359 Atherosclerosis, 33 (1979) 359-364 0 Elsevier/North-Holland Scientific Publishers, Ltd. REGULATION OF CHOLESTEROL SYNTHESIS IN SKIN FIBROBLASTS DERIVED FROM OLD PEOPLE V A LERIE SHAKESPEARE 1 and ANTHONY D. POSTLE * 1 School of Biochemical and Physiological Sciences and 2 Child Health Unit, University of Southampton, Southampton SO9 3TU (Great Britain) (Received 22 January, 1979) (Accepted 16 February, 1979) summary Sterol synthesis from radioactive acetate and the suppression of this syn- thesis by human low density lipoprotein (LDL) have been investigated in skin fibroblast strains derived from infant donors and from donors over the age of 70 years. The activity of the enzyme hydroxymethylglutaryl-CoA reductase and its repression by LDL has also been investigated in these fibroblast strains and in senescent cells of the foetal lung cell strain MRC-5. No age-related differ- ences could be detected either in repression of [ 3H]acetate incorporation ‘by LDL, or in repression of HMG-CoA reductase activity. Key words: Ageing - Cholesterol - Fibroblasts Introduction A clear correlation has been shown to exist between the incidence of arterial atherosclerosis and increasing age, even when ethnic and geographical consider- ations are taken into account [ 11. It has also been observed that the inherited premature ageing conditions progeria and Werner’s syndrome are associated with an increased incidence of atherosclerosis at an early age [2]. Much experimental evidence is available which suggests that ageing is accompanied by the synthesis of defective enzymes [ 3,4]. Such faulty synthesis could contribute to the development with age of disturbances in the regulation of cholesterol metabolism leading, in turn, to the development of hypercholesterolaemia, a well established risk factor for atherosclerosis [ 51. This work was supported by the British Heart Foundation.