2.12 Membrane Lipids: Steroid Hormone

• Hormones

  • Biochemical substances produced by a ductless gland that has a messenger function.
  • Serve as a means of communication between various tissues.
• The lipids that play the role of “chemical messengers” include: 

  • Steroid hormone - derivative of cholesterol
  • Eicosanoid - derivative of fatty acids
• 2 major classes of Steroid hormones:

  • Sex hormones - Control reproduction and secondary sex characteristics.
  • Adrenocorticoid hormones - Regulate numerous biochemical processes in the body
• Sex hormones 3 classifications:

  • Estrogen - female sex hormones
  • Androgen - male sex hormones
  • Progestin - pregnancy hormones
• Adrenocorticoid hormone

  • Produced by the adrenal glands
  • 28 Different hormones have been isolated from the adrenal cortex.
• 2 types of Adrenocorticoid hormones:

  • Mineralcorticoids - Control the balance of Na+ and K+ ions in cells
  • Glucocorticoids - Control glucose metabolism and counteract inflammation
• Aldosterone

  • Major mineralocorticoids
  • Serves as the principal regulator of the salt and water balance of the body
  • Synthesized in the body from corticosterone, a steroid derived from cholesterol.
  • In adult humans, about 20–200 micrograms are produced per day
• Cortisol

  • Also known as hydrocortisone
  • A major glucocorticoid
  • Synthesized in the largest amount by the adrenal glands.