Role of Proteins in Insulin Secretion and Glycemic Control - Advances in Food and Nutrition Research - page 4

and release of glucose by the liver, rate of uptake of glucose by peripheral
tissue, and rate of loss and synthesis by the kidney ( Nordlie, Foster, &
Lange, 1999 ). The apparent blood glucose concentration is therefore depen-
dent upon all these factors ( Fig. 1.1 ) .
In the fasted and postabsorptive states, blood glucose homeostasis is
maintained by the regulation of hepatic and renal glucose production and
the amount of glucose taken up predominantly by noninsulin-dependent
tissue (nervous system, red blood cells, skin, smooth muscles, etc.)
( Cherrington, 1999 ) . In the postprandial state, glucose homeostasis is
maintained by controlling the rate of glucose appearance from the digestive
system and the uptake by noninsulin-dependent tissue, peripheral tissue
(skeletal muscle and adipocytes), kidney, and the liver. In the postprandial
hyperglycemic state, hepatic production ceases and tissues exclusively utilize
glucose derived from food ( Moore, Cherrington, &Wasserman, 2003 ) . The
appearance of glucose in the blood is from either exogenous (digestion of
food and absorption) or endogenous (liver and kidney) sources ( Corssmit,
Romijn, & Sauerwein, 2001; Stumvoll et al., 1995 ). The principle

+

Glucagon/adrenal hormones
Insulin/incretins

-
+

-

Brain and nervous system

Liver

Glycolysis and
gluconeogenesis

Energy

Red blood cells

Plasma glucose
concentration

Kidney

Liver

Gluconeogenesis

4-6 mmol/L

Adipose tissue

Storage
and
energy

Glucose
from food

Skeletal muscle

Disposal and
energy

Digestion and absorption Kidney

Food intake

Figure 1.1 A graphical representation of glucose homeostasis.