Where does “neuroendocrino” come from?

neuroendocrino (Spanish) comes from Spanish endocrino, from Latin endocrinus, from Spanish endo-, from Ancient Greek ἔνδον, from Proto-Hellenic éndon, from Proto-Indo-European h₁n̥dóm, from Proto-Indo-European h₁n̥dó, from Proto-Indo-European h₁én — in.

neuroendocrino (Spanish): neuroendocrine