Hormones and Lipid Metabolism

Lipid Metabolism and Glucocorticoids

• Glucocorticoids inhibit lipogenesis, favoring fat mobilization from adipose tissues.
• In large amounts, they promote redistribution of fat from extremities to central body regions, leading to "moon face" and "buffalo hump" formation.

Sex Glands and Hormones

• Sex glands (ovaries and testes) produce sex cells and hormones essential for sexual characteristic development and reproductive apparatus maintenance.
• Testosterone, produced by male sex glands, promotes:
  • Male reproductive tract growth and function
  • Male secondary sex characteristics (deep voice, facial hair)
• Estrogens, produced by female sex glands, contribute to:
  • Female secondary sex characteristics
  • Mammary gland development
  • Onset of menstruation and reproductive organ development
• Progesterone, produced by female sex glands, assists in normal pregnancy development.

Thymus Gland

• The thymus gland is located in the upper chest above the heart.

Growth Hormone (GH)

• GH increases protein synthesis and nitrogen retention.
• GH stimulates:
  • Lipid mobilization and utilization from adipose tissue
  • Hepatic glucose output (gluconeogenesis)

Prolactin (PRL)

• Prolactin secretion is suppressed by dopamine.
• Prolactin:
  • Initiates and maintains milk secretion from breasts
  • Inhibits gonadotropin effects and may prevent ovulation in lactating women

Follicle-Stimulating Hormone (FSH)

• FSH secretion is stimulated by GnRH.
• FSH:
  • Directly stimulates spermatogenesis in male testicular seminiferous tubules
  • Stimulates follicular growth and development in female ovaries

Luteinizing Hormone (LH)

• LH secretion is stimulated by GnRH.
• LH:
  • Stimulates testosterone production in male testicular interstitial cells
  • Promotes maturation of ovarian follicles and estrogen secretion
  • Induces ovulation and corpus luteum formation

Thyroid-Stimulating Hormone (TSH)

• TSH secretion is stimulated by TRH and cold.
• TSH:
  • Maintains thyroid gland structural integrity
  • Promotes thyroid hormone synthesis and release (T3 and T4)

Adrenocorticotropic Hormone (ACTH)

• ACTH secretion follows a diurnal circadian rhythm with peak production in the early morning.
• ACTH:
  • Is inhibited by elevated plasma free glucocorticoid (cortisol) levels

Hormones of the Neurohypophysis

Antidiuretic Hormone (ADH; Vasopressin)

• ADH secretion is promoted by:
  • Reduced extracellular fluid (ECF) volume
  • Pain, emotional stress, and certain pharmacologic agents
• ADH:
  • Regulates extracellular fluid volume and osmolality by controlling urine volume and concentration