Objective: With the advent of recombinant human GH (rhGH), it has become possible in controlled clinical studies to explore the effects of GH replacement in adults with GH deficiency. The objective of this study was to determine cardiovascular and renal effects of GH replacement in adults with GH deficiency.
Patients: We studied ten patients (one woman and nine men), mean age 47 years, with GH deficiency.
Design: The patients were given s.c. rhGH (Humatrope, Eli Lilly) 0.5 U/kg/week or placebo in a 6-month double blind cross-over study. Cardiac and renal function was measured before drug administration (baseline), before cross-over (i.e. after 6 months), and before termination of drug administration (after another 6 months). Analysis of variance was used to compare measurements during GH replacement with baseline and placebo measurements. One patient was excluded because of atrial fibrillation.
Measurements: Main outcome measures were glomerular filtration rate and Doppler-echocardiographic estimates of cardiac function and structure. Computerized exercise electrocardiogram, spirometry, and blood samples for analyses of plasma hormones were also obtained.
Results: Left ventricular function was maintained during GH replacement. However, left ventricular mass increased from 211 to 249 g (P < 0.05) mainly due to increased left ventricular dimension since wall thicknesses did not increase. The left atrium increased from 38 to 41 mm (P < 0.05), possibly because stroke volume increased from 92 to 118 ml (P < 0.0001) and cardiac output increased from 5.29 to 7.58 l/min (P < 0.05). Total peripheral resistance decreased from 18.9 to 12.4 mmHg min/l (P < 0.05), and diastolic blood pressure from 79 to 72 mmHg (P < 0.05). Heart rate at rest increased from 58 to 70 beats/min. Systolic blood pressure at rest was unchanged, as was systolic blood pressure during dynamic exercise. GH replacement did not cause ST-abnormalities. Serum creatinine decreased from 91.4 to 85.3 mumol/l (P < 0.05) and glomerular filtration rate increased from 89.6 to 99.8 ml/min (P < 0.01).
Conclusions: Thus, GH replacement has favourable cardiovascular and renal effects including increase of stroke volume and glomerular filtration rate with reduction of peripheral resistance.