Effect of alpha-1-blockade by prazosin on blood sugar, insulin and glucagon levels in normals and non-insulin dependent diabetics.

The AA. studied the glycometabolic activity of prazosin, a hypotensive drug with an adrenergic blocking activity of alpha-1-selective type. Twenty-two moderately hypertensive subjects were studied. Their ages ranged from 37 to 57 years; 10 of the patients had non-insulin dependent diabetes mellitus. After overnight fasting every patient underwent an oral glucose test (g 100) at 09:00. Blood samples were withdrawn at 0, 30, 60, 90 and 120 minutes. Each patient was then given in randomized and double-blind fashion placebo or prazosin (4 mg, 2 pills of Minipress Pfizer per day) for the following 7 days; then another glucose load was administered. Glucose (enzymatic method), insulin and glucagon (RIA method) were measured in each blood sample. In non diabetic subjects glucose levels (60, 90, 120 min and total area) after oral glucose and prazosin were statistically higher (p less than 0.05, p less than 0.01, p less than 0.05) than after glucose only. No significant difference between the two curves was observed in the diabetic group. IRI levels in normal subjects were statistically higher after 120 min and in the total area, while no evident changes were noted in the diabetic group. The glucagon curve seen after oral glucose was not modified by prazosin in either group.