Comparison of glycogen store in two strains of rat and guinea-pig under fed and fasted conditions.

Glycogen content in the liver, skeletal muscle and heart has been determined in Sprague-Dawley (SD) and Wistar (W) rats and in tricoloured (T) and albino Dunkin Hartley (DH) guinea-pigs. The 12-week-old animals were studied under non-fasted or control conditions (N) and after 48 hr of fast (F48). Hepatic glycogen was higher in DH guinea-pigs (95.6 +/- 3.8 mg g-1) than in W (77.2 +/- 5.3 mg g-1) and SD (80.2 +/- 2.3 mg g-1) rats under N conditions. Mean values for the two strains were slightly higher in guinea-pigs than in rats. After fasting, hepatic glycogen was almost exhausted in the two species but was higher in W (1.5 +/- 0.08 mg g-1) and T (1.5 +/- 0.2 mg g-1) than in SD and DH (0.6 +/- 0.1 mg g-1). The content of glycogen in the anterior muscles of the thigh was comparable in the two strains of rat and guinea-pig, but was twice as high in the guinea-pigs (DH:15.1 +/- 0.6; T: 16.4 +/- 0.7 mg g-1) as in the rats (SD: 8.1 +/- 0.2; W: 7.1 +/- 0.5 mg g-1) under N conditions. In F48 animals, muscular glycogen decreased by 41-46% (rats) and 38-39% (guinea-pigs). Hepatic and extra-liver glycogen stores were calculated and found higher in the guinea-pigs than in the rats. The total utilization during fasting was larger in the guinea-pigs (6140 mg/kg body wt) than in the rats (4500 mg/kg body wt).(ABSTRACT TRUNCATED AT 250 WORDS)