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Hormonal stress response

Epinephrine (adrenal medulla) and norepinephrine (nerve endings) are released by the sympathetic nerve system and result in gluconeogenesis, glycogenolysis, lipolysis, and glucagon release (in addition to their hemodynamic effects). Cortisol (release from the adrenal cortex) also leads to gluconeogenesis, adipocyte sensitization (to growth hormone and catecholamines), blocks the antiproteolytic actions of insulin, and also has potent anti-inflammatory effects. The pancreas releases insulin (beta cells) and glucagon (alpha cells), which act in opposition, as well as somatostatin (D cells) which oppose both.

Also note that surgical stress can lead to decreased gonadotropin-releasing hormone release by the hypothalamus (and a consequent hypogonadotropic hypogonadism response). While thyroid-stimulating hormone (TSH) and free T4 are usually normal, serum T3 concentrations and bound T4 may decrease, and reverse T3 may increase, leading to “sick-euthyroid syndrome.”

Stress Response

Increased release of:

– Catecholamines: gluconeogenesis, glycogenolysis, lipolysis, and glucagon release. Increased cardiac output, skeletal muscle blood flow, sodium retention, reduced intestinal motility, cutaneous vasoconstriction, bronchiolar dilatation and behavioral activation.

● Norepinephrine from nerve endings in sympathetic nervous system

● Epinephrine in adrenal medulla

– Cortisol in adrenal cortex anti-inflammatory effects, gluconeogenesis, adipocyte sensitization to growth hormone and catecholamines, block antiproteolytic action of insulin

● Corticotrophin-releasing factor stimulates pituitary to release adrenocorticotropin (ACTH), 8-lipotropin and 3-endorphin

– Vasopressin from paraventricular nucleus of hypothalamus which stimulates ACTH from pituitary, potentiating effect of corticotropin-releasing hormone.

– Insulin from beta cells of pancreas

– Glucagon from alpha cells of pancreas

– Somatostatin from D cells of pancreas

Decreased release of:

– Gonadotropin-releasing hormone from hypothalamus hypogonadotropic hypogonadism

Thyroid hormone changes

– Sick euthyroid syndrome characterized by normal TSH and FT4, decreased T3 and bound T3, increased reverse T3.


  1. Ranabir S, Reetu K. Stress and Hormones. Indian J Endocrinol Metab. 2011;15:18–22. PubMed Link