Hot answers tagged

11

In short, because the easiest way to get the protein coding sequence of the gene is to create cDNA based on the mRNA, and insulin mRNA is only expressed in pancreatic cells. Insulin gene consists of two exons. That means, amplifying the genome will not give us a coding sequence -- two pieces of that sequence will be interrupted by a large, non-coding intron....


9

Blood sugar drops (Hypoglycaemia) There are several other uses of insulin (other than diabetic treatment) Some of those could be: Diagnostics Psychology (Narcoanalysis) Parenteral nutrition Cardiology (Glucose–insulin–potassium solution (GIP or GIK solution) is given after a myocardial infarction) Malignancy (Insulin potentiation therapy (IPT)) ...


7

Is the standard Lotka-Volterra (LV) model an exact fit for insulin-glucose (IG) dynamics? No. Can a similar model built on the same principles capture most of the essential features of the IG dynamics? Absolutely. How to capture most of the insulin-glucose dynamics using a slightly modified Lotka-Volterra model We can figure out how to change the LV ...


6

Glucagon needs glucagon receptors to have an effect on the tissue or organ in question, and your answer can be found there. Glucagon receptors are found in the liver, like you say, but they're also found in other tissues like intestinal smooth muscle, and brain tissue (http://www.glucagon.com/glucagonreceptor.html) - but, crucially, not in skeletal muscle. ...


6

There are a couple of reasons why this approach doesn't work quite as well as you might hope. First, insulin doesn't go away after a high-fat meal. This paper reports changes in serum insulin following pure-sugar and pure-fat meals. Although there is much less of an increase in insulin following the pure-fat versus the pure-sugar meal, you will notice in ...


4

Summary The whole point of hormones is that they allow the organism to control the metabolism of tissues in an integrated manner, rather than each tissue acting independently. Insulin, glucagon and epinephrine are classic examples of this in relation to carbohydrate metabolism. In the fed state, the fasted state and in stress situations it is appropriate ...


3

Human Embyronic Stem Cells (hESC) can be programmed to differentiate into a number of different types of tissue depending on the signals you give or withhold. Source: BioTime The company Viacyte is actually developing a technology based on hESC that can be used to rescue loss of function in type-1 diabetes, just as an example. Their process takes hESC to ...


3

Great Question. The biggest problem is persistent insulin signaling from prolonged excessive high blood glucose over time. The reason being that it is this kind of signaling that results in insulin insensitivity due to down-regulation of the insulin receptors. Any bolus of carbohydrates > ~ 25grams in a sitting is going to bump up blood sugar at a fast ...


3

Insulin is processed from proinsulin by folding the peptide and forming 3 disulfide bonds before cleaving the peptide in 2 positions, leaving 2 peptide chains held in place by the disulfide bonds. This process is summarized in this image: This only works because the peptide is packaged in a secretory vesicle during synthesis. This protects the peptide ...


2

Interpreting your question as "would the Lotka-Volterra predator-prey model be a good model for the glucose-insulin system?" my answer is "no". The predator-prey equations capture assumptions about how prey and predator interact with each other, and how they would fare on their own. These assumptions are not equivalent to any reasonable assumptions about the ...


1

Technically you can link two proteins together, but why would you want to do this? Antibody drug-conjugates are used to specifically target cells which can be differentiated from the healthy cells by their cancer neoantigens. This provides a high specificity of the drug delivery and also limits side effects on healthy cells. For insulin on the other hand ...


1

Concluding from this 1991 PubMed article, intravenous (or subcutaneous) insulin may not stimulate glycogen synthesis more than naturally secreted insulin. Experiments carried out in man have suggested that insulin may play only a permissive role in the determination of splanchnic glucose uptake. In a study by DeFronzo et al. (5), in which the plasma ...


1

Yes, the insulin receptor can be viewed as an enzyme, since it catalyzes a reaction -- phosphorylation of tyrosine residues on its substrates. But since the protein has multiple functions, it's probably better to say that the insulin receptor "has enzymatic activity", rather than "is an enzyme". The notion "enzyme" is not restricted to catalysis of ...


1

On the Ensembl website you can find an easy way to compare genetic sequences of the available genome references, including the one of several primates. Here a query example: http://www.ensembl.org/Homo_sapiens/Gene/Compara_Alignments?align=822&db=core&g=ENSG00000254647&r=11%3A2159779-2161341 For protein sequences, check the Uniprot website. For ...


1

Insulin, like glucagon, binds to receptors on the surface of muscle cells and illicits a response that is transduced to produce changes of phosphorylation in the enzymes controlling glycogen turnover. Unlike glucagon it does not initiate an enzyme phosphorylation cascade, but its binding to the receptor causes autophosphorylation on tyrosine residues, ...


1

Your question doesn’t make it clear whether you think that the pancreas must be under the control of the hypothalmus, or whether you are asking whether it has an influence on the pancreas in relation to the secretion of insulin and glucagon, which control the concentration of blood glucose. First, it has been long known that secretion of insulin can be ...


1

It is possible to overdose and die of an insulin injection. Obviously, if enough is injected fast enough, the body can't recompense appropriately and and the person would die of hypoglycaemia. Below around 20mg/dL of blood sugar levels in the blood you are likely to suffer brain damage and eventually death.


1

No, the Lotka-Volterra model is a description of predator-prey dynamics. Although in some respects over-simplifying it is well suited for educating population dynamics and basic research. The physiology of carbohydrate homeostasis is different. Although, similar to population count in the Lotka-Volterra model, the elimination of both glucose and insulin ...


Only top voted, non community-wiki answers of a minimum length are eligible