The effect of oral ethanol ingestion on the diurnal neurotensin secretion in man.

Neurotensin is a tridecapeptide, present in the central nervous system and the gastrointestinal tract in man and animals. The affect of orally administered ethanol (1 g/kg body weight) on the neurotensin secretion over 24 hr period was studied in eight young healthy men. No significant circadian rhythm of neurotensin secretion was detected in the eight subjects studied. Ethanol produced a progressive rise in the plasma level of neurotensin reaching a maximum at 12:00 (13.8 +/- 8.6 pmol/l). At 12:00 and 14:00, the neurotensin concentrations were significantly higher than on the placebo day (p < 0.05). The secretion rate of neurotensin was determined approximately using the area under the curve method. Ethanol produced a transient rise in neurotensin secretion over the first 12 hrs period (08:00-20:00 h) after its administration (p < 0.02). The observation that ethanol increases transiently the neurotensin secretion in man supports the hypothesis that neurotensin may be involved in the biological effect of ethanol. The source of its secretion remains to be elucidated.