Lecture 20: Endocrine Principles Flashcards
What is the controlled variable in feedback regulation of hormones?
Degree of activity of the target tissue
What periodic variations in hormone release are superimposed on negative/positive feedback mechanisms?
Seasonal changes, various stages in development and aging
Down regulation of receptors
Number of active receptors may decrease because of increased hormone concentration and increased binding to receptors; decreases target tissue’s responsiveness to hormones
Up regulation of receptors
Number of active receptors/intracellular signaling molecules may increase; increases target tissue’s responsiveness to hormones
What type of receptor is used primarily by neurotransmitters?
Ion-channel-linked receptors
Which receptors have 7 transmembrane segments?
G protein-linked hormone receptors
The leptin receptor (JAK-STAT) transduction pathway is an example of what type of receptor?
Enzyme-linked hormone receptor
Which class of hormones are released via Ca2+ mediated exocytosis?
Polypeptide/Protein hormones (vasopressin, insulin are examples)
Which class of hormones are synthesized from cholesterol and have a common 3 cycolhexyl/1 cyclopentyl backbone?
Steroid hormones (testosterone, cortisol are examples)
Which class of hormones are derived from tyrosin and include thyroid and adrenal medullary hormones?
Amine hormones
Which hormones act directly on DNA?
Steroid hormones, thyroid hormones
Which nuclei are involved in the formation of ADH?
Supraoptic nuclei
Which nuclei are involved in the formation of Oxytocin?
Paraventricular nuclei
What is the function of oxytocin?
Causes contraction of pregnant uterus, aids in milk letdown
What are the functions of growth hormone?
Growth, increased protein synthesis, fatty acid mobilization, decreases glucose utilization, causes liver to form somatomedins
