Aging is associated with decreased activity of delta-6-desaturase which converts linoleic acid to gamma-lino - lenic acid (GLA). This defect may alter plasma and membrane lipids and eicosanoid biosynthesis. Aim: We were interested in testing whether prolonged supply of GLA to old subjects could overcome the enzymatic defect and improve their metabolic and clinical status. Methods: Ten mobile old subjects, aged 83 ± 8 years, were investigated during initial hospitalisation and then discharged on ambulatory treatment of 3 months with a daily supplement of 320 mg of GLA, given as Epogam capsules (Scotia Pharmaceuticals Ltd) 4 x 2/ day. We measured arterial blood pressure, heart rate, renal function, plasma lipids, plasma and erythrocyte membrane essential fatty acids (C14–C22) and urinary prostaglandins (PG) 6-keto-F1a, E2, F2a and thromboxane (Tx) B2 before and after 30 and 90 days of treatment. Results: Exogenous supply of gamma-linolenic acid for 3 months significantly increased levels of dihomo-gam - ma-linolenic acid (p < 0.002) in plasma and to a smaller degree the level in erythrocyte membrane lipids. This treatment was associated with beneficial reduction of cardiovascular risk factors: decrease of arterial blood pressure, decrease of total plasma cholesterol, increase of HDL and apo A-I and stability of renal functions. Epogam treatment also increased renal prostaglandins, except 6-keto-PGF1a, but especially vasodilator PGE2. The treatment was well tolerated with good compliance. Conclusion: The dietary supply of specific essential fatty acids such as gamma-linolenic acid to old subjects may be of clinical importance.

        Key words: gamma-linolenic acid, prostaglandins, old subjects.