pituitary hormones and hypothalamic control Flashcards
____ secretes small protein “releasing factors”, except for prolactin
hypothalamus
releasing factors
target anterior pituitary via portal system
anterior pituitary releases which 6 hormones in response to RFs
- somatotrophin (GH)
- Thyrotopin (TSH)
- Follicle stimulating H (FSH)
- Corticotropin (ACTH)
- Prolactin
- Luteinizing hormone (LH)/gonadotropic hormones
posterior pituitary releases —
oxytocin and vasopressin (antidiuretic hormone, ADH)
pituitary gland is known as —
hypophysis
pituitary gland is connect to the hypothalamus by the ____
pituitary/hypophyseal stalk
anterior pituitary contains how many types of secretory cells?
5
somatotropes
- –> growth hormone
- single chain of 191 amino acids
- stimulates body growth; stimulates secretion of IGF-1; stimulates lipolysis
- inhibits actions of insulin on carb and lipid metabolism
thyrotropes
- -> thyroid stimulating hormone (TSH; thyrotropin)
- stimulates production of thyroid hormones by thyroid follicular cells
- maintains size of follicular cells
what are conduced to the anterior pituitary via hypophysial portal vessels?
hypothalamic-releasing and inhibitory hormones
all hormones increase secretions, except the secretion of ____, which is inhibited by ______
all hormones increase secretions, except the secretion of prolactin, which is inhibited by dopamine
______ receives nervous signals from almost all possible sources in NS—collecting center of information for control of secretion by pit gland
hypothalamus
thyrotropin-releasing hormone
causes release of thyroid-stimulating hormone (TSH, thyrotropin) from anterior pit
corticotropin-releasing hormone (CRH)
causes release of adrenocorticotropin from anterior pit
growth hormone-releasing hormone (GHRH)
causes release of growth hormone from anterior pit
growth hormone inhibitory hormone (GHIH)
somatostatin
-inhibits release of GH (somatotropin)
gonadotropin-releasing H (GnRH)
causes release of LH and FSH
prolactin-inhibitory hormone (PIH/dopamine)
causes inhibition of prolactin secretion–elevated dopamine release from HT inhibits prolactin from the anterior pituitary
growth hormone
- somatotropin
- released from anterior pit by GHRH
- small, single chain protein that binds to cell membrane receptors that have “catalytic” property
- affects all/almost all tissues of body
- promotes growth of tissues capable of growing: increased cell size and mitosis – stimulate cartilage and bone growth
- metabolic effects
growth hormone’s effect is manifested through
weight gain
growth hormone’s protein deposition effect in tissues:
- enhancing amino acid transport through membrane
- enhancing mRNA translation for protein synthesis by ribosomes
- increased nuclear transcription of DNA to form mRNA
- decreased catabolism of protein and amino acids
GH increases almost all facets of ______ and ______, while decreasing ______ of proteins
increases amino acid uptake and protein synthesis while decreasing breakdown of proteins
effect of GH on fat utilization
- increases fat utilization for energy
- causes increased release of fatty acids from adipose tissues and their utilization with ketogenic effect
GH decreased cab utilization by
- decreasing glucose uptake/utilizatioon in tissues such as skeletal muscle (increases blood glucose)
- increases glucose production by liver (stimulation of gluconeogenesis, thus increases blood glucose)
- increases insulin secretion (resistance occurs)