Related Experiment Videos
Hypertonic glucose preloads act preabsorptively to decrease intake in rats on postnatal day 18
A Weller1, L Tsitolovskya, G P Smith
1Developmental Psychobiology Laboratory, Department of Psychology, Bar Ilan University, Ramat Gan 52900, Israel.
Insights
Preloads of glucose, not injections, significantly inhibit intake in young rats. This suggests a preabsorptive osmotic mechanism, not postabsorptive metabolism, controls early feeding behavior.
Area of Science:
- Physiology
- Neuroscience
- Behavioral Science
Background:
- Understanding factors that regulate feeding behavior is crucial for addressing appetite and metabolic disorders.
- Early life feeding experiences can have long-lasting effects on metabolic health.
Purpose of the Study:
- To investigate whether glucose preloads inhibit food intake via preabsorptive or postabsorptive mechanisms in developing rats.
- To differentiate between osmotic and metabolic roles in glucose-induced satiety.
Main Methods:
- 18-day-old rat pups underwent 24-hour food deprivation followed by a 30-minute feeding test.
- Gastric preloads or intraperitoneal injections of glucose or 2-deoxy-D-glucose (2-DG) solutions were administered 5 minutes prior to the test.
Main Results:
- Gastric glucose preloads more effectively reduced milk intake compared to intraperitoneal glucose injections.
- A preload of 2-deoxy-D-glucose (2-DG), which impairs glucose utilization, similarly decreased intake, suggesting a non-metabolic effect.
Conclusions:
- The findings support a preabsorptive osmotic mechanism, rather than a postabsorptive metabolic one, for glucose-induced intake inhibition in 18-day-old rats.
- This suggests that osmotic cues in the stomach play a significant role in early satiety signaling.
Abstract:
To determine if preloads of glucose act preabsorptively or postabsorptively to inhibit intake, 18-day-old rat pups were deprived for 24 h and then provided with sweet milk during a 30-min independent ingestion test. Five minutes before the test, gastric preloads (5% body weight, BW) or intraperitoneal injections (4 ml/kg BW) of isotonic, hypotonic, and hypertonic solutions of glucose or 2-deoxy-D-glucose (2-DG) were administered. There were two major results: First, preloads of 20% glucose decreased intake much more than intraperitoneal injections of 20% glucose. Second, a preload of 20% 2-DG, which decreases, rather than increases glucose utilization, was as effective as a preload of 20% glucose in decreasing intake. These results are consistent with a preabsorptive osmotic mechanism, but not with a postabsorptive metabolic mechanism, for mediating most, if not all, of the inhibition of intake 5 min after preloads of 20% glucose in rats on postnatal day 18 (P18).