Endo (pt 2/7) GH and FSH/LH Flashcards
Explain how the hypothalamus plays a role in the release of hormones from the anterior pituitary?
1) Releasing hormones are synthesized by hypothalamic neurons and travel down axons to diffuse into primary plexus of the hypophyseal portal system
2) Releasing hormone is then carried by hypophyseal portal veins to the secondary plexus, and distributed to target cells within ant. Pituitary
3) A specific Hormone is then released from the target cell in the Ant. Pituitary
What is the Hypothalamic Hormone associated with TSH?
Thyrotropin Releasing Hormone (TRH) +
-Regulated by feedback inhibition by the levels of the hormones whose production they control
What is the Hypothalamic Hormone associated with ACTH?
Corticotropin Releasing Hormone (CRH) +
-Regulated by feedback inhibition by the levels of the hormones whose production they control
What is the Hypothalamic Hormone associated with FSH and LH?
Gonadotropin Releasing Hormone (GnRH) +
-Regulated by feedback inhibition by the levels of the hormones whose production they control
What Hypothalamic Hormones are associated with Growth Hormone regulation?
Growth Hormone Releasing Hormone (GHRH) stimulates GH production
Somatostatin inhibits GH production
What Hypothalamic Hormone stimulates Prolactin secretion?
None; trick question. The Hypothalamus does not produce a hormone that specifically stimulates Prolactin secretion.
What Hypothalamic Hormone inhibits Prolactin secretion?
Dopamine -
____ can stimulate Prolactin release when ____ concentrations are high, such as in the setting of primary Hypothyroidism.
TRH; TRH
Which anterior pituitary hormone closely resembles Prolactin?
Growth Hormone (Somatotropin)
-Required during childhood and adolescence for the attainment of normal adult size
-Important effects on Lipid, Protein, and Carb metabolism; lean body mass, & bone density
Growth Hormone
Recombinant form of GH.
-Administered SQ 6-7 x’s per week (absorption = 70-90%)
-1/2 life = 1.75 hours
-Duration = 36 hours
Somatropin (rhGH)
Growth promoting effects of GH are mediated principally through an increased production of?
Insulin-Like Growth Factor 1 (IGF-1)
Produced in the Liver.
-Essential for normal prenatal and postnatal growth
-Becomes dependent on GH during the 1st year of life
IGF-1
Stimulates:
-IGF-1 production in bone, cartilage, muscle, kidney & other tissues
-Longitudinal bone growth
-Anabolic effects in muscle
-Catabolic effects in lipid cells
Growth Hormone
T/F: You can safely ingest native GH?
False; ingestion of native GH causes prion disease.
-Rapidly progressive and fatal
-Creutzfeldt-Jakob Dz
-Variant Creutzfeldt-Jakob Dz (Human version of mad-cow dz)
What are 2 examples of Syndromes caused by GH deficiency?
1) Turner Syndrome
2) Prader Willi Syndrome
X-Linked recessive GH deficiency.
-Short stature, low hairline
-Shield-shaped thorax, widely spaced nipples
-Constriction of aorta
-No menstruation, rudimentary ovaries, Poor breast development
Turner Syndrome
Autosomal Dominant (M or F) obesity in childhood.
Prader Willi Syndrome
How do you treat genetic syndromes caused by GH deficiency?
Recombinant Somatotropin
What are acquired causes of GH deficiency?
Pituitary/Hypothalamus damage (intracranial tumors, infections, infiltrative or hemorrhagic processes, or irradiation)
Has 191 Amino Acid Sequence identical to native GH.
-Increases activity of the CYP450 (CYP450 Inducer)
Somatropin
Somatropin may ____ the serum levels of drugs metabolized by CYP450.
Reduce
What are clinical uses for Somatropin?
-Growth Failure in pediatric patients associated with GH deficiency, chronic renal insufficiency post-transplant, Noonan Syndrome, Prader-Willi, Turner syndrome, idiopathic short stature
-GH deficiency in adults
-Wasting in patients with HIV
-Short bowel syndrome in patients receiving specialized nutritional support
-Used by athletes to increase muscle mass and improve performance (banned)
-Used in 1993 in rbGH (recombinant bovine) to increase milk production in dairy cattle. Mastitis = inc abx residue in milk.