SOMATOSTATIN PREVENTS THE POSTOPERATIVE INCREASES IN PLASMA AMINO-ACID CLEARANCE AND UREA SYNTHESIS AFTER ELECTIVE CHOLECYSTECTOMY

The importance of glucagon on postoperative changes in hepatic amino-n itrogen conversion were investigated in six patients undergoing electi ve cholecystectomy for uncomplicated gall stones. Patients were given infusions of somatostatin (bolus of 6 mu g/kg followed by continuous i nfusion of 6 mu g/kg/h) from induction of anaesthesia to the end of in vestigation, the first postoperative day (30 hours). Controls were 16 patients undergoing the same procedures omitting the somatostatin infu sion. In all patients blood concentration and plasma clearance of tota l alpha-amino-nitrogen, and amino acid stimulated rate of urea synthes is were measured. Elective cholecystectomy decreased blood alpha-amino -nitrogen concentration from mean (SEM) 2.9 (0.2) to 2.4 (0.1) mmol/l (p<0.05), increased the clearance of total alpha-amino-nitrogen from 5 .2 (0.3) to 6.6 (0.3) ml/s (p<0.05), and increased the rate of amino a cid stimulated urea synthesis from 27 (1) to 37 (2) mu mol/s (p<0.05) pointing to increased removal of amino-nitrogen at of plasma amino-nit rogen. of somatostatin prevented increase of glucagon for 24 hours aft er surgery, and prevented the negative changes in postoperative nitrog en homeostasis resulting from the postoperative changes in hepatic nit rogen conversion, suggesting glucagon as mediator. The exact mechanism remains in doubt, however, because of the multiple effects of somatos tatin.