Endocrine Abstracts

Introduction: Growth hormone (GH) is a lipolytic hormone with pleitropic metabolic functions. The effects of long-term GH substitution in pituitary insufficient patients with growth hormone deficiency (GHD) on lipid metabolism and bone mineralisation (BMD) have yet to be ascertained.

Methods: We measured fasting total cholesterol, low density lipoprotein (LDL), high density lipoprotein (HDL), triglycerides, glucose and insulin concentrations in 52 GHD on constant hormone replacement for pituitary insufficiency (21f/31m, median age 51.5 years (27–82)). Twenty-two GHD were additionally on constant GH substitution (GH-Sub) for at least 2 years (median 10 years (2–42 years)). Thirty age- and BMI-matched GHD had not been substituted for at least 2 years (non-Sub). Five GH-Subs and 4 non-Subs received medical treatment for lipid metabolism (GH-Sub: 4 statine, 1 fibrate, non-Sub: 3 statine, 1 fibrate). One non-Sub was on bisphosponate therapy for treatment of osteoporosis. BMD was measured by Dual-Energy-X-Ray-Absorptiometry. Osteoporosis was defined according to the World-Health-Organization.

Results: Total cholesterol, LDL, HDL and triglycerides were not significantly different between GH-Sub and non-Sub (total cholesterol 214 mg/dl (162–295) vs 205 mg/dl (149–309), LDL 133 mg/dl (85–218) vs 129 mg/dl (65–218), HDL 57 mg/dl (31–84) vs 48 mg/dl (14–93), triglyceride 123 mg/dl (55–292) vs 134 mg/dl (41–923)). Glucose was significantly lower for GH-Sub than non-Sub (87 mg/dl (71–103) vs non-Sub 89 mg/dl (71–113), P<0.05), whereas insulin did not differ significantly (10 μE/ml (4–42) vs non-Sub 10 μE/ml (4–63)). Furthermore, BMD and T-scores did not differ significantly between the two groups (BMD: GH-Sub: 1.18 g/cm² (0.97–1.39) vs 1.14 g/cm² (0.92–1.32), T-score: GH-Sub: −0.3 (−2.4–2) vs −0.2 (−2.7–1.3)). The percentage of patients having osteopenia was higher in GH-Sub compared to non-Sub (36 vs 0%), but more non-Sub had significant osteoporosis (20 vs 7%).

Conclusion: Long-term GH substitution alone does not seem to significantly impact on lipid metabolism and BMD in patients with pituitary insufficiency.