| Sažetak | U regulaciji apetita i održavanju tjelesne homeostaze ključnu ulogu ima mehanizam negativne povratne sprege, koji preko crijevno-moždane osi različitim promjenama i procesima djeluje na žlijezde koje luče određeni hormon u potrebnoj koncentraciji. Mehanizmi gladi i sitosti vrlo su kompleksni te je prisutan veliki broj organa i hormonalnih molekula koje sudjeluju u regulaciji apetita. Ključnu ulogu u regulaciji apetita u mozgu ima hipotalamus u kojemu se nalaze dvije vrste neuropeptida, oreksigeni (apetit-stimulirajući) i anoreksigeni (apetit-inhibirajući) neuropeptidi. Koja će se vrsta neuropeptida lučiti, ovisi o gastrointestinalnim hormonima koji dolaze krvlju iz probavnog sustava kao odgovor na dostupnost ili nedostatak nutrijenata, a taj put ostvaruje se komunikacijom između gastrointestinalnog trakta (GI) i središnjeg živčanog sustava (CNS). Pa tako, u trenutku osjećaja gladi, grelin iz GI trakta krvlju dolazi do hipotalamusa gdje aktivira oreksigene neuropeptide, poput NPY i AgRP, koji onda stimuliraju unos hrane. S druge strane, kada je u organizam unesena hrana, signal sitosti putem anoreksigenih GI hormona kao što su CCK, PYY3-36, PP, leptin, adiponektin, OXM, GLP-1, inzulin, amilin i bombesin, putuje krvlju do hipotalamusa gdje aktivira anoreksigene neuropeptide, POMC i CART, te dolazi do smanjenja unosa hrane. Sama sekrecija GI hormona uvjetovana je i jačinom stimulacije koju makronutrijenti postižu, npr. hormon CCK najviše se izlučuje kada je hrana bogata masnim kiselinama, peptidima i aminokiselinama, dok se sekrecija hormona PYY3-36 povećava kada je hrana bogata proteinima. Na kraju, dotaknut ćemo se poremećaja u sekreciji probavnih enzima koji dovode do naglog razvoja zdravstvenih problema, kao što su pretilost i dijabetes. |
| Sažetak (engleski) | A negative feedback mechanism plays a key role in appetite regulation and maintance of body homeostasis, which through the intestinal-brain ax with various changes and processes affects the glands that secretes a certain hormone in required concentration. Hunger and satiety mechanisms are very complex and there is large number of organs and hormonal molecules involved in the apettite regulation. Key role of apettite regulation in brain has hypothalamus, which contains two types of neuropeptides: orexigenic (appetite stimulating) and anorexigenic (appetite inhibiting). Which kind of neuropeptide will secrete, depends on gastrointestinal hormones coming with blood from the digestive system as a response to availability or lack of nutrients, and this path is achieved by communication between gastrointestinal tract (GI) and the central nervous system (CNS). And so, at the moment of hunger feeling, ghrelin from gastrointestinal tract comes through the blood to the hypothalamus, where it activates orexigenic neuropeptides, such as NPY and AgRP, which then stimulate food intake. On the other hand, when the organism takes food, the signal of satiety through anorexigenic gastrointestinal hormones, such as CCK, PYY3-36, PP, leptin, adiponectin, OXM, GLP-1, insulin, amylin and bombesin, travels with blood to the hypothalamus where it activates anorexigenic neuropeptides, POMC and CART, and stimulates the decrease in food intake. The secretion of gastrointestinal hormones is also dictated by the power of stimulation achieved by the macronutrients, for example the CCK hormone is mostly secreted when the food is rich with fat acids, peptides and amino acids, while the secretion of PYY3-36 hormone increases when the food is rich with proteine. In the end, we will mention the disorders of digestive enzyme secretion that lead to rapid development of health problems, such as obesity and diabetes mellitus. |
