EFFECT OF LANREOTIDE, A SOMATOSTATIN ANALOG, ON UREA SYNTHESIS IN NORMAL MAN

The aim was to investigate the effect of lanreotide (Angiopeptin) on u rea synthesis. Lanreotide is a somatostatin analogue used in therapy t rials of certain cancers. Cancer patients are often protein catabolic, thus the effect of lanreotide on whole body protein metabolism is of importance. We investigated the effect of lanreotide by measuring urea nitrogen synthesis rate (UNSR) and blood a-amino nitrogen levels befo re, during and after a 30 min iv infusion of 25 g of an electrolyte-fr ee amino acid solution. 6 healthy male subjects were studied following , i) placebo (saline), ii) lanreotide 5 mu g/kg, and iii) lanreotide 8 0 mu g/kg. Lanreotide decreased urea nitrogen synthesis rate (mmol/h) during amino acid infusion significantly compared to saline, independe nt of dose of lanreotide (max +/- SE of urea nitrogen synthesis rate m easurements in each study: 117 +/- 8 mmol/h (saline), 85 +/- 10 mmol/h (high dose) and 85 +/- 12 mmol/h (low dose)). This occurred in spite of significantly higher plasma a-amino nitrogen following lanreotide ( peak +/- SE of a-amino nitrogen level in each study: 3.7 +/- 0.1 mmol/ l placebo versus 4.8 +/- 0.2 mmol/l low dose and 4.7 +/- 0.4 mmol/l hi gh dose (p < 0.01). We conclude that a single dose of lanreotide decre ases whole body urea nitrogen synthesis rate thereby conserving body p rotein. The results indicate that long term lanreotide therapy may not lead to further protein catabolism in cancer patients.