Introduction to Endocrinology Flashcards
What is neurocrine cell signalling? Examples?
When neural cells release chemical into the blood stream
-> i.e. posterior pituitary: ADH / oxytocin
What type of hormone is TRH?
A small peptide
-> this is in contrast with thyroid hormones themselves, which are amino acid derivatives (tyrosine)
Give an example of positive feedback in endocrinology which relates to ovulation.
The gradual rise in estrogen has a positive feedback on LH, which causes the LH surge.
What does an ultracircadian regulation of secretion mean?
There are minute to minute variations in secretion
vs Circadian when there are day-night variations
How do cortisol levels change during the day?
Lowest at midnight, rapidly peak during early morning hours with a rise in ACTH, and fall progressively thru the day
How do testosterone levels change throughout the day? Is it the same for everyone?
In young men, testosterone levels are lowest during the daytime, and peak during the night time / early morning hours (around 8am) - aka times you would be with your babygirl and are tryna get ur dick wet
In older men = testosterone is fairly constant thru the day
What type of receptors do TGFbeta, activin, and inhibin use?
They all use serine/threonine kinase receptors which traverse the transmembrane domain
What is the “pre” sequence which peptide hormones are synthesized with? What is “Pro”?
Pre - Signal peptide which is required for targeting protein for secretion
-> must be cleaved for activity
Pro - additional non-signal peptide sequence which must be cleaved for hormone activation
Give two reasons why it might be hard to measure hormone levels of ACTH and LH.
- Short half lives -> levels may be different in two samples taken just 10 min apart
- Diurnal / circadian variation is hormone levels
- > timing of sampling is essential
