Hormone classes and cellular signaling pathways Flashcards
What are Hormones?
Signaling molecules that relay information throughout the body to regulate biological activities
What are the biological activities regulated by hormones?
- metabolism, growth, reproduction, behavior
- act in distant tissues as well as locally
- produced by specialized cells in large amounts to be able to reach target at effective connections
Paracrine
Cell effects neighboring cells in same tissue
Autocrine
Cell effects itself
Why are hormones produced in large amounts to reach target?
Larger amounts to have enough when reaching target
Where are cell surface receptors located?
Cell Membrane
Classes of Hormones
Peptide/ Protein
Amino Acid Derived
Lipid Derived
Peptides
Oxytocin, Vasopressin (AVP) , GnRH
Proteins
TSH, FSH, LH, Insulin, Glucagon, Prolactin
What do Peptide and Proteins have in common?
Genes
Come form the nucleus
- DNA, RNA, Transcription and Translation
Monoamines
Norepinephrine, Epinephrine, Dopamine
- made from the amino acid tyrosine (specific amino acid)
Steroids
Estradiol , Testosterone, Progesterone, Cortisol, Aldosterone
(all lipid derived)
What do steroids have in common?
Made from cholesterol
Steroids will not have…
will not have genes in DNA because it is made/synthesized by a series of enzymatic reactions, these enzymes are encoded by genes making the hormones
Hormone receptors
Cell membrane receptors (GPCR) and Intracellular receptors (Nuclear receptor)
G Protein-Coupled Receptors (GPCR) overview
- hormone/ligand attaches to 7 transmembrane receptors
- g protein» 3 subunits and is initially attached to GDP
- becomes activated when GTP replaces GDP
- activate g protein activates enzymes
- initiating second messengers
second messenger cAMP
- ACTH activated GS alpha subunit, g protein and enzyme
- activated enzyme ( Adenylyl Cyclase) finds ATP and converts it into cAMP
- cAMP activates PKA and goes into the nucleus
- before going into nucleus it releases PKA finds target proteins and activates by phosphorylating it ( short term effect
- in the nucleus PKA binds with inactive CREB to become activated , phosphorylated CREB that attaches to promoter region and activates transcription and translation (long term effect)
second messengers calcium
- GnRH activates GQ alpha subunit
- g proteins activates PLC
- PLC hydrolyzes PIP2 breaking it apart into DAG and IP3
- IP3 stimulates ER and opens Calcium channels into cytosol
- calcium activates PKC forming phosphorated PKC
- calcium will also bind to CaM»_space; which response to muscle contraction
Calcium will also go into the nucleus and activates transcription of target genes + regulation
Nuclear receptors super family
Steroid receptor family and thyroid receptor family
Steroid receptor family
Corticoid , Androgen, Progesterone, and Estrogen
Thyroid receptor family
Vitamin D, Thyroid, Retinoic Acid
Differences between nuclear receptor superfamily
- Hormones they bind to
- Ability to form homodimer (steroids and thyroid) or heterodimer (thyroid)
- Location in cell
- steroids»_space; cytosol before nucleus
- thyroid»_space; nucleus, already bond to DNA
