Biochemistry - Peptide Hormones
Terms
undefined, object
copy deck
- Hormone substances that act at a distance
- Endocrine factors
- Hormone substances that act close to the cells that sectrete them
- Paracrine Factors
- Hormone substances that act directly on the cells that secreted them
- Autocrine Factors
- Chemical messengers that mediate intercellular communication
-
Cytokines
Growth Factors
Hormones - Carrier proteins for peptide hormones prevent
- hormone destruction by plasma proteases
- Carriers for small hydrophilic AA hormones prevent
- filtration through renal glomerulus
- Receptors for most AA, peptide hormones are located
- on the plasma membrane
- Activation of receptors by AA hormones (1st messengers) leads to INTRACELLULAR production of
- 2nd messengers
- The main 2nd messengers
-
cAMP
Ca2+
IP3
DAG - Proteins are Phosporylated on Ser and Thr by
-
PKA (cAMP dependent)
PKC (DAG activated) - There are receptor Ser or Thr
- Kinases
- The blood vessel that carries hypothalamic-releasing hormones to the pituitary is called the
- portal vein
- One capillary bed is in the hypothalamus and the other is in the
- Anterior Pituitary
-
Hypothalamus - pituitary
+ Releasing Hormones -
GHR - Growth Hormone Rel. H
TRH
GnRH
CRH
PRF - The principal source of IGF-1
- Liver (other tissues secrete and contribute)
- IGF-1 regulation at the hypothalamus stimulates secreteion of___ which inhibits secretion of ______ at the pituitary
-
Somatostatin
Growth Hormone - Direct IGF-1 action on the pituitary leads to down-reg of
- Growth Hormone
- Anterior Pituitary Hormones that directly affect the body
-
Growth Hormone
Prolactin
MSH - Anterior Pituitary homrones that regulate other glands
-
TSH
ACTH
FSH
LH - Stimulates the development of mammary glands and production of milk
- Prolactin
- Stimulates melanocytes to sythsize melanin
- MSH
- Hormone that acts thyroid - thyroxin
- TSH
- Hormone that acts adrenal cortex - cortisol
- ACTH
- Hormones that act ovaries and testes - sex hormones and gamete production
-
FSH
LH - Promotes gluconeogenesis and is hyperglycemic. Promotes AA uptake in cells.
- Growth Hormone
- Lack of ability to secrete GH - respond well toi GH therapy
- GH-def. dwarfs
- Lacj IGF-1 response to GH but not metabolic effects - def. in post-receptor manner
- Pygmies
- Production of excessive GH before ipiphyseal closure of long bones
- Gigantism
- GH excessive after epiphyseal closre
- Acromegaly
- Posterior Pituitary Hormones
-
Oxytocin
ADH - Anterior Pituitary - TSH - Thyroid gland - (metabolic rate)
- Thyroxin
- Anterior pitutary - ACTH - Adrenal Cortex - (raises glucose levels in the blood)
- Cortisol
- Anterior pituitary - FSH, LH - Gonads -
-
FSH - gamete production
LH - sex hormone production
testosterone, estrogen, progesterone -
Protein receptors -
Highly ______ for hormone - Specific
-
Protein receptors -
High affinity for - Binding (high Ka, low Kd)
-
Protein receptors -
Low numbers per cell - Saturable
-
Protein receptors -
__________ in responding tissues - Localized
-
Protein receptors -
Binding to hormones is _____ and ________ - noncovalent and reversible
- Three Major Groups of peptide membrane Receptors
-
Linked to ion channels
Serpentine linked to G proteins
Growth Factor, cytokines - 1 tansmembrane domain - NZ linked - The signaling cascades of membrane-bound receptors invole PROTEIN PHOSPHORYLATION by
- Kinases
-
G Proteins -
Binding of H induces - Conformational change in receptor
-
G Proteins -
Activated Receptor Binds to - Ga Subunit
-
G Proteins -
G Proteins -
Binding Induces conf. change to Ga, GDP dissociates and is replaced by _______, Ga dissociates - GTP
-
G Proteins -
H dissociates from receptor: Ga binds to effector ______ - Activating it
-
G Proteins -
________ of GTP to GDP; Ga dossociates - Hydrolysis
- B-adrenergic receptors bind ______
- Epinepherine and adrenaline
- B-adrenergic receptors are found in
-
Mucsle
Liver
Fat Cells - B-adrenergic receptors are activated when
- energey reserves in these tissues are mobilzed
- B-adrenergic receptors have 7 membrane spanning
- alpha helices - serpentine
- B-adrenergic receptors - as long at GTP remains bound to Ga subunit - it will continually
- Activate adenylate cyclase
- Some bacterial toxins work to inactivate (Cholera)
- GTPase activity - keeping it active - too much cAMP
- Ras binds to GDP/GTP and has
- GTPase activity
- RAS - Ser/Thr Kinase Cascade - activates ________
- MAP Kinase - Transcription Factor
- The Pancreas secretes NZ into the Duodenum through the
- Pancreatic duct (Exocrine Gland)
- Group of cells in Pancreas that secrete Insulin and Glucagon
- Islets of Langerhans
- Islets are endocrine because they are
- Ductless
- Insulin has a ____ receptor and is produced by the
-
tyrosine kinase receptor
B-cells - Insulin Promotes
- Removal of glucose from the blood for stoage as glycogen
- Insulin inhibits ______ use as an energy source
- buildup of fats and proteins
- Glucagon is produced by the
- a-cells
- Glucagon is secreted When?
- between meals to maintain glucose concentration
- Glucagon raises
- level of glucose in the blood