estimating % of transcripts originating from each tissue in whole animals

It’s standard to measure gene expression using RNA from whole animals. There are methods to isolate RNA from specific tissues, but if the gene regulatory event you’re studying takes place in a tissue where a large % of transcripts are made, there’s less of an advantage to using tissue-specific isolation.

So my question is: Is there a way to estimate the % of transcripts in whole-animal lysates originating from each tissue? Has an experiment been done that would provide an estimate? Note that I’m not asking how to predict what tissue a given transcript is from.

I can imagine either cell number or cell size/activity might predominate. For example, there are tons of neurons, but the 20 intestinal cells are huge. The germline of course would make a major contribution.

Any insights?