Effect of total parenteral nutrition on histamine in the rat brain and other tissues.

The effects of a constant infusion of total parenteral nutrition on the histamine content of the hypothalamus was studied in adult male rats. Histamine content of the stomach, kidney, liver, and heart was also determined. The relationship between tissue histamine levels and duration of the infusion was examined. Rats receiving intravenous infusions of total parenteral nutrition had significantly higher (p less than 0.001) histamine levels in the hypothalamus than did orally-fed control rats. No difference was observed in the histamine level in the remainder of the brain. Animals receiving parenterally infused nutrient solutions had a higher histamine content in the kidneys but lower histamine levels in the stomach than did the control rats. No changes in the histamine content of liver or heart were observed. It appears that increases in histamine levels in the kidney and hypothalamus of rats given total parenteral nutrition persist up to 5 days and 9 days, respectively. The mechanisms responsible for and the consequences of the alterations of histamine content of these tissues remain to be established.