American neurophysiologists have published the experimental results which may lead to a definite revision of traditional thoughts of the insulin’s functioning in the human organism and of the mechanism of emergence of neurodegenerative diseases. This work has been made by the researchers of a small but extremely elite private University of Brown (BrownMed) situated in Providence, the capital of Rod-Island State.

 

It is well known that insulin plays a key role in many processes that govern the energetics of live cells. This albuminous hormone makes cell membranes of internal lining of blood vessels more glucose penetratible and thus favors its transition from the blood to several tissues. When insulin “works” inside the muscles it stimulates the transition of glucose into polysaccharideglycogen, which is a most important reserve source of biochemical energy. In liver’s tissues insulin, in contrast, curbs glycogen’s decomposition, and thus suspends the appearance of sugar. Also insulin regulates the transformation process of carbohydrates into fat acids, which in their turn, are a raw material for the synthesis of fats. Altogether, insulin is an actually universal hormone of anabolism, a complex of the processes, which lead to the synthesis of compound molecules from simpler ones and to the accumulation of chemical energy.

 

Insulin was discovered as far back as in the beginning of the twenties of the last century. Over the last 80 years scientists might have had enough time for detailed study of the mechanisms of its production and utilization inside the human organism. It is well known that each hormone produces an internal secretion gland. It is written in textbooks that there are specialized cells of pancreas which are called insular Langergans beta-cells. The cell of some individuals practically don’t work, as a result there is no production or scarce production of insulin in their organisms. Such people are condemned to the serious disease, diabetes of the 1 st type, which develops in their childhood and youth. But more often it happens that the organism does not duly react to the insulin which the pancreas supplies in normal quantity or even in surplus. In this case glucose still accumulates in the blood and later in the urine and after a period of time there emerge typical symptoms of another form of saccharine disease, which is known as diabetes of the 2 nd type.

 

What’s the news that has ever brought to light Susanne de la Monte, Pathology Professor, and her colleagues? Experimenting on rats, they found out that insulin was produced by beta cells of pancreas, but also by neurons of some parts of the brain. If this result proves true it will be acknowledged as a finding of primary importance, because so far it has occurred to nobody that the brain may be a source of insulin. The scientists from Providence also have found out that the same neurons synthesized the two albumins which regulate many processes of cell division. In terms of their chemical structure these proteins have much in common with insulin, that is why they are called insulinoid growth factors of the 1 st and the 2 nd type (do not confuse with analogous types of diabetes!). It appeared that the brain cell produce insulin and this couple of albumins for the simple reason that these matters are important for survival and normal work. Deficit of “intracerebral” insulin and insulinoid growth factors turns into death of neurons of frontal lobes of the cortex of big hemispheres together with hippocamp and hypothalamus. It is well known that these parts of the brain are the first to suffer in the course of Alzheimer disease.

 

What are the conclusions of the scientists of Professor de la Monte’s team? From one hand they do not exclude that their work may mean a finding of a before unknown form of diabetes exclusively affecting brain tissues. Without overintellectualizing the co-authors propose to call this disease diabetes of the 3d type. But from the results of their experiments they have made one more conclusion - much more important one. It is well known for a long time that an insulin subnormal sensitivity - a characteristic feature of diabetes of the 2 nd type - someway (not yet clear how) increase the risk of emergence of neurogenerative pathologies, in the first place Alzheimer disease. And now it has occurred that the slowdown of intracerebral insulin and insulinoid growth factors kills the cells of the parts of the brain which are affected in the course of this disease. Professor de la Monte thinks that this result may mean that a newfound diabetes of the 3d type and Alzheimer disease are actually the same neuroendocrinic disease which have much in common with a “normal” diabetes. If this new understanding of the nature of Alzheimer disease is acknowledged true, it, without any doubt, will help in the search of methods of its treatment.

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