Enteroendocrine cells of the intestine are the most numerous endocrine cells of the body. In a sense they are known to act as chemoreceptors, initiating digestive actions and detecting harmful substances and initiating protective responses.
The typical manufacturer's warranty on a solar panel is 25 to 30 years, but panels can last up to 40 years with care and attention.
Somehow the myth got started that it takes more energy to make a solar panel than the panel generates in its lifetime. But that's simply not true. The energy payback time on a panel is typically less than two years (CleanTechnica, WP), and most panels will produce useful electricity for 25 years or more.