CHANGES OF HISTAMINE CONCENTRATION IN CHICKEN OVIDUCT DURING THE EGG-LAYING CYCLE

This study was undertaken to determine histamine concentration in chic ken oviductal parts (infundibulum, magnum, isthmus and shell gland) in relation to the egg location within the oviduct and ovulation. The ex periment was performed on Hisex Brown laying hens with regular sequenc es of at least four eggs. Ovulation occurred within 5-15 min of ovipos ition oi the previous egg In the series. Histamine was determined spec trofluorometrically in the following stages of the egg-laying cycle: d uring c(2) oviposition; 0.5 h, 6.5 h, 12.5 h and 18.5 h after c(2) ovi position; and during c(3) oviposition. Irrespective of the egg formati on stage histamine concentration in the examined oviductal parts was a rranged in the following order: infundibulum > magnum > isthmus > shel l gland. During the egg-laying cycle histamine concentration significa ntly changed. During oviposition, i.e. just before ovulation of the ne xt egg in the series, histamine concentration significantly increased in the infundibulum while 6.5 h after oviposition, i.e. about 1.5 h of the egg stay in the shell gland, there was a significant increase in histamine concentration both in th infundibulum and the shell gland. I n the magnum histamine concentration was elevated when the ovum entere d the segment, i.e. 0.5 h after oviposition. There were no changes in histamine concentration in the isthmus. It is suggested that histamine participates in the local events taking place in the hen oviduct duri ng the egg formation cycle.