Problems Associated with the Pituitary Gland Nick Pytel Nate Mohney
The Endocrine System What are some of the structures associated with the endocrine system?
The Endocrine System • What are some of the structures associated with the endocrine system? • Pituitary Gland • Pineal Gland • Thyroid & Parathyroid Glands • Thymus • Adrenal Glands • Pancreas • Ovaries (females) • Testes (males)
The Endocrine System What is the major function of the endocrine system?
The Endocrine System • What is the major function of the endocrine system? • To maintain Homeostasis
The Endocrine System What are some of the processes regulated by the endocrine system?
The Endocrine System • What are some of the processes regulated by the endocrine system? • Hydration (Post. Pituitary) • Metabolism (Thyroid) • Electrolyte Levels (Thyroid, Parathyroid, Adrenal) • Blood Sugar Levels (Pancreas, Adrenal) • Fight or Flight Response (Adrenal) • Reproduction (Ovary, Testis, Pituitary) • Growth (Pituitary, Thyroid) • …and many more
The Endocrine System How does the endocrine system regulate these processes?
The Endocrine System • How does the endocrine system regulate these processes? • Through chemical signals known as Hormones Human Testosterone Human Insulin Human Growth Hormone
The Endocrine System What is known as the “Master Gland?” Why is it called this?
The Endocrine System • What is known as the “Master Gland?” • The pituitary gland • Why is it called this? • It is one of the most proximal endocrine glands to the brain • It’s hormones regulate those of other endocrine glands
The Pituitary Gland • Remember that the anterior pituitary gland • is highly vascularized • contains many epithelial cells that secrete hormones • nerves from the hypothalamus stimulate the pituitary cells to release their hormones • Secretes several different hormones, but the two we will discuss are • Growth Hormone (GH) also known as somatropin • Adrenocorticotropic Hormone (ACTH) aka corticotropin
Human Growth Hormone • Human Growth Hormone (aka somatotropin) • Indirectly stimulates the growth of muscle, bone, and other tissues • Acts on the liver, which releases somatomedins that directly affect: • Chondrocytes → Cartilage Formation → Bone Growth • Muscle Cells → Protein Synthesis → Muscle Growth • Fat Cells → Lipogenesis Triglyceride Structure
Human Growth Hormone Negative Feedback • Operates by Bone Muscles Hypothalamus Fat Somatocrinin (Growth Hormone Releasing Hormone –GHRH) Somatomedin Growth Hormone (Somatotropin) Anterior Pituitary Liver
Adrenocorticotropic Hormone • ACTH stimulates the adrenal cortex to produce corticosteroid hormones including cortisol Hypothalamus Corticotropin Releasing Hormone (CRH) Adreno-corticotropic Hormone (ACTH) Anterior Pituitary
Cortisol • Cortisol is produced by the Suprarenal Glands in response to ACTH secretions • It is usually produced in response to stress • fasting, psychological (depression, fear, stress), prolonged exercise, hypoglycemia, and illness • It promotes gluconeogenesis • the production of glucose from lipids, glycogen, and proteins (which are broken down to fatty acids, glucose, and amino acids respectively) • Raise blood glucose levels to replenish depleted supplies • Prolonged secretion causes hyperglycemia
Cancer • The basis of cancer is when structural damage to the DNA sequence of a cell compromises the control of cell growth a division • Often requires damage to multiple genes that regulate cell division • The result is the cell proliferates uncontrollably • Causes include random DNA replication errors as well as damage to the DNA sequence (UV light, X-rays, chemical carcinogens)
The Forms of Cancer • Benign Tumors • generally, uncontrolled cell proliferation begins in this way • are limited in growth by the presence of surrounding tissue • are made up of cells that are bound to one another and do not metastasize What problems may arise from benign tumors?
The Forms of Cancer • Pressure • A growing mass may put pressure on the surrounding organs: closing vessels and straining organs • Metastasis • The increased rate of division correlates to an increased rate in DNA replication errors, which may lead to loss of intercellular binding function • Lead to malignant tumors (cancer) • Adenomas • Particularly in tissue that secretes regulatory hormones, an increase in the number of cells would lead to an imbalance in hormone secretion.
Pituitary Adenomas • Adenoma – A benign epithelial neoplasm in which the tumor cells form glands or gland-like structures • Types of Pituitary Adenomas • Prolactinoma - Most Common - ~43% • Non-Secreting - ~30% • Growth Hormone Secreting - ~17% • ACTH Secreting - ~7% • TSH Secreting - ~3% • All Others… Rare
GH Oversecretion • Gigantism – Abnormal size or overgrowth of the entire body or any of its parts. • Abnormally large stature • Proportional • Before growth plates close in long bones 12 year old kid with his mother
GH Oversecretion • Acromegaly – Disorder resulting in progressive enlargement of face, hands, feet and soft tissues. • Occurs after growth plates have closed • Disproportionate growth Woman suffering from acromegaly at ages 16, 33, and 52. What changes do you notice?
Living with Acromegaly • Severe Headaches • Arthritis and Carpal Tunnel Syndrome • Diabetes Mellitus • Renal Failure • Enlarged Heart and Hear Failure Shortened life span and diminished quality of life! What are some potential treatments?
Treatments for Acromegaly • Surgery – Transsphenoid • Medication – • GH Inhibitors with supplemental GH • Radiation • Possible side effects?
Cushing’s Syndrome • Collection of symptoms derived from long term overexposure to cortisol • Cortisol is a key hormone in the body’s response to stress • Pituitary adenomas are most common cause – Cushing’s Disease • 5x more common in women
Symptoms of Cushing’s • Increased central body fat – head, neck, torso • Moon face • Skin ulcerations • Buffalo hump • Immunosuppressed • Growth suppression (In children) • Mood changes (Depression) • Purple Straie
Diagnosis for Cushing’s • 24-Hour Urine Free Cortisol Level • Measure of how much cortisol is excreted via urine in a 24 hour period. • Normal range for adults… <100 micrograms/day • Positive test can be up to several times higher • What might interfere with the results?
Cushing’s Treatment If it is caused by a pituitary adenoma then the treatment is very similar to the treatment for acromegaly. • Surgical removal of tumor • Irradiation of tumor • Medications to inhibit tumor secretions or limit the effectiveness of the synthesis pathway
But What if There’s Too Little Hormone? • Too little Growth Hormone leads to pituitary dwarfism • Too little ACTH leads to Addison’s disease
Pituitary Dwarfism • Severely stunted growth • Proportional development • Treated with regular hGH injections • If treatment starts early the patient can achieve a near normal stature
Addison’s Disease • Symptoms • Fatigue • Weight Loss • Weakness • Dizziness • Hyperpigmentation • Treated with hormone replacement therapy. Fun Fact: Do you know someone famous who had Addison’s?