Bovine lactotroph cultures for the study of prolactin synthesis functions.

The aim of this study was to establish a bovine anterior pituitary-derived lactotroph (BAPDL) line that expresses prolactin (PRL) in vitro to study the mechanisms of bovine PRL synthesis and secretion. Immunohistochemistry assay of PRL in the newborn calves' anterior pituitary glands showed that most lactotrophs were located within the superior border of the lateral wings of the anterior pituitary. Tissues of the superior border of the lateral wings of the anterior pituitary were dispersed and cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% fetal bovine serum (FBS). The limiting dilution method was used to establish BAPDL from single cell clone. BAPDL cells constantly expressed mRNAs for PRL and pituitary-specific transcription factor 1 (Pit-1) gene and grew steadily and rapidly in the DMEM supplemented with 10% FBS. PRL immunoreactivity was present in BAPDL at passage 20. The concentration of bovine PRL in BAPDL at passage 20 culture supernatant was decreased to below 35% compared with that in BAPDL at passage 1. The effects of human epidermal growth factor (hEGF) and dopamine (DA) on the expression and secretion of PRL in BAPDL at passage 4 were also investigated. The results are consistent with those of previous studies. Thus, it can be used successfully for studying the mechanisms of stimuli regulating PRL synthesis and release.