Introduction to Endocrine Flashcards
(24 cards)
What are paracrine chemicals?
Act local to the sit of synthesis e.g. histamine
What are autocrine chemicals?
Act on the same cell they are synthesized in
What are exocrine chemicals?
Released from an exocrine gland via ducts to the external environment
What is a peptide hormone composed of?
Amino acid chains
What is the name of the initial peptide hormone produced by the ribosomes?
Preprohormone
What is the inactive fragment of insulin called?
C-peptide
How many times higher are C-peptide levels in the blood/urine than insulin?
x5 (insulin metabolized faster)
How do most peptide hormones create a response when they bind to a receptor?
Modulate the GPCR or tyrosine kinase linked signalling pathways
What are peptide hormones properties in relation to water/ lipids?
Hydrophillic/lipophobic
Which will elicit a faster response if activated: GPCR or Tyrosine kinase linked receptor?
GPCR
What are the stages of peptide hormone synthesis and storage?
Amino acids - preprohormone - prohormone (packaged into vesicle) - hormones
What are all steroid hormones derived from?
Cholesterol
How are steroid hormones carried in the blood and why?
By carrier proteins due to being hydrophobic
Why is the half life of steroid hormones longer than peptide hormones?
They are protected from enzymatic degradation by carrier proteins in the blood
Where in the body are steroid hormones produced?
Gonads (androgens)
Placenta
Kidney (vitamin D3)
Adrenal cortex (corticosteroids)
Where are the receptors for steroid hormones?
Inside the cell (cytoplasmic or nuclear)
What is the general effect of a steroid hormone in the cell?
Activate or repress gene
What amino acid are most amine hormones derived from?
Tyrosine
What is the only amine hormone derived from trytophan?
Melatonin
How do we calculate total plasma hormone concentration?
Free hormone + complexed hormone
What can be downregulated to influence target cells response to hormones?
Hormone receptors
What effect will prolonged exposure to low hormone plasma have on cell receptors?
Leads to up-regulation of hormone receptors
What is a permissive effect?
When one hormone enhances the effect of another
What effect does thyroid hormone have on epinephrine?
Increases lipolytic effect of epinephrine (TH increases number of epinephrine receptors on adipocytes)
