Chylomicron metabolism the exogenous pathway

Chylomicrons Pathway

The metabolism of chylomicrons is often called the exogenous pathway of lipoprotein metabolism. Exogenous means 'from outside the body', since this is the pathway for transporting fat from outside the body - in fact, fat which has been eaten. The pathway is summarised in Fig. 9.2. We have already seen how triacylglycerol and cholesterol are absorbed and re-esterified in the cells of the intestinal wall, and secreted as chylomicron particles, via the lymphatics, into the circulation Section...

Metabolic effects of catecholamines

Catecholamine Effects Urine

Adrenaline and noradrenaline are both amines derived from the catechol nucleus, and the term catecholamines is often used to cover them both (see Fig. 5.10). It will be appreciated that the catecholamines have indirect effects on metabolism which are mediated through 'physiological' changes - heart rate, blood flow, etc. They also have indirect effects mediated through changes in hormone secretion, as well as direct effects in some tissues. In the liver, the catecholamines stimulate glycogen...

The period of adaptation to starvation

Pylori And Species

The changes listed in Table 8.2 come into place gradually over the first three weeks or so of total starvation this is the period of adaptation. Blood glucose concentrations fall very gradually in prolonged starvation and they are followed by the plasma insulin concentration. Glucagon concentrations, on the other hand, rise, so that the ratio of insulin glucagon reaching the liver must change considerably from early to late starvation. The plasma leptin concentration also falls. In longer...

Fat metabolism during endurance exercise

The activity of muscle hexokinase is sufficient, in principle, for all the energy for sustained aerobic exercise to be derived from uptake of plasma glucose. In fact, as we have seen, this would reduce the length of time during which the exercise can be sustained at the highest rate. Simultaneous oxidation of glucose and fatty acids therefore produces the longest possible period of sustained high intensity exercise. The availability of fatty acids to the muscles also reduces the rate of glucose...