Prolactin in diabetic praecoma.

Prolactin has been suggested to exert a diabetogenic action in animal and man. Thus this report is concerned with the changes of serum prolactin in severely hyperglycaemic patients in a praecomatous state (n = 12). Basal serum prlactin levels were 12.0 +/- 3.4 (SE) ng/ml on admission and well within the normal range (less than 20 ng/ml). Rehydration of the patients which induced a significant fall in blood glucose (31.2 +/- 2.1 to 21.6 +/- 2.9 mmol/l) and in serum osmolality (336 +/- 9 to 316 +/- 10 mosmol/kg H2O) was however without any effect in serum prolactin concentration (9.9 +/- 2.5 ng/ml at the end of the rehydration period). We conclude that prolactin is not involved in the severe endocrine and metabolic derangements seen in diabetic praecoma; its secretion does not seem to be markedly altered by acute changes in blood glucose and serum osmolality.