Body composition in vivo. IV. Comparisons of the antipyrine and N-acetyl-4-aminoantipyrine spaces in goats

Abstract

The effects of feed and water deprivation on the antipyrine (AP) spaces were studied in five goats. Generally there was no good relationship between loss in body weight, following 24 or 48 hr of feed and water deprivation, and changes in the AP space. The AP spaces were variable and the rates at which AP disappeared from the circulations of our animals also varied. No satisfactory explanation could be given.

Estimates of body water made with N-acetyl-4-aminoantipyrine (NAAP) were always smaller than the simultaneous AP spaces in any animal. Two experiments were made to study these differences in the volumes of distribution of AP and NAAP when both chemicals were injected simultaneously. Both chemicals yielded anomalous spaces in the first experiment when the ruminal contents had been augmented with water, while better results were obtained when the ruminal contents had been augmented with rumen fluid in the second experiment.

Intravenously administered AP appeared in the rumen contents of the goats at greater concentration than NAAP which had been given at the same time, and the differences between the two spaces appeared to be due to this. The rates at which both substances disappeared from the circulation of these animals are given, and the relationship between their disappearance from the blood and appearance in the rumen is discussed.