Binding overlap and internalization of gonadotropin and thyrotropin in neonatal rat testicle and ovary cell cultures and the Chinese hamster ovary (CHO) cell line

Colloidal-gold-labeled gonadotropin and colloidal-gold-labeled thyrotropin were bound by Chinese hamster ovary (CHO) and primary neonatal rat ovary and testicle cell cultures in the same sites and in the same quantities. The conditions of internalization and the intracellular fate of the bound gold-labeled hormones were also similar in every respect. Pretreatment with either hormone imprinted the cells also for the related hormone, as judged from the increased binding and internalizing capacity of the pretreated cells for either hormone, and from identical patterns of post-binding receptor aggregation.