In five totally pancreatectomized human subjects the secretion of gut-derived glucagons was stimulated by ingestion of a meal rich in fat and carbohydrates. Glucagon-like immunoreactivity in plasma, measured with an antiserum against the 6-15 sequence, increased fivefold in response to the meal. Glucagon like immunoreactivity measured with a antiserum against the C-terminal sequence was initially normal (12-13 pmol/l), increased slightly (to 20 pmol/l), and then decreased (to approximately 6 pmol/l). The chromatographic profile of glucagon-like immunoreactivity in plasma at maximum stimulation was studied after concentration by affinity chromatography. Both assay systems identified two peaks (at Kd-values of 0.30 and 0.60-0.65, and 0.30 and 0.70, respectively). The position at Kd 0.70 corresponds to that of glucagon 1-29. The same components may be identified in plasma from normal subjects. It is concluded that the human intestine is capable of generating all of the molecular forms of glucagon which normally are present in plasma.