AJP - Endocrinology and Metabolism, Vol 260, Issue 1 E126-E140, Copyright © 1991 by American Physiological Society
Effects of continuous graded total parenteral nutrition on feeding indexes and metabolic concomitants in rats
M. M. Meguid, T. Y. Chen, Z. J. Yang, A. C. Campos, D. C. Hitch and J. R. Gleason
Department of Surgery, University Hospital, State University of New York Health Science Center, Syracuse.
The influence of graded amounts of total parenteral nutrition (TPN) on food
intake and feeding indexes was investigated in 90 rats housed in Automated
Computerized Rat Eater Meter metabolic cages with free access to water and
chow. When food intake was stable after catheter placement, 10 control rats
continued with the 3 ml/h normal saline used for catheter patency, whereas
study rats were given graded TPN continuously for 3 days, amounting to the
equivalent of 26% (TPN-26), 53% (TPN-53), 81% (TPN-81), or 114% (TPN-114)
of their daily caloric needs. TPN consisted of glucose, fat, and amino
acids in the caloric ratio of 50:30:20. In study rats, the graded TPN
depressed food intake, meal number, meal size, and eventually food
consumption rate, meal sniffs, and intermeal sniffs in a dose- and
time-dependent manner. During graded TPN, rats decreased total food intake
by eating fewer, smaller, shorter meals at a decreasing consumption rate;
sniffing activities were correspondingly curtailed. Stopping TPN led to
normalization of feeding indexes. Blood glucose did not change while plasma
insulin rose with graded TPN. A decrease in hepatic glycogen and an
increase in hepatic triglycerides occurred. Plasma valine, phenylalanine,
and methionine rose in a TPN dose-dependent manner. TPN-26 and TPN-53
significantly decreased whole brain amino acids; with TPN-114 no change
occurred. Brain influx of tryptophan remained unchanged, but a progressive
decrease in brain influx of tyrosine occurred. Whole brain dopamine and
serotonin were depressed with TPN-26 and TPN-81 but were normal with
TPN-114.(ABSTRACT TRUNCATED AT 250 WORDS)
