Effect of insulin and growth hormone on the synthesis of radiolabelled proteoglycans from cultured human arterial smooth-muscle cells

Abstract

Thogersen VB, Heickendorff L, Ledet T. Effect of insulin and growth hormone on the synthesis of radiolabelled proteoglycans from cultured human arterial smooth-muscle cells. Eur J Endocrinol 1996;134:326–30. ISSN 0804–4643 The present study focuses on the pathogenesis of increased frequency of large-vessel disease in diabetes. The diabetic arterial wall displays characteristic alterations of the extracellular matrix secreted by arterial smooth-muscle cells. The effects of insulin and growth hormone on the synthesis of sulphate-labelled proteoglycans and heparan sulphate proteoglycan were studied. Proteoglycans and heparan sulphate proteoglycan were obtained from the medium and the cell layer of cultured human arterial smooth-muscle cells grown in 5% human serum. Heparan sulphate proteoglycan was quantified using ethanol precipitation combined with specific enzyme degradation. Addition of insulin (0.01, 0.05 and 0.10 mU/ml) induced a significant accumulation of 35S-labelled proteoglycans in the cell layer (2p < 0.005 and 2p < 0.001). The relative amount of cell-associated heparan sulphate proteoglycan increased during insulin stimulation (2p < 0.05). Growth hormone stimulation (5.0 and 10.0 ng/ml) caused a significant decrease in the ratio between heparan sulphate proteoglycan and proteoglycan in the cell layer (2p < 0.02 and 2p < 0.01). whereas the distribution of proteoglycans between the cell layer and the medium was unaltered. Vibeke Bech Thogersen, Research Laboratory for Biochemical Pathology, Department of Pathology, Aarhus University Hospital, Kommunehospitalet, Nørrebrogade 44, DK-8000, Aarhus C, Denmark