Glucose homeostasis in acromegaly: effects of long-acting somatostatin analogues treatment.
OBJECTIVE
Acromegaly is a syndrome with a high risk of impaired glucose tolerance (IGT) and diabetes mellitus (DM). Somatostatin analogues, which are used for medical treatment of acromegaly, may exert different hormonal effects on glucose homeostasis. Twenty-four active acromegalic patients were studied in order to determine the long-term effects of octreotide-LAR and SR-lanreotide on insulin sensitivity and carbohydrate metabolism.


METHODS
Prospective study.


METHODS
We studied 24 patients with active acromegaly, 11 males and 13 females, aged 50.7 +/- 12.7 years, body mass index (BMI) 30.1 +/- 4.8 (kg/m2).


METHODS
All patients underwent an oral glucose tolerance test (OGTT) and 12 also had an euglycaemic hyperinsulinaemic clamp. All patients were evaluated at baseline and after 6 months of somatostatin analogues therapy.


RESULTS
Acromegalic patients showed low M-values in respect to the control group at baseline (P<0.05), followed by a significant improvement after 6 months of therapy (P<0.005 vs. baseline). Serum glucose levels at 120 min during OGTT worsened (P<0.05) during somatostatin analogs therapy in patients with normal glucose tolerance, but not in those with impaired glucose tolerance or diabetes mellitus. This was associated with a reduced (P<0.05) and 30 min delayed insulin secretion during OGTT. Also, HbA1c significantly deteriorated in all subjects after treatment (4.7 +/- 0.6% and 5.1 +/- 0.5%, basal and after six months, respectively, P<0.005).


CONCLUSIONS
In acromegalic patients, somatostatin analogues treatment reduces insulin resistance, and also impairs insulin secretion. This may suggest that the use of oral secretagogue hypoglycaemic agents and/or insulin therapy should be considered rather than insulin sensitizers, as the treatment of choice in acromegalic patients who develop frank hyperglycaemia during somatostatin analogues therapy.
D000172:Acromegaly / Q000188:drug therapy* / Q000378:metabolism; D000328:Adult; D000368:Aged; D019540:Area Under Curve; D001786:Blood Glucose / Q000032:analysis; D005260:Female; D005947:Glucose / Q000378:metabolism*; D015309:Glucose Clamp Technique / Q000379:methods; D018149:Glucose Intolerance / Q000188:drug therapy / Q000378:metabolism; D005951:Glucose Tolerance Test; D006706:Homeostasis / Q000187:drug effects*; D019382:Human Growth Hormone / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008297:Male; D008875:Middle Aged; D015282:Octreotide / Q000627:therapeutic use*; D010456:Peptides, Cyclic / Q000627:therapeutic use*; D011446:Prospective Studies; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000627:therapeutic use*
D001786:Blood Glucose; D007328:Insulin; D010456:Peptides, Cyclic; C060347:lanreotide; D019382:Human Growth Hormone; D013004:Somatostatin; D007334:Insulin-Like Growth Factor I; D005947:Glucose; D015282:Octreotide