Effects of Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) 27 and PACAP 38 on the Release of Luteinizing Hormone (LH) from Cultured Bovine Anterior Pituitary Cells.

The effect of pituitary adenylate cyclase-activating polypeptide (PACAP) on the release of luteinizing hormone (LH) from cultured bovine anterior pituitary cells was determined and compared with that of luteinizing hormone-releasing hormone (LHRH). PACAP 27 significantly increased the release of bovine LH at a dose as low as 10-14 M. PACAP 38 also significantly increased the release of LH and the minimal effective dose was 10-12 M. Maximal LH release induced by PACAP 27 (10-7 M) and PACAP 38 (10-7 M) were 40.5% and 71.6%, respectively of control levels. LHRH significantly increased the release of LH at a dose as low as 10-14 M. The increase in LH reached a maximum level which was 3-fold above the basal level at the highest concentration of LHRH tested (10-7 M, P<0.001). LH release induced by PACAP 27, PACAP 38, and LHRH was in a dose-dependent manner. The results suggest that PACAP 27, PACAP 38, and LHRH stimulate the release of LH in the cattle by acting directly at anterior pituitary cells.