Loading…
Reserve capacities of the small intestine for absorption of energy
Institute of Zoophysiology, University of Hohenheim, D-70593 Stuttgart, Germany Previous in vitro studies showed that the small intestine has reserve capacities for absorption of nutrients. However, the size of the reserve capacity is controversial. Therefore, we measured the intestinal capacity for...
Saved in:
Published in: | American journal of physiology. Regulatory, integrative and comparative physiology integrative and comparative physiology, 1998-07, Vol.275 (1), p.300-R307 |
---|---|
Main Authors: | , |
Format: | Article |
Language: | English |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Summary: | Institute of Zoophysiology, University of Hohenheim, D-70593
Stuttgart, Germany
Previous in
vitro studies showed that the small intestine has reserve capacities
for absorption of nutrients. However, the size of the reserve capacity
is controversial. Therefore, we measured the intestinal capacity for
absorption of energy in relation to the postprandial gastric delivery
of energy into the gut. In minipigs, a 150-cm length of jejunum was
perfused (1-8 kcal/min) with four nutrient solutions containing
60% of energy as carbohydrate, protein, and fat, respectively, or
containing 33.3% of each nutrient. In separate experiments, gastric
delivery of energy to the jejunum was measured after oral
administration of four meals with the same nutrient composition as the
perfusion solutions. With all nutrient solutions, intestinal absorption
of energy demonstrated saturation kinetics. The jejunal capacity for
absorption of energy ranged from 0.66 to 0.94 kcal · m 1 · min 1 .
Despite large differences in nutrient composition of the four meals,
equal amounts of energy (1.3 ± 0.41 kcal/min) were delivered from
the stomach to the jejunum. The absorption rates of energy after meals
ranged from 0.40 to 0.58 kcal · m 1 · min 1 .
Therefore, only 58.8 ± 2.7% of the jejunal capacity for absorption of energy was used. Additionally, the length of small intestine that
would have been required for complete absorption was 42.9 ± 3.7%
of the total length. Results indicate that the feedback control of
gastric emptying provides at least two types of intestinal reserve
capacities: a reserve in absorption (1.7 fold) and a reserve in
intestinal length (2.4 fold).
intestinal absorption; gastric emptying; feedback regulation |
---|---|
ISSN: | 0363-6119 1522-1490 |
DOI: | 10.1152/ajpregu.1998.275.1.r300 |