Dear SirI am a student. I have sheep liver and kidney samples....

Hi, we have never used this protocol to analyze samples other than mouse livers. I assume that it would work as well. Glycogen is also present in the kidney in a small amount --- I didn't find out how much it is. You may check this reference as well:

Bulletin of Environmental Contamination and Toxicology
JAN.–APRIL 1979, Volume 21, Issue 1, pp 269-272
Levels of blood glucose and tissue glycogen in two live fish exposed to industrial effluent

A. D. Diwan, H. G. Hingorani, N. Chandrasekhram Naidu

They analyzed fishes, and the relative glycogen abundance in different tissues could provide you with a reference.

BTW, please also be aware that liver glycogen level increases significantly after meals.

Hope this info could be of help to you.

Best,
Peichuan