performic-acid-oxidised A and B chains have been determined and exhibit some unusual features. The A chain contains a total of 22 amino acids; only the insulin from coypu (a member of the Rodentia suborder, Hystricomorpha), has previously been reported to contain an extension past the A,, asparagine. The B,, histidine, which is involved in the formation of the insulin hexamers in higher vertebrates through the co-ordination of zinc, is present in this elasmobranch insulin. Several substitutions relative to bovine insulin occur in the proposed receptor binding region (A,Gln+ His, B, Glu +Pro, B,,Arg+Lys, B,,Phe+Tyr). In spite of these substitutions, the maximal response in the rat epididymal fat cell assay is the same for bovine and dogfish insulins; the concentration required to produce the half-maximal response is, however, approximately threefold greater for dogfish insulin than that of bovine insulin.The use of interactive computer graphics model-building predicts that the dogfish insulin can attain a threedimensional structure very similar to that of bovine insulin; circular dichroic spectra are presented which support the model-building studies.In the years since the determination of the amino acid sequence of bovine insulin [I] and the subsequent elucidation of the three-dimensional structure of the protein hormone [2], many insulins from different species have been studied. These investigations have attempted to corrclate the physical and biological properties of the hormone to specific amino acid residues in the sequence [3,4], as well as to understand thc evolution of the hormone [5,6].Immunocytochemical and biological studies suggest the presence of an insulin-like activity in prokaryotes such as Escherichia coli K12 [7], in various unicellular eukaryotes [S], in the protostomian [9] and the deuterostomian [lo] lines of invertebrate evolution [5]. However, the complete chemical characterization of these insulin immunoreactivities has not yet been possible. Though representative insulin sequences from teleosts reptiles, aves and mammals, are available, 21 lack of information exists at the level of lowermost gnathastomian vertebrates, namely the cartilaginous fish [5].Insulin from the hagfish (Myuine glutinosa) a jawless fish, is the phylogenically most original insulin to be scqucnced [5,1 I]. X-ray analysis [I21 suggests that this insulin has a spatial structure very similar to porcine insulin, even though the cyclostomian line seems to have diverged from the main line of vertebrate evolution nearly 500 million years ago [13]. Hagfish insulin has a very low biological potency when assayed in mammalian systems. Further it lacks the histidine at B,, which is responsible for the formation of zinc-insulin hexamers in most mammalian insulins. In contrast, several teleost insulins that have been studied can for...

show abstract

A Simple Free Fat Cell Bioassay for Insulin

Cited by 373 publications

References 0 publications

Expression of human GLUT4 in mice results in increased insulin action

Expression of human GLUT4 in mice results in increased insulin action

Binding of insulin to bovine liver plasma membrane. Use of insulin analogues modified at the A1 residue

Dogfish insulin

Contact Info

Product

Resources

About