Abstract
An important feature of acromegaly is a reduced action of insulin on hepatic gluconeogenesis
and peripheral glucosal disposal. Octreotide (SMS) exerts complex effects on hormonal
and metabolic regulations affecting glucose homeostasis. Eight patients with active
acromegaly despite surgical intervention (age 44.8 ± 3.5 years, BMI 27.3 ± 1.6 kg/m2, lean body mass (LBM) 70 ± 3.2%, blood glucose 5.24 ± 0.26 mmol/l, HbA1c ≤ 6.5%)
were investigated before and after 6 months of treatment with SMS in an open trial.
SMS was injected sc. at a dosage between 100 - 200 µg t.i.d. Mean GH and IGF1 levels
during SMS therapy were significantly reduced (GH 9.6 ± 1.9 ng/ml vs. 4.9 ± 1.3 ng/ml,
p < 0.05; IGF1 729.5 ± 84 ng/ml vs. 415 ± 49 ng/ml, p < 0.05). OGTT and euglycaemic-clamp-studies
were performed before and after 6 months of SMS treatment. The glucosal disposal rate
on average (insulin infusion rate 40 mU/m2/min) was not significantly changed following SMS treatment (McLBM before 3.60 ± 0.38,
after 3.95 ± 0.41 mg/kg LBM/min). There was a positive correlation (r = 0.620) between
the individual change of IGF1 and the change of McLBM. Additionally there was no significant
difference of serum basal insulin levels (0.19 ± 0.01 vs. 0.23 ± 0.06 nmol/l) as well
as basal C-peptide levels (0.19 ± 0.07 vs. 0.47 ± 0.04 nmol/l) before and with SMS
treatment. We therefore conclude that long-term treatment of acromegalic patients
with SMS, which achieves a successful reduction of GH and IGF1 levels, does not always
guarantee a significant improvement in glucose metabolism. Therefore treatment of
acromegalic patients requires individual adjustment of SMS-therapy as well as careful
monitoring of glucose metabolism.
Key words
Acromegaly - Octreotide - Euglycaemic Clamp - Insulin Resistance
