SERUM-LIPOPROTEINS IN ACROMEGALY BEFORE AND 6-15 MONTHS AFTER TRANSSPHENOIDAL ADENOMECTOMY

OBJECTIVES Acromegaly is a rare disorder characterized by over-secreti on of GH, most often because of a pituitary adenoma. The disease is as sociated with disturbances in lipoprotein metabolism and an increased cardiovascular mortality. The aim of the present study was to investig ate whether treatment of acromegaly results in changes in serum concen trations of lipids and apolipoproteins, including lipoprotein(a) (Lp(a )). DESIGN Fourteen patients with clinical features of acromegaly and increased GH secretion were studied 1-10 months before and 6-15 months after transsphenoidal adenomectomy in an open study. PATIENTS Three p atients had diabetes mellitus before surgery and two of these patients had normalized serum glucose levels post-operatively. Mean and baseli ne plasma GH levels were determined from 24-hour GH profiles. Serum sa mples were taken in the morning after an overnight fast. All patients were normocholesterolaemic, and four patients were hypertriglyceridaem ic before treatment. RESULTS Mean plasma GH levels decreased from 34.5 +/- 7.4 to 2.1 +/- 0.4 mU/l (mean +/- SEM). Serum IGF-I, insulin and free T3 levels decreased and serum SHBG concentrations increased post- operatively. There was no effect of treatment on serum cholesterol con centrations, but serum triglyceride concentrations decreased. Serum ap olipoprotein (apo) B and apoE levels were unaffected by treatment. Ser um apoA-I levels increased and Lp(a) levers decreased post-operatively . CONCLUSIONS Successful treatment of acromegaly, resulting in normal mean GH values (<5mU/l) and/or normal responsiveness to TRH, have bene ficial effects on serum lipoproteins with increased serum apoA-I level s and decreased serum levels of triglycerides and Lp(a). These effects seem to be independent of improvement in glucose tolerance, since pat ients with diabetes mellitus before surgery and normal fasting blood g lucose levels post-operatively had similar lipoprotein responses to tr eatment as those with normal fasting blood glucose levels before surge ry.