The effects of PACAP and VIP on the in vitro melatonin secretion from the embryonic chicken pineal gland.
The effects of in vitro VIP administration and those of in ovo pretreatment with PACAP antagonist (PACAP6-38) on the development of the embryonic melatonin (MT) secretion were investigated. With dynamic in vitro bioassay we showed that (1) the development of the circadian MT secretion seems to be unaffected by VIP administrations or by PACAP6-38 pretreatments; (2) exposure of the embryonic chicken pineal gland to VIP induces transitory increase in MT secretion at or before the 14th embryonic day in vitro.