Hypothalamus and Pituitary Flashcards
Where is vasopressin synthesized, secreted, and what’s its function?
Synthesized in hypothalamus, secreted in posterior pituitary and inhibits water diuresis.
Where is oxytocin synthesized, secreted, and what’s its function?
Synthesized in the hypothalamus, secreted in the posterior pituitary and stimulates uterine contractions and lactation.
Where is growth hormone synthesized, secreted, and what’s its function?
Synthesized/secreted in the anterior pituitary and affects metabolic processes in the body. Deals with growth.
Where is prolactin synthesized, secreted, and what’s its function?
Synthesized/secreted in the anterior pituitary and stimulates lactation in primed mammary tissues.
Briefly compare the structures of vasopressin and oxytocin.
Both are nonapeptides with intramolecular disulfide bonds. Primary structure differs by 2 amino acids
What is the situation with respect to growth hormone and its receptors in Laron dwarfs, G.H. deficient dwarfs, pygmies, acromegaly and gigantism?
1) Laron dwarfs have excessive G.H. but lack hepatic receptors = low levels of lGF
2) G.H. deficient dwarfs have normal receptors but low G.H.
3) Pygmies have normal G.H. levels. low levels of IGF and a G.H. receptor defect.
4) Acromegaly = excess G.H. after epiphyseal closure. Normal receptor.
5) Gigantism = excess G.H. before epiphyseal closure. Normal receptor.
Name 3 glycoprotein hormones synthesized and secreted at the anterior pituitary and give their functions.
1) TSH - increases volume and vascularity of thyroid gland and Iodine concentrations.
2) FSH - stimulates growth/development of ovarian follicle and spermatogenesis.
3) LH - maturation of ovarian follicle and androgen production by Leydig cells.
What is the POMC family of hormones? Give 3 members, their function, where they are synthesized and secreted.
Pro-opiomelanocortin hormones act as hormones, neuromodulators and neurotransmitters. They are synthesized in the gut/reproductive tract and secreted from the anterior pituitary.
1) ACTH - regulates growth and function of adrenal cortex.
2) Beta-LPH - causes lipolysis and fatty acid mobilization
3) MSH (melanocyte stimulating hormone) - dispersion of intracellular melanin granules
What is Cushings syndrome?
Excessive production of ACTH by pituitary gland or a tumor. Symptoms: hyperpigmentation, Na+ retention, glucose intolerance, muscle atrophy, etc. Typically no metastatic potential.
Give 4 releasing hormones and 2 inhibitory factors secreted by the hypothalamus and list their functions.
1) TRH (thyrotropin releasing hormone) - stimulates release of thyrotropin and prolactin.
2) GnRH (gonadotropin R.H.) - stimulates release of LH and FSH.
3) CRH (corticotropin R.H.) - stimulates release of ACTH and Beta endorphin.
4) GHRH (growth hormone R.H.) - stimulates release of GH.
5) GHR inhibitory factor - (somatostatin) inhibits G.H., insulin, glucagons and gastrin release.
6) PRL inhibitor - inhibits prolactin release from high dopamine concentrations.
