Pharm - Hypothalamic & Pituitary Flashcards
How do the connections between the hypothalamus and the anterior and posterior pituitary differ?
The hypothalamus communicates with the anterior pituitary via vascular supply, whereas it communicates with the posterior pituitary via axonal projections
Describe how the control and action of prolactin is different than the other Hypothalamic/Pituitary hormones
Prolactin does not have a corresponding releasing hormone from the hypothalamus like the other hormones does. Prolactin acts directly on target tissues instead of stimulating hormone release from a peripheral gland.
What are the 5 endocrine axes?
HPL: growth hormone HPT: thyroid stimulating hormone HPA: ACTH HPG: LH and FSH Prolactin
Which hormones act through a JAK/STAT pathway?
Prolactin and Growth hormone
Describe the feedback that tightly regulates most hypothalamic/pituitary hormones
End products cause negative feedback through long, short, and ultrashort loops. This feedback shuts down the axes in order to maintain stable levels of hormones.
How does GH affect muscle and fat?
GH is anabolic on muscles and catabolic on fat
What hypothalamic hormones regulate GH?
GHRH causes GH release and somatostatin inhibits GH release
What is the effect of GH in childhood?
Linear growth, growth of long bones, cartilage, muscle, and organ systems
What are the effects of GH in adulthood?
Protein synthesis, bone density
Lipolysis
Glucose release, reduced insulin sensitivity
What enzyme mediates most of the effects of GH?
IGF-1
Characteristics of child with GH deficiency
Short stature, adiposity, hypoglycemia (due to hyperinsulinemia)
Characteristics of adult with GH deficiency
Increased adiposity, decreased muscle mass
Decreased bone mass
Cardiac muscle atrophy, atherogenic lipid profile
Overall malaise
What is Sermorelin?
Synthetic GHRH
Used when pituitary has normal function, defect in GHRH/hypothalamus
What are Somatropin and Somatrem?
Synthetic GH
Works as long as IGF-1 function is intact
What is Mecasermin?
Synthetic IGF-1
Used when defect is in GH receptor or there are antibodies against GH
How does the structure of Somatropin and Somatrem differ from GH?
Somatropin is identical to GH
Somatrem has an extra methionine at the N-terminus
What pediatric conditions are treated with recombinant human growth hormone (Somatropin/Somatrem)?
GH deficiency Chronic renal failure Prader-Willi Turner syndrome Idiopathic short stature
What adult conditions are treated with recombinant human growth hormone (Somatropin/Somatrem)?
GH deficiency
AIDS associated wasting
Short bowel syndrome
What side effects are associated with recombinant human growth hormone (Somatropin/Somatrem)?
Neoplasms: Leukemia, melanocytic lesions Hypothyroidism Insulin resistance Arthralgias Induces CYP450 enzymes
What are the contraindications for recombinant human growth hormone (Somatropin/Somatrem)?
Pediatric patients with closed epiphyses
Active underlying intracranial lesion
Active malignancy
Proliferative diabetic retinopathy
What conditions are associated with GH excess?
In children: Gigantism (excessive long bone growth)
In adults: Acromegaly (growth of cartilagenous and deep organs)
What diseases are patients with acromegaly at high risk for?
CV disease
GI disease
GI cancers
Reproductive disorders
What are the treatment options for pituitary adenoma?
Surgical removal
Medical management with somatostatin analogues, GH receptor antagonists or dopamine agonists
What drugs are somatostatin analogues?
Octreotide
Lanreotide
*These drugs inhibit GH secretion from the pituitary