Actin serves as one of the major cytoskeleton structures. It is a crucial component involved in a plethora of processes in cell biology:  stabilizing the cell shape, cell movements (e.g. cell migration)  and intracellular movements and transport mechanisms.

Actin is a 43 kDa protein that is very highly conserved between species. Actin has three main isotypes (α-actin, β-actin and γ-actin), which show >90% amino-acid (aa) homology between isotypes and >98% homology within members of a particular isotypic group.

Corticosterone is a glucocorticoid secreted by the cortex of the adrenal gland in response to stimulation by adrenocorticotropic hormone. Corticosterone is a major indicator of stress in non-human mammals. Glucocorticoids, such as corticosterone, guide fundamental processes associated with converting sugar, fat, and protein stores to useable energy; inhibiting swelling and inflammation, and suppressing immune responses following a stress event.

Measuring Corticosterone

Comparison of the EIA kit described in this post with traditional RIA, using 1 ul mouse tail bleed samples.

Competitive immunoassays, such as RIA and EIA methods, are the typical means for measuring levels of corticosterone in biological matrices. Most RIAs or EIAs require solvent extraction techniques to measure serum or plasma corticosterone levels, however extraction may be very difficult or impossible with mouse samples due to the large volumes of plasma or serum required for most extraction protocols.