Development of Hyperlipidemia Associated with Increased Lipolytic Response of Isolated Adipose Tissue Cells Following Prolonged Stimulation by an Ectopic Pituitary Tumor[*]

Abstract

Implantation of MtT-F4 tumor, a mammotropic tumor that secretes large quantities of ACTH, GH and prolactin, into male Fisher rats induced the development of hyperlipidemia. Free fatty acid, triglyceride and cholesterol levels in the plasma were significantly increased at 31 days after tumor implantation. Blood glucose and glycerol levels remained normal, while uric acid concentration in the blood was significantly decreased. The lipolytic response of isolated adipose tissue cells to ACTH was significantly higher in cells derived from rats bearing an MtT-F4 tumor for 31 days than from their corresponding controls. However, the activity of adenylate cyclase in fat cells stimulated with ACTH was not significantly higher in cells derived from tumor bearing rats than in cells from control rats.

Key words

Hyperlipidemia - Lipolysis - Adenylate Cyclase - ACTH - MtF-F4 Tumor - Blood Uric Acid

1 This work was supported by grants from the Quebec Heart Foundation, the Medical Research Council of Canada and the National Cancer Institute of Canada.

1 This work was supported by grants from the Quebec Heart Foundation, the Medical Research Council of Canada and the National Cancer Institute of Canada.

2 C.G. is a fellow of the Medical Research Council of Canada.