Concanavalin-A-bound and -unbound prolactin in normal and hyperprolactinaemic rats

Concanavalin-A (Con-A)-bound and -unbound forms of prolactin were studied in female Wistar-Furth rats, both normal and with hyperprolactinaemia induced by treatment with oestrogen or a prolactinoma graft. In normal rats, Con-A-bound prolactin was the major circulating form (more than 50%) and a minor pituitary component (less than 10%), essentially as 25 kDa prolactin. In oestrogen-treated rats, plasma prolactin levels were 100-fold higher and pituitary weight was fivefold higher than in the controls, but total pituitary prolactin content was unmodified