Effect of oral fat on plasma levels of neurotensin and neurotensin fragments in humans

The effect of ingestion of fat (Lipomul 1 g/kg) on the circulating levels of neurotensin (NT^1–3) and amino-terminal fragments (NT^1–8, NT^1–11) and carboxy-terminal fragment (NT^8–13) of NT were investigated in six healthy male volunteers. NT and NT fragments were extracted from plasma collected at 0, 15, 30, and 60 min after ingestion of fat, and the plasma levels of NT^1–13 and NT fragments were characterized using high-pressure liquid chromatography and radioimmunoassay techniques. Significant elevations of plasma levels of NT^1–8, NT^1–11, and NT^1–13 were observed at 15, 30, and 60 min after fat ingestion. The maximum elevations were 273% for NT^1–8, 234% for NT^1–11, and 54% for NT^1–13. NT^8–13 levels failed to rise significantly when compared to basal levels. These findings indicate that both the aminoterminal and carboxyterminal fragments of NT are either released along with intact NT or are formed as metabolites from NT^1–13 in response to ingestion of fat in man.Dr. Upp was awarded a fellowship grant from the American Cancer Society Texas Division.Supported by grants from the National Institutes of Health (5R37 DK 15241, PO1 DK 35608, MO1 RR00073) and a grant from the American Cancer Society (PDT-220).