Fig. 1. Changes in glycolytic enzyme specific activities (i.u. mg^-1 protein) in tissues of Fundulus grandis held under normal and reduced oxygen levels for 4 weeks at 27°C. The y axis represents the percentage change in the mean value for each enzyme measured from hypoxic fish relative to the normoxic value for (A) skeletal muscle, (B) liver, (C) heart and (D) brain. Asterisks indicate significant differences between mean specific activity values from normoxic and hypoxic groups (^*P0.05; ^**P0.001; see Table 1). HK, hexokinase; PGI, phosphoglucoisomerase; PFK, phosphofructokinase; ALD, aldolase; TPI, triose phosphate isomerase; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; PGK, phosphoglycerokinase; PGM, phosphoglyceromutase; ENO, enolase; PYK, pyruvate kinase; LDH, lactate dehydrogenase.