My understanding is that most of the metabolic activity required in the lens takes place in the germinative zone you mentioned and then proteins necessary for l

My understanding is that most of the metabolic activity required in the lens takes place in the germinative zone you mentioned and then proteins necessary for lens health diffuse through abundant gap junctions from the lens cortex into the lens core. Take all of that with a grain of salt though. I haven't studied this in depth but I did work in a lab that studied gap junctions of the lens in undergrad Also, here is an NCBI article all about the lens: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5538311/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5538311/