Synthesis of prostaglandins by psoriatic skin

The biosynthesis of prostaglandins (PG) in biopsies from 9 patients with psoriasis was studied. The involved as well as the uninvolved psoriatic skin showed a statistically significant decrease of the ability to synthesize PG's. In PGE1-equivalents the concentration (mean +/- S.E.M.) was 4.41 +/- 0.48 ng/g wet weight in the psoriatic lesion, 5.41 +/- 0.64 ng/g wet weight in uninvolved psoriatic skin in the presence of exogenous arachidonic acid in the incubation medium as compared with 9.02 +/- 1.59 in normal human skin. When the skin was incubated without excess of exogenous precursor acid the activity formed was similarly significantly lower in psoriatic skin as compared with normal skin. A disturbed balance between E and F PG synthesis was not demonstrated, which might have accounted for the postulated altered intracellular ratio of cyclic AMP to cyclic GMP in psoriatic skin.