Hormonal Response to Exercise (1)

Adrenal medulla

-not of epithelial origin

-composed of mostly chromaffin cells that are modifies sympathetic neurons

-releases catecholamines

Catecholamines

-bind to adernergic receptors (GCPR-G coupled protein receptors)

Adrenal Cortex

-of epithelial origin

-secretes steroid hormones all originating from cholesterol: aldosterone, cortisol, androgens and estrogens

Aldosterone

-involved in maintenance of Na+/K+ balance (consequently O2 balance) —>Na+ reabsorption and K+ secretion

2 primary stimuli for aldosterone

1.increased [K+]

2.decreased blood pressure (RAAS pathway)

Cortisol

-promotes breakdown for gluconeogensis iin liver

-stimulates FFA mobilization

-limits uptake of glucose into cells (that use GLUT-4) and so may promote the use of FFA as fuel

Pancreas

serves both exocrine and endocrine function

exocrine secretions: bicarbonate and digestive enzymes

endocrine functions: performed by islets of Langerhans and release: somatostatin, insulin and glucagon

Somatostatin

-released by delta cells (10% of islets of langerhans)

-released during abosrptive state—>inhibits pancreatic exocrine function to lower gastric emptying rate

-also inhibits glucagon release