Physiological Effects of Cortisol

Normal circulating levels of cortisol, including the circadian early-morning rise and the moderate elevations after meals and minor stresses, help sustain basic physiological (vegetative) functions. Large amounts of cortisol released in response to major stresses enable the individual to withstand, or cope with, the metabolic, cardiovascular. 

Cortisol induces and maintains the activity of all of the specifically gluconeogenic enzymes in the liver. 

Cortisol inhibits glucose utilization in peripheral tissues, such as skeletal muscle, adipose tissue, bone matrix, lymphoid tissue, and skin, by inhibiting glycolysis and promoting the use of fatty acids. This action is modulated by insulin and thyroid hormones but is potentiated by GH. 

Cortisol promotes the liberation of fatty acids from adipose tissue by inducing and maintaining the synthesis of hormone-sensitive lipase (HSL), an effect supported by GH. The actual activity of HSL is controlled by those hormones that trigger its phosphorylation (glucagon, catecholamines) or dephosphorylation (insulin, PGE). 

Cortisol, by inhibiting glucose utilization in peripheral tissues, exerts a mild antianabolic effect on these tissues this effect diminishes their rate of amino acid incorporation, thus making available more amino acids for metabolism by these tissues, but mainly for hepatic protein synthesis and gluconeogenesis. 

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The biochemical and physiological effects of cortisol are snmmarised in Figure 12.10. Higher than normal concentrations of cortisol improve mood and reduce the activity of the immune system. Hence, they are routinely used to reduce chronic inflammation. There are, however, side-effects of these high levels increased levels of blood glucose, obesity and retention of water giving rise to moon face . 

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