Epidermal tissue as this is what makes up the lining  
 
        
             
        
        
        
I think it would be in the cells
        
             
        
        
        
Answer:
There is a chance that the person receiving that insulin will get a bad immune response, and there is a possibility that the animal might have a disease or infectious organisms, that their insulin might contain, and putting it inside a human might transmit that disease.
Explanation: