Therapy which impairs glucose tolerance: e.g., niacin, thiazide diuretics, phenytoin, excess thyroxine or psychotropic drugs within 1 month of phase I, oral contraceptives within 6 weeks of phase I, glucocorticoid treatment within the past 6 months (or one year if treatment lasted over 2 weeks), Beta blockers/agonists (e.g., terbutaline) within 2 days of phase I;