Course code: vbb 301 course title: Biochemistry of Hormones & Disease number of units

METABOLIC ROLE OF GLUCOCORTICOIDS 
1. Metabolic Actions: 
Points to note: 
 
In general, glucocortidoids have anti-insulin effects 
 
Glucocorticoids are catabolic to peripheral tissues and anabolic to liver. 
a. Effects on carbohydrate metabolism: overall effect increases blood glucose level 
(hyperglycaemia) 
Mechanism of hypergly aemia 
1. Decreases glucose uptake; and utilization in muscles, in adipocytes and lymphoid cell by 
inhibiting the membrane transport of glucose into these cells. 

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2. Enhancing gluconeogenesis in liver: induces the synthesis of key gluconeogenic enzymes 
such as pyruvate carboxylase, PEP carboxykinase, fructose 1, 6-diphosphatase and also 
glucose-6-phosphatase. 
 
By making available more of substrate required for gluconeogenesis. This is achieved 
by
 
Increasing protein catabolism in extrahepatic tissue 
 
Decreasing incorporation of amino acids in protein in peripheral tissues. 
 
Also increasing synthesis of some key enzymes required for amino acid catabolism 
like alanine transaminase, tyrosine transaminase, tryptophan pyrollase. 
3. Decreases glycolysis in peripheral tissues
 
In liver: glucocorticoids are anabolic. It increases the glycogen store in liver. This is 
due to: 
 
Increases in gluconeogenesis from amino acid and glycerol 
 
Activates protein-phosphatase-1 which dephosphorylates and activates glycogen 
synthesis: 
 
Stimulate the synthesis of glycogen synthase also 
b. Effect on lipid metabolism: Net effect increase FFA in plasma and also glycerol. Glycerol 
is utilized for gluconeogeneris in liver. 
In adipocytes. 
 
Glucocorticoids increase lipolysis and liberates FFA and glycerol by activating 
hormone sensitive TG lipase. 
 
As glucocorticoid decrease the uptake of glucose in adipose tissue, there will be 
reduction in α-glycerol phosphate as a result esterification suffers, hence net flow of 
FFA in plasma increase. 
c. Effect on protein metabolism 
 
In peripheral extrahepatic tissues, cortisol is catabolic and increase protein 
breakdown, leading to increase amino acids availability in plasma.
Reasons of increased catabolism 
 
Enhances synthesis of key enzymes of amino acid catabolism like transaminase, 
tyrosine transaminase 
Tryptophen pyrrolase etc 
 
Also there is decreased incorporation of amino acids in protein molecule 
 
In liver: cortisol is anabolic, it increases protein synthesis it increases; 
 
Hepatic uptake of amino acids 

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 
Incorporation of amino acids into ribosomal proteins. 
 
Increased m-RNA formation and synthesis of proteins including plasma protein 
 
In liver, cortisol also enhances urea synthesis from amino acids. There is increased 
synthesis of enzymes necessary for urea cycle, e.g arginino succinate synthetase, 
arginase etc.