EXERCISE AND MECHANISMS OF BLOOD GLUCOSE REGULATION

Öz

During exercise, as the amount of intramuscular glycogen is insufficient to meet the glucose demands of skeletal muscles, the uptake of blood glucose increases. In this process, blood glucose homeostasis is maintained through glycogen breakdown (glycogenolysis) in the liver and the production of glucose from lactate, glycerol, and amino acids (gluconeogenesis). Various feedforward and feedback mechanisms regulate hormone secretions (with increased secretion of cortisol, epinephrine, growth hormone, norepinephrine, and glucagon, and decreased insulin secretion), resulting in glucose release from the liver. This glucose is then transported into skeletal muscle in proportion to its release via GLUT4, ensuring the provision of glucose necessary to meet the energy demands of the muscle while maintaining blood glucose homeostasis.

Anahtar Kelimeler

• Exercise
• Gluconeogenesis
• GLUT4
• Blood glucose metabolism

Egzersiz ve Kan Glikozu Düzenleme Mekanizmaları

Öz

Egzersiz sırasında iskelet kaslarının glikoz ihtiyacına kas içi glikojen miktarı yeterli olmadığı için, kan glikozu alımı artmaktadır. Bu süreçte kan glukozu homeostazı karaciğerde glikojen yıkımıyla glikoz (glikojenoliz) ve laktat, gliserol ve amino asitlerden glikoz üretimi (glukoneogenez) ile sağlanır. Çeşitli ileri ve geri bildirim mekanizmalarıyla, hormon salınımları (kortizol, epinefrin, büyüme hormonu, norepinefrin ve glukagon salınımı artar, insülin salınımı azalır) düzenlenir ve karaciğerden glikoz çıkışı meydana gelir. Glikoz çıkışıyla orantılı bir şekilde iskelet kasından GLUT4 aracılığıyla kas içine trasnportu gerçekleşir. Böylelikle hem kastaki enerji ihtiyacının karşılanması için gerekli olan glukoz sağlanır hem de kan glukozu homeostazı devam ettirilir.

Anahtar Kelimeler

• Egzersiz
• Glukoneogenez
• GLUT4
• Kan glikoz metabolizması

Kaynakça

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