Ontogeny of the expression of catecholamine synthesising enzymes in the female porcine median eminence arcuate nucleus complex [MEARC]

The ontogeny of the catecholaminergic system of the median eminence (ME) arcuate nucleus (ARC) complex (MEARC) has been studied in various animal species but so far, nothing has been learnt about the development of catecholaminergic structures in the porcine MEARC. To study this problem the hypothalami from animals at different ages (six groups) were collected. Nerve structures immunoreactive (IR) for the substances studied [(tyrosine hydroxylase (TH), dopamine b-hydroxylase (DbH) and phenylethanoloamine-N-metylthransferase (PNMT)] were found in the pigs at different age periods. In MEARC, TH-IR structures appeared before the 70th day of foetal life, DbH-IR before the 10th week of postnatal life and PNMT-IR only in sexually mature sows.