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Spirometra mansonoides: effects of plerocercoid infection on glycogen deposition in rats
Abstract:
The effects of infection with plerocercoids of Spirometra mansonoides on tissue glycogen deposition of rats was determined. Hypophysectomized rats infected for two days had higher liver glycogen concentrations than controls and this effect was greatest after one week. Elevated liver glycogen associated with plerocercoid infection was observed in fed animals both at the beginning and at the end of the light period as well as after an overnight fast. Glycogen phosphorylase (1,4 alpha D glucan: orthophosphate alpha glucosyltransferase EC 2.4.1.1.) was inhibited but glucose-6-phosphatase (EC 3.1.3.9) was unaffected in the livers of infected hypophysectomized rats. While this effect is similar to actions of both growth hormone and insulin, plerocercoid infection had no influence on glycogen of cardiac or skeletal muscle at any time. Plerocercoid infection had no effect on the glycogen concentration of any tissue of intact rats.
Insights
Spirometra mansonoides plerocercoid infection significantly increases liver glycogen in hypophysectomized rats by inhibiting glycogen phosphorylase. This effect on glycogen deposition was not observed in intact rats or in cardiac and skeletal muscle.
Area of Science:
- Parasitology
- Biochemistry
- Physiology
Background:
- Spirometra mansonoides plerocercoids are known to affect host physiology.
- Glycogen deposition is a key indicator of metabolic regulation.
Purpose of the Study:
- To investigate the impact of Spirometra mansonoides plerocercoid infection on tissue glycogen levels in rats.
- To elucidate the specific mechanisms by which plerocercoid infection influences carbohydrate metabolism.
Main Methods:
- Hypophysectomized and intact rats were infected with plerocercoids.
- Liver glycogen concentrations were measured at various time points post-infection.
- Enzyme activities of glycogen phosphorylase and glucose-6-phosphatase were assessed.
Main Results:
- Infection led to significantly elevated liver glycogen in hypophysectomized rats, peaking at one week.
- Elevated liver glycogen was observed in fed and fasted states, and across the light cycle.
- Glycogen phosphorylase was inhibited, but glucose-6-phosphatase remained unaffected in infected hypophysectomized rat livers.
- No significant changes in glycogen levels were found in cardiac or skeletal muscle, or in any tissue of intact rats.
Conclusions:
- Spirometra mansonoides plerocercoids modulate liver glycogen deposition in hypophysectomized rats, likely via glycogen phosphorylase inhibition.
- The observed metabolic alterations are specific to the liver and dependent on the host's hormonal status (hypophysectomy).
- Plerocercoid infection does not impact glycogen stores in intact rats or peripheral tissues.