Drugs for Pituitary Thyroid and Adrenal Disorders 03/13/2025

The Endocrine System

• The endocrine system works alongside the nervous system to maintain homeostasis in the body.

• Homeostasis is achieved through hormones produced by various glands, which can have widespread or very specific effects on the body.

• Hormones can be used therapeutically for replacement, treatment of hormone-sensitive cancers, amplification of natural responses, or to block overactive hormone effects.

Homeostasis and Hormones

• Homeostasis: Balance of bodily processes controlled by hormones.

• Hormonal effects:

  • General effects on every cell (e.g., insulin, thyroxine).

  • Targeted effects on specific cells (target cells).

• Negative Feedback Mechanism: Regulates hormone release—when medications are introduced, they can modify this feedback loop.

The Hypothalamus and Pituitary Gland

• Hypothalamus produces releasing hormones that control the pituitary gland:

  • Corticotropin-releasing hormone.

  • Thyrotropin-releasing hormone.

  • Growth hormone-inhibiting hormone.

  • Prolactin-inhibiting hormone.

  • Growth hormone-releasing hormone.

  • Gonadotropin-releasing hormone.

  • Melanocyte-stimulating hormone inhibiting hormone.

• Anterior Pituitary (Adenohypophysis):

  • Produces hormones: ACTH, TSH, Growth hormone, Prolactin, FSH, LH.

• Posterior Pituitary (Neurohypophysis):

  • Stores and releases ADH and oxytocin.

Hormonal Secretion and Disorders

• Glands and their hormones:

  • Adrenal cortex: Corticosteroids.

  • Gonads (Ovaries/Testes): Estrogen, Progesterone, Testosterone.

  • Pancreatic islets: Insulin.

  • Parathyroid: Parathyroid hormone.

  • Pituitary: ADH, Growth hormone, Oxytocin.

  • Thyroid: Thyroid hormones (T3, T4).

• Disorders associated with secretion levels:

  • Hypersecretion: Cushing syndrome (adrenal), Graves' disease (thyroid).

  • Hyposecretion: Addison disease (adrenal), hypothyroidism.

Drug Therapy for Endocrine Disorders

• Examples of treatments for different disorders include:

  • Adrenal Disorders: Ketoconazole, hydrocortisone.

  • Gonadal Disorders: Estrogen, testosterone.

  • Pancreatic disorders: Insulin.

  • Thyroid Disorders: Levothyroxine, methimazole.

Treatment of Hormonal Disorders

• Hypothalamic and pituitary hormones are less commonly used than those acting on target tissues.

• For example:

  • Gonadotropin-releasing hormone: Leuprolide for hormone modulation.

  • Antidiuretic hormone: Desmopressin for diabetes insipidus management.

Thyroid Disorders

• Function: Regulates metabolic rate, growth, and development.

• Thyroid hormones: Made from iodine; include Calcitonin, T4 (Thyroxine), and T3 (Triiodothyronine).

• Disorders:

  • Hyperthyroidism (Graves’ disease) - symptoms include increased metabolism, tachycardia, anxiety.

  • Hypothyroidism (Hashimoto's thyroiditis) - symptoms include weight gain, cold intolerance.

Medications for Thyroid Disorders

• Hypothyroidism Treatments: Levothyroxine, Liothyronine, etc.

  • Potential side effects: weight loss, palpitations, anxiety.

• Hyperthyroidism Treatments: Methimazole, Propylthiouracil, Radioactive iodine.

  • Side effects: N&V, rash, potential liver toxicity.

The Adrenal Glands

• Location: On top of kidneys, consisting of medulla (inner) and cortex (outer).

• Hormones secreted by the cortex:

  • Gonadocorticoids, Mineralocorticoids (aldosterone), Glucocorticoids (cortisol).

• Adrenal insufficiency symptoms: Fatigue, low blood pressure (Addison’s disease).

• Drug treatments for adrenal insufficiency: Various corticosteroids (e.g., hydrocortisone).

Adrenal Excess

• Cushing’s Syndrome: Caused by overproduction of cortisol, leading to common side effects of glucocorticoids.

• Treatment: Focus on underlying causes or inhibiting ACTH secretion.

iClicker Questions

• Identify hormones given orally from hypothalamic and pituitary hormones (e.g., Desmopressin).

• Symptoms of hypothyroidism include dry skin, constipation, fatigue, among others.