Pattern of plasma levels of cortisol, dehydroepiandrosterone and pregnenolone sulphate in normal subjects and in patients with homozygous familial hypercholesterolaemia during ACTH infusion.

The aim of this study was to determine whether patients with homozygous familial hypercholesterolaemia (FH) have impaired adrenal cortical function. Plasma levels of cortisol, dehydroepiandrosterone (DHA), pregnenolone sulphate (PS) and DHA sulphate (DHAS) were measured during and 8 h ACTH infusion in six controls and two patients with homozygous FH. The basal PS levels of both patients and the basal DHA level of one were abnormally low for age and pubertal stage. During ACTH infusion we observed in both patients: (1) a mild impairment of control response after sustained stimulation (P less than 0.002); (2) a clear impairment of PS response (values less than 2 SD of those in controls); (3) a clear impairment of DHA response (values less than 2 SD) until 4 h in the boy who was at pubertal stage 4 and whose response could be compared to controls; no increase at all in the affected girl (pubertal stage 2) at a stage where normal subjects respond with significant increase. These results suggest that patients with FH lack cholesterol for corticosteroid biosynthesis under maximal ACTH stimulation and that mild chronic ACTH stimulation due to a deficit in the cholesterol supply to adrenal cells might increase the conversion of delta 5 to delta 4-steroids. They provide further evidence to support the primordial role of low density lipoprotein (LDL)-cholesterol in adrenal steroidogenesis in vivo.