Weird question, i think it'd be something like RER and golgi app since secreted proteins follow this pathway. produced in RER, transported to golgi and then vesicles where it gets secreted through PM.
RER is responsible for protein synthesis and Insuline is a protein. so it would make sense that would be produced by SER. but how does it enter the blood?
Golgi Apparatus because previously synthesized insulin are stored in secretory vesicles.
Remember--Wikipedia is your friend:
The primary function of the Golgi apparatus is to process and package the macromolecules such as proteins and lipids that are synthesized by the cell. It is particularly important in the processing of proteins for secretion.
RER is responsible for protein synthesis and Insuline is a protein. so it would make sense that would be produced by SER. but how does it enter the blood?