REGULATION OF ENERGY METABOLISM

1. Ömer Aslankan
REGULATION OF ENERGY METABOLISM
Complete absorption of an average meal takes around 4 h.
•
Plasma contains circulating glucose, fatty acids, AAs, and other substances to be used by the body's tissues for
•
the production of energy via cell respiration.
The primarily as energy reserves (stores, storage) synthesized after a meal are glycogen and fat; formation is via
•
glycogenesis and lipogenesis, respectively.
proteins act secondarily as energy reserves;
•
e.g; they can be used in muscle contraction, structural strength, enzymatic activity.
•
The formation and use of these reserves are regulated by hormones.
•
Production of circulating energy substrates between meals is via glycogenolysis, lipolysis, gluconeogenesis, and
•
ketogenesis.
Because of differences in cellular enzyme content, different organs have different preferred energy sources.
•
For example; The brain needs blood sugar as an energy source.
•
Skeletal muscles at rest use fatty acids as an energy source.
•
There are two functional states for providing energy for cellular activities and maintaining blood glucose
•
concentration:
Absorptive State: "feasting," when ingested nutrients enter the blood from the GI tract during the 4 h period
•
following a meal
Postabsorptive State: "fasting," after the absorptive state, when the GI tract is empty of nutrients and the body's
•
own stores supply energy