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Table 6.

Changes in the units of activities per g tissueof glutamine synthetase(GS), carbamoylphosphate synthetase (CPS), ornithine transcarbamoylase (OTC),arginosuccinate synthetase + lyase (ASS+L) and arginase in the stomach ofH. signifer after progressive increase in salinity from 0.7‰ to 10‰ or 20‰

		Enzyme activity (μmol min⁻¹ g⁻¹ wet mass)
Enzyme	Substrate and effector	0.7‰ (control)	10‰	20‰
GS	-	6.03±0.86	10.5±2.90	6.84±0.68
OTC	-	8.40±0.86	6.71±1.92	5.25±0.72
ASS+L	-	0.42±0.09	0.45±0.11	0.46±0.04
Arginase	-	5.57±2.22	15.1±3.26	5.40±0.30
CPS	Glutamine	0.03±0.01	0.01±0.005	0.15±0.07^{^*},^{^†}
	Glutamine + AGA	0.10±0.05	0.03±0.01	0.45±0.18^{^*},^{^†}
	Glutamine + AGA + UTP	0.09±0.04	0.03±0.01	0.41±0.16^{^*},^{^†}

		Enzyme activity (μmol min⁻¹ g⁻¹ wet mass)
Enzyme	Substrate and effector	0.7‰ (control)	10‰	20‰
GS	-	6.03±0.86	10.5±2.90	6.84±0.68
OTC	-	8.40±0.86	6.71±1.92	5.25±0.72
ASS+L	-	0.42±0.09	0.45±0.11	0.46±0.04
Arginase	-	5.57±2.22	15.1±3.26	5.40±0.30
CPS	Glutamine	0.03±0.01	0.01±0.005	0.15±0.07^{^*},^{^†}
	Glutamine + AGA	0.10±0.05	0.03±0.01	0.45±0.18^{^*},^{^†}
	Glutamine + AGA + UTP	0.09±0.04	0.03±0.01	0.41±0.16^{^*},^{^†}

AGA, N-acetyl-l-glutamate; UTP, uridine triphosphate.

Results represent means ± s.e.m. (N=4).

Significantly different from 0.7‰ control condition at P<0.05.

†

Significantly different from 10‰ at P<0.05.

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