NO EVIDENCE FOR INVOLVEMENT OF THE GROWTH HORMONE INSULIN-LIKE GROWTH-FACTOR-I AXIS IN PSORIASIS/

We have examined whether alterations in the growth hormone/insulin-lik e growth factor-1 axis play a role in the pathogenesis of psoriasis. S erum, urine, full skin biopsies, and suction blister roofs were obtain ed from patients with psoriasis and from healthy controls, Serum conce ntrations of insulin-like growth factor-1 and insulinlike growth facto r binding protein-3 were measured by radioimmunoassay. Growth hormone- binding protein was measured by ligand-mediated immunofunctional assay . Growth hormone concentration in urine was measured by an immunometri c assay, and growth hormone receptor-gene expression was measured by R Nase protection assay or by quantitative reverse transcriptase polymer ase chain reaction in total RNA isolated from epidermal suction bliste r roofs, Serum concentrations of insulin-like growth factor-1 (249 +/- 12 mu g per liter, mean +/- SEM, n = 42, and 277 +/- 21 mu g per lite r, n = 9, for psoriatic patients and controls, respectively), insulin- like growth factor binding protein-3 (3.1 +/- 0.08 mg per liter, n = 4 2, and 3.3 +/- 0.22 mg per Liter, n = 9), growth hormone-binding prote in (344 +/- 65 pmol per liter, n = 10, and 311 +/- 83 pmol per liter, n = 9), urinary growth hormone excretion during 24 h (12.8 +/- 2.7 mu IU per 24 h, n = 12, and 12.3 +/- 1.6 mu IU per 24 h, n = 9), and epid ermal growth hormone receptor gene expression [32 +/- 12 x 10(3) mRNA transcripts per mu g total RNA (involved skin), n = 11, and 47 +/- 14 x 10(3) mRNA transcripts per mu g total RNA, n 9] were similar in pati ents and controls. For insulin-like growth factor-1 and insulin-like g rowth factor binding protein-3 the values in psoriatic patients were a lso similar to those in larger control groups, n = 195 and n = 400, re spectively. In addition, we found no evidence of local expression of g rowth hormone or prolactin in full skin punch biopsies from psoriatic involved skin by reverse transcriptase polymerase chain reaction. In c onclusion, our results suggest that alterations in the growth hormone/ insulin-like growth factor-1 axis do not play a major role in the path ogenesis of psoriasis.