Hello Ece İdil

I suggest a Western Blot for your experiment. Western Blot is a powerful technique to detect a single or a complex of proteins and to monitor changes in expression levels. You need to see whether the estrogen receptors are upregulated in the brain following manipulation. So, Western Blot would be the most appropriate technique.

On the other hand, immunohistochemistry will allow you to detect the exact location of a target protein within a tissue sample. It could be a robust method for investigating protein expression in target brain locations. It could give you all the necessary qualitative information that you have asked for in your question. However, immunohistochemistry is subject to variability in sensitivity, specificity and reproducibility, and is generally, at best, considered semi-quantitative. The scoring systems most commonly used, either ordinal or nominal, generate discontinuous, highly subjective data. Nevertheless, I am attaching an article below for your reference wherein the investigators have used Q-IHC to determine receptor quantity in archived tissues.

Article Quantitative Immunohistochemistry by Measuring Cumulative Si...

For semi-quantitative or quantitative analysis Western Blot is appropriate. The most prominent advantage is that it has proven to be effective at generating a signal that is proportional to the amount of the protein that exists in the sample. Also, Western Blot is often chosen for its ability to detect numerous target proteins simultaneously, having the effect of significantly cutting down on testing time as well as reducing the number of resources required.

If you have the required resources and time, then I feel you should perform both the techniques, immunohistochemistry as well as Western Blot.

Best.