Observations on pituitary and cerebral catecholamines in Brattleboro rats

The combined neural and intermediate lobes (N.I.L.) of the pituitary glands of Brattleboro rats contained significantly more noradrenaline (NA) than those of normal controls of the same age. In addition, in 4 and 6 months old rats the N.I.L. of the homozygotes (Di-rats) contained about twice as much NA as those of the heterozygotes (non-Di-rats). In the enlarged and hyperaemic neural lobes of the Di-rats enlarged blood vessels could be seen. They were surrounded by a rich network of nerve fibres which displayed catecholamine fluorescence. The NA concentrations in the medial basal hypothalamus (M.B.H.) of 4, 6, and 9 months old Di-rats were significantly higher than those of the non-Di-rats and of controls of the same age. This may contribute to the diminished ACTH secretion in Brattleboro rats. The total amount of DA contained in the N.I.L. of 9 months old Di-rats was 20% lower than in the non-Di-rats of the same age. The concentrations of homovanillic acid (HVA) in the corpora striata of 4 months old Di- and non-Di-rats was significantly higher than in older Brattleboro rats and in control rats of various strains and ages. At 9 months it was nearly twice as high in the Di-rats as in the non-Di-rats. The concentrations of dihydroxyphenylacetic acid in the striata of 4--6 months old Di- and non-Di-rats were higher than those of Long Evans rats of the same age.