Meeting Abstract
P3.116 Jan. 6 GLYCOGEN AND PROGLYCOGEN LEVELS ARE HIGHER IN MALE VERSUS FEMALE TROUT HEARTS BOLINGER, Mark T.*; BATTIPROLU, Pavan K.; RODNICK, Kenneth J.; Idaho State University bolimark@isu.edu
Glycogen, the storage form of glucose, is potentially an important energy source in the teleost heart. The heart of rainbow trout (Oncorhynchus mykiss) may become oxygen deficient during environmental hypoxia or vigorous swimming, and therefore rely on anaerobic glycolysis for ATP production. We have shown that male hearts store more glycogen than females, and glycogen can be significantly depleted in male (but not female) ventricle strips when stimulated to contract under hypoxia (PO2 = 10-20 mm Hg) for 60 min. It is also known that glycogen exists in two forms: 1) a more readily usable and intermediate form containing a high proportion of protein called proglycogen (acid precipitable), and 2) an acid soluble, macromolecular form. The purpose of our study was to determine whether sex differences exist in acid precipitable and soluble forms of glycogen in cardiac tissue. Glycogen content (both forms) was measured in frozen cardiac tissue from 10-12 month old immature males (n=10) and females (n=8) using the technique of Botker and colleagues (J Mol Cell Cardiol (1995) 27, 1325-1332). Results: Total glycogen was higher in males than females (5.52 � 1.83 vs. 3.38� 0.77 mg/g tissue, P<0.05), but the percentage of acid soluble (~80-85%) and precipitate forms (15-20%) of glycogen were identical between sexes. However, males had a higher absolute level of proglycogen than females (1.09 � 0.35 vs. 0.45 � 0.12 mg/g tissue, P<0.001). Conclusion: Higher levels of total glycogen and proglycogen in cardiac tissue from sexually immature males may reflect increased glycogen synthesis, degradation, and utilization versus female hearts. Funded by NIH P20RR16454, NSF-Idaho EPSCoR EPS-0447689, add NSF IOB-517669.
