Ureagenesis and gluconeogenesis might be integrated processes and, thus, a trial with 4 multicatheterized wethers was conducted to measure the impact of the mesenteric infusion of different N compounds on liver net flux of urea and glucose. The trial was conducted as a 4 × 4 Latin square with 210-min daily periods. The blood flow through portal-drained viscera (PDV) and total splanchnic tissues (ST) was determined by downstream dilution of 15 g/L p-aminohippurate (PAH) infused continuously (1.5 mL/min) into the mesenteric vein. In parallel, wethers were continually infused into the mesenteric vein with a saline (0.15 M NaCl) solution during 90 min followed by the infusion, during more 120 min, of either: saline (control), 0.25 M NH₄HCO₃, 0.25 Ml-alanine or 0.125 Ml-arginine, all of them infused at a rate of 1.5 mL/min to provide 375 µmol N/min. Throughout infusion periods simultaneous arterial, portal and hepatic blood samples were taken at 30 min interval and analyzed for PAH, urea and glucose. Liver net flux was the difference between TS and PDV values. The PROC MIXED of SAS was used for variance analysis, which generated a residual error. The hepatic net flux obtained during treatment infusion (i.e., 90 to 210 min) was compared with that of control period (i.e., first 90 min) within each treatment by F test. Hepatic net flux of urea was increased only for NH₄HCO₃ whereas glucose net flux was increased only when alanine was infused into the mesenteric vein (Table 1). In conclusion, no clear relationship between ureagenesis and gluconeogenesis was observed in wethers. Table 1. Hepatic net flux (mg/h) of metabolites by wethers infused with saline (NaCl) or with 375 µmol N/min of different N compounds into the mesenteric vein

Item	Time (min)1	Infusion treatments				SEM
NaCl	Ammonia	Alanine	Arginine
Urea	0-90	431	437	585	538	68.9
	90-210	450	752	602	519	89.1
P*		0.796	0.044	0.888	0.889
Glucose	0-90	2817	4220	3042	3799	540.5
	90-210	3825	4648	5502	4306	395.5
P*		0.194	0.757	0.018	0.556

¹Saline solution was used through the first 90 minutes in all treatments. *Probability of the difference between 90-210 vs.0-90 min means.