An assay for growth hormone and prolactin-releasing activities using a bovine pituitary cell culture system.

Bovine anterior pituitary cells were enzymatically dispersed and cultured for 3 to6 days in small petri dishes. The release of GH, PRL, or TSH into the media during a 4-hr incubation period was used as an index of releasing activity. Addition of I or more ng per ml of TRFincreased release of PRL and TSH and addition of over 10 ng⁄ml increased release of GH. Porcine hypothalamic fragments (SME) were extracted with 90% methanol and subjected togel filtration on Sephadex G-25. GH-releasing activity (GHRA) was eluted in fractions with elution volumes similar to TRF. When TRF in these fractions was destroyed by incubation with human serum, GHRA was maintained. Thus TRF did not account for the GHRA observed. A dose response wasobserved utilizing extracts containing the equivalent of 0.0025 to 0.25 SME. Lysine vasopressin,the “GHRA” peptide described by Schally et al. (1), LRF and several TRF analogs were inactive in this system. Purified HE (hypothalamic extract) also stimulated release of RL.Destruction of TRF...