CONTRASTING RENAL AND METABOLIC EFFECTS OF ALPHA-ADRENERGIC-BLOCKADE AND BETA-ADRENERGIC-BLOCKADE IN MILDLY HYPERTENSIVE TYPE-1 (INSULIN-DEPENDENT) DIABETIC SUBJECTS

The impact of doxazosin and atenolol on renal function and metabolic c ontrol in mildly hypertensive type I diabetic subjects was examined du ring a double-blind cross-over study. During each 3-month treatment ph ase, dosage was adjusted to achieve the target age- and gender-derived 50th centile seated diastolic pressure. A comparable reduction in sys tolic (12 mmHg) and diastolic (9/8 mmHg) blood pressure was achieved w ith doxazosin (mean dose 2.8 mg) and atenolol (mean dose 130 mg). Over night albumin excretion rates only fell significantly with doxazosin ( from 6.8 (geometric mean) to 5.2 mu g min(-1), p=0.005). Neither treat ment altered retinol binding protein excretion, plasma creatinine or c atecholamines. Supine plasma renin activity was reduced by atenolol (f rom 8.5 to 4.4 pmol l(-1) min(-1)), but not by doxazosin (p=0.018). Re nal plasma flow fell with atenolol in contrast to doxazosin (-80 vs -1 3 ml min(-1) 1.73 m2(-1), p=0.048). Fasting plasma glucose in HbA(1) d id not alter, but serum fructosamine rose following atenolol treatment , in comparison to doxazosin (+23 vs -10 nmol l(-1), p=0.013). Serum l ipid and lipoprotein concentrations were not significantly different, but the total : HDL cholesterol ratio rose significantly with atenolol , in comparison to doxazosin (p=0.008). Despite comparable hypotensive efficacy in mildly hypertensive type 1 diabetes, atenolol and doxazos in had different effects on renal function, plasma renin activity, sho rt term blood glucose control, and the distribution of cholesterol wit hin atherogenic and anti-atherogenic lipoprotein particles.