Lab 4: Endocrinology Flashcards
What is endocrinology?
Study of the hormonal controls of the bodily function.
What is a hormone?
A chemical substance synthesized and secreted by an endocrine gland, which is transported by the circulatory system to inhibit, stimulate, or regulate the functional activity of the target organ or tissue.
What is progesterone (P4) and where is it produced?
A steroid hormone produced by corpus luteum (CL).
What is the corpus luteum?
Transient endocrine organ that forms on surface of ovary following ovulation. If pregnancy does not occur, CL will regress and amount of progesterone circulating body will decrease in time for new cycle to begin.
Function of progesterone?
Prepares reproductive tract and mammary glands for pregnancy, prevents contraction of uterus to not expel fetus.
What can progesterone levels be used for?
To monitor ovarian activity, early embryonic mortality, ovarian disorders, detect estrus (heat) - to know when to artificially inseminate, diagnose pregancy (levels drop when not pregnant).
Is progesterone considered a hormone of pregnancy?
No.
How can progesterone levels be measured?
Radioimmunoassay (RIA) or Enzyme-linked immunosorbent assay (ELISA).
What do the immunoassays rely on?
The interaction between specific monoclonal antibodies (mAbs) and the substance of interest.
Difference between RIA and ELISA?
RIA - quantitation using radioactivity.
ELISA - quantitation using enzymatic rxns.
Pros and cons of RIA?
Pros - highly specific and sensitive
Cons - radioactivity is hazardous, radioactive labels decay over time, more expensive
Pros and cons of ELISA?
Pros - Safer, results have longer shelf lives, lack of disposal problems, cheaper
Cons - Not as specific or sensitive.
What are reasons that progesterone levels are low?
Not pregnant, disease, etc. (therefore, can’t be sure low levels just b/c not pregnant.)
What does it mean for farmers if progesterone levels are high?
Know NOT to artificially inseminate.
Can you be sure that a cow is pregnant due to high progesterone levels?
No, b/c it may be due to disease, etc. ELISA only rules out negative results (eg Cow is not pregnant when levels are high).
Review how to determine concentration of a sample.
GO NOW!
Need to know blood collection of animals?
Maybe you should review them on Thursday… Scroll down on Lab 4 notes.
What is radioimmunoassay (RIA)?
Separation of protein (from mixture) using specificity of antibody - antigen body. Quantitation using radioactivity.
What is ELISA?
Enzyme-linked immunosorbent assay, molecule detected by antibodies that have been made against it. Quantitation by same antibodies coupled to an enzyme (eg enzyme that produces a coloured product from a colourless substrate).
What is an antigen?
A foreign molecule that causes an immune response. Eg. polysaccharides, large protein hormones.
What are antibodies and what are they produced by?
A protein produced by B-lymphocytes.
What are the standards?
The antigen of known concentrations.
