Endocrine Abstracts

Increased severity of periodontal disease has been reported in post-menopausal oestrogen deficient subjects, made worse by smoking. It was relevant to investigate this concept, using fibroblasts in culture and extrapolating the yields of androgen metabolites as an index of healing. The aim of this study is to establish the effects of nicotine (N), oestradiol (O) and the alkaline phosphatase inhibitor levamisole (L) on androgen metabolism in human gingival fibroblasts in this context (obtained local Ethical Committee approval). Fibroblasts were established in monolayer culture in Eagle's MEM and cells of the 5th - 9th passage were incubated in multiwell plates. Duplicate incubations were performed with confluent cultures in Eagle's MEM, using 14C-testosterone as substrate, in the presence or absence of optimal concentrations of O and L, alone and in combination, to demonstrate possible alkaline phosphatase mediated effects. Another series of experiments was performed to study the effects of nicotine, oestradiol and levamisole using 14C-T as substrate, to demonstrate the anabolic influence of oestradiol on nicotine mediated effects. At the end of a 24h incubation period, the medium was solvent extracted with ethyl acetate for metabolites, evaporated to dryness, separated by thin layer chromatography and quantified using a radioisotope scanner. The substrate 14C-testosterone was metabolised mainly to 5alpha dihydrotestosterone (DHT) and 4-androstenedione. The stimulatory effect of O on androgen metabolism (1.7-fold) was specifically inhibited by the alkaline phosphatase inhibitor levamisole by 32% - 1.5-fold (n=6; p<0.01). The inhibitory effects of nicotine (2-4-fold) on androgen metabolism at serial concentrations were slightly less inhibitory in the presence of oestradiol, ranging from 1.7-2.6-fold, and when levamisole was added to the incubation, there was specific inhibition in the yields of androgen metabolites of 1.7-5.3-fold (n=6; p<0.01) . These results suggest that alkaline phosphatase mediated androgen metabolism in fibroblasts can be stimulated by oestradiol and inhibited by nicotine.