2/12-15: Pituitary Hormones Flashcards
What is a true endocrine gland?
Anterior pituitary gland
What gland contains axon terminals of hypothalamic neurons?
Posterior pituitary gland
What hormones does the pituitary gland secrete?
Peptide hormones
What hormones are in the anterior pituitary?
- Growth Hormone
- Adrenocotricotropin (ACTH)
- Thyroid-Stimulating
Hormone (TSH) - Follicle-Stimulating
Hormone (FSH) - Luteinizing Hormone (LH)
- Prolactin
What hormones are in the posterior pituitary?
- Antidiuretic Hormone
(ADH)/Vasopressin - Oxytocin
What do somatotrophs secrete?
GH
What do corticotrophs secrete?
ACTH
What do thyrotrophs secrete?
TSH
What do gonadotrophs secrete?
LH and FSH
What do mammotrophs secrete?
Prolactin
What do adenomas involving somatotropic cells cause?
gigantism if occurring in
children before closure
of the long bones’
epiphyseal plates or
acromegaly in adults,
with musculoskeletal,
neurologic, and other
medical consequences
What do neurons in the hypothalamus do?
Synthesize and secrete hypothalamic releasing and inhibiting hormones that control the endocrine cells in the anterior pituitary
Where are hypothalamic hormones released into?
Primary capillary plexus in the median eminence
What do hypothalamic-hypophyseal portal blood vessels carry?
The hypothalamic hormones to the sinuses of the anterior pituitary gland
What hormones stimulate release?
TRH (thyrotropin releasing hormone)
GnRH (gonadotropin releasing hormone)
CRH (corticotropin releasing hormone)
GHRH (growth hormone releasing hormone)
PRH (prolactin releasing hormone)
What hormones inhibit release?
GHIH (somatostatin)
PIH (prolactin inhibiting hormone - dopamine)
What do hypothalamic regulatory hormones bind to?
G-protein coupled receptors in various endocrine cells of the anterior pituitary
How do hypothalamic regulatory hormone stimulate or inhibit AP hormone secretions?
Through generation of second messenger
What kind of hormone is GH?
Peptide hormone
What does GH release?
Insulin-like growth factor-1 (IGF-1)
What does GH act on?
Target tissues and as a tropic hormone to the liver
What is pulsatile secretion?
Lower concentrations during the day with highest levels a few hours after sleep
What is growth hormone secretion stimulated by?
starvation
(protein deficiency), fasting
(hypoglycemia), stress,
exercise, and excitement
When is secretion of the growth hormone?
neonatal period but decreases in childhood. Peak levels during puberty and then they decline with age
What are growth and metabolic effects of GH produced by?
IGFs (also called somatomedins)
Where is IGF-1 produced?
Most tissues
What does IGF-1 act on?
Neighboring cells in a paracrine manner