What are some neuroendocrine structures?
- Neuroendocrine cells of the hypothalamus
- Pineal gland
- Adrenal medulla
NOTE: Oxytocin and vasopressin are neurohormones from the posterior pituatary.
Hypothalamic releasing hormones are synthesized in the hypothalamus an secreted from axonal endings at the ______.
What is the course of hypothalamic releasing hormones?
2. Secreted by axon endings at the median eminence
3. Enter primary plexus of fenestrated capillaries
4. Conveyed from the median eminence to a seconday capillary plexus by the hypophyseal protal vessels
5. Diffuse out of the vasculature and bind to their specific receptors on specific cell types within the anterior pituatary
What is the structure found between the hypothalamus and the anterior pituatary called?
NOTE: The pituatary stock is somewhat fragile and can be disrupted by physical trauma, surgery, or hypothalamic disease
Oxytocin and vasopressin are made by the ________.
REMEMBER: Oxytocin and vasopressin are only stored by the posterior pituatary. The posterior pituatary makes nothing.
If the pituatary stalk is damaged what is one of the first things you will see?
Polyuria and polydypsia (as a result of blocked ADH release)
Functions of the median eminence
What two hormones stimulate the release of prolactin?
PRFs and TRH
____________ is the most important regulator of prolactin.
_______________ inhibits GH.
What is the ACTH receptor found at the target?
MC2R (Gs-linked GPCR)
NOTE: The target endocrine gland are the zona fasciculata and zona reticularis of the adrenal cortex
What is the target of TSH?
What is the receptor for TSH?
TSH receptor (Gs-linked GPCR)
What are the receptors for FSH and LH?
FSH and LH receptors (Gs-linked GPCRs)
What is the GH receptor?
GH receptor (JAK/STAT-LINKED cytokine receptor)
What is the prolatin receptor?
PRL receptor (JAK/STAT-linked cytokine receptor)
What are the most common anterior pituaitary disorders?
Growth Hormone Disorders
What major factors stimulate prolatin secretion?
Pregnancy and nursing
How does somatostatin inhibit GH?
By inhibiting PKA
Stimulators of GH
Increased amino acids
Decreased fatty acids
NOTE: If you suspect that a child has short stature, you can put the child on an exercise device and growth hormone levels should increase. If the levels don't increase with exercise you know something is wrong and you can supplement growth hormone.
Inhibitors of GH
Increased fatty acids
____________ is the transporter for glucose in the muscle and adipose tissue.
NOTE: Growth hormone inhibits glucose uptake inake in muscle and adipose tissue
____________ is the glucose tranporter for glucose in the liver.
GLUT 2 insulin independent)
What affect does GH have on adipose tissue, liver and muscle?
- Decrease glucose uptake
- Increase lipolysis
- Increase in RNA synthesis
- Increase in protein synthesis
- Increase in gluconeogenesis
- Increase in IGFBP
- increase in IGFs
- Decrease in glucose uptake
- Increase in amino acid uptake
- Increase in protein synthesis
IGFs and GH work together to increase the organ size and function of which organs?
GH causes lenthening of bone at the __________.
Side effects of too much GH
Heat issue (like cardiomyopathy
What affect does nutrition have on hormone secretion?
Eating a balanced meal
- Proteins stimulate GH, insulin, and glucagon secretion
- GH inturn produces IGF
Eating a high calorie, high carbohydrate, low protein meal
- Stimulates insulin
- Inhibit GH and IGF
- Increases GH
- Decreases insulin
GH cannot stimulate IGF production in the absence of _________.
Causes of gigantism
- Pituatary GH excess
- Hypothalamic GHRH excess
- Ectopic source of GH or GHRH
NOTE: Gigantism is only seen in growing children