Lec 9 - Measuring hormones Flashcards
4 reasons we need yo measure hormone levels
- establish normal ranges
- clinical diagnosis
- assess effectiveness of treatment
- understanding endocrine physiology
2 assay methods
immunoassay = measure molecular structure or mass
Bioassay = measure biological activity (e.g. Patch clamp electrophysiology)
2 types of measuring mass of hormone
immunoassay - competitive
Immunometric assay - non competetive
What is immunoassay
Competitive binding assay between labelled known hormone and unlabelled unknown hormone for a limiting amount of antibody
What is usually used to tag hormone in radioimmunoassay
iodine 125
What is used to remove the free labelled antibody
charcoal
Relationship between hormone and signal in immunoassay curve
Indirectly proportional
What is immunometric assay
2 diff monoclonal antibodies which bind to 2 epitopes of a single hormoe used, where the 2nd will be labelled in some way = non competitive
Elisa
enzyme linked immunosorbent assay
Diff between Elisa and imunometric assay
the 2nd antibody is a labelled enzyme e,g, horseradisb peroxidase
Then the colour change is measured
2 types of elisa
competitive and non competitive
Pros of the immunoassays
- highly sensitive
- highly specific
- highly precise
- very convenient
In vivo vs in virtro bioassays
in vivo is with a live animal
In vitro is cell culture
What does bioassay determine
the magnitude or intensity of biological effect
How can bioassay be used to see potency of recombinant hormones
E.g. Used for insulin drug testing
Can determine correct dose
