Secretory Activity Of The Pancreas And The State Of Enzyme Homeostasis In Hypokinesia And Radiation

Abstract

The problem of radiation emissions has acquired particular relevance throughout the world in recent decades. This is due to the widespread use of nuclear energy and radioactive substances, both for military purposes and in many sectors of the national economy in industry, agriculture, medicine, and research institutions. As a result, an increasing number of people are exposed to the harmful effects of ionizing radiation, which often lead to severe and irreversible consequences. [Fedorov V.P. and others., 2010)

The pancreas synthesizes protein at a rate inaccessible to other organs except for the lactating breast, approximately 90% of the secretory protein is produced by acinous cells, and is an enzyme protein. In 1 hour, 20 mg of enzymes are synthesized per dry substance, or 107 enzyme molecules synthesize an acinocyte in 1 min. The pancreatic secret contains enzymes that hydrolyze almost all macronutrients consumed by humans - proteins, lipids and carbohydrates [Korotko G.F. 2017], i.e. they play an important role in digestion. The pancreas participates in enzyme homeostasis by increting and recreating them from the blood [Rotman S.S. 2002].

It is known that the digestive system is one of the most sensitive to the effects of radiation [Saada H.W., et.al ., 2009; Fischer C.J., Yosman P.C., 2008; Kim W.Y., et.al ., 2008], but the pancreas is considered a relatively radioresistant organ, since even at doses causing acute radiation sickness (700-1000 R), there are no significant morphological changes in it.  A decrease in the secretion of pancreatic enzymes during in vivo irradiation may be the result of a weakening of stimulating effects at the level of their generation, as well as the conduction of signals in the chain of neurons of the meta-sympathetic ganglia of the gland [Yameguchi K. et.al ., 2000; Telbsz A., Kovacs A.L., Somosy Z., 2002], as well as the result of inhibition of neurohumoral regulation processes expressed in a violation of the balance of adrenergic and cholinergic regulation in the gastrointestinal tract , the predominance of destructive processes .. 

   A decrease in physical activity and an increase in a sedentary lifestyle is a fundamental problem of modern medicine. Inactivity and hypokinesia, which leads to a stressful state, also adversely affects the functional activity of all organs and systems of the body, reducing overall resistance, lowering the natural mechanisms of its resistance. [Ivanauskene N.Yu., 2000; Izatulin A.V., et al., 2005].

Constant muscle activity is vital not only for the normal function of most systems and organs, i.e. the effector, but also the central nervous system. It is in the motor analyzer that all cortical afferences converge and converge, not only proprioreceptive, but also exteroreceptive and interoreceptive.

The changes observed from the digestive system in human and animal hypokinesia are combined by one concept, "hypokinetic syndrome of the digestive system." Changes in the activity of the organs of the gastrointestinal tract in hypokinesia are secondary. They depend mainly on the duration of the deficiency of activity leading to a decrease in energy consumption, bioenergetics and structural metabolism in the muscles, and a weakening of tonic impulses from the muscles. The use of radiation for therapeutic purposes in patients in bed rest creates the possibility of a combined effect of hypokinesia and radiation on humans. However, the patterns of the biological effect of radiation on the body in conditions of limited motor activity have not been sufficiently studied.