Effect of age of donor on the responsiveness of dispersed and cultured chicken anterior pituitary cells to GnRH-I.

1. The aim of this study was to devise a method to prepare and culture anterior pituitary cells from juvenile and adult chickens in order to investigate mechanisms controlling gonadotrophin-releasing hormone-I (GnRH-I)-induced luteinising hormone (LH) release in vitro. 2. The optimum culture medium for maintaining gonadotroph responsiveness to GnRH-I was bicarbonate-buffered and phenol red-free Medium 199 supplemented with 10% foetal calf serum. 3. Cultured pituitary cells from juvenile chickens were more responsive to GnRH-I than cells from adult cockerels, while no LH was released in response to GnRH-I from pituitary cells from laying hens. 4. Cultured pituitary cells from adult chickens of both sexes released LH in response to 12-O-tetradecanoyl-13-phorbol acetate (TPA), an activator of an enzyme involved in intracellular signalling, protein kinase C. 5. It is concluded that freshly-dispersed and cultured gonadotrophs from adult chickens do not regain their responsiveness to GnRH-I as well as freshly-dispersed and cultured gonadotrophs from juvenile chickens. It appears that the stimulus-secretion coupling pathway between the GnRH-receptor and the activation of protein kinase C in gonadotrophs from adult chickens is more easily disrupted by dispersion and culture than in gonadotrophs from juvenile chickens.