Serum total cholesterol and triglyceride levels were determined in forty-seven women with prolactinoma and in eighty-four age- and weight-matched control women. Oral glucose tolerance tests (OGTT) were performed and postheparin plasma lipoprotein lipase (LPL) and hepatic lipase (HL) activities were determined in twelve patients before and after transsphenoidal removal of the prolactinoma. The mean levels of serum cholesterol and triglyceride were significantly higher in patients than in controls. The 90% cut-off line of controls for serum cholesterol was exceeded by 36% and that for serum triglyceride by 23% of the patients. The triglyceride levels were raised only in patients with GH-deficiency whereas patients with normal GH secretion had normal triglyceride. Plasma LPL activity was significantly reduced whereas plasma HL activity was in the upper range of normal. After the removal of prolactinoma the serum prolactin levels decreased in all patients and seven started to menstruate. The oral glucose tolerance was improved and the plasma insulin response decreased. Serum lipid levels and the lipase activities, however, did not change.
Conclusion: prolactinoma is associated with metabolic abnormalities characterized by hyperlipidaemia, low plasma LPL activity and insulin resistance.