Endocrine Abstracts

Aims

Nicotine (N) has detrimental effects on fibroblasts compounding those of AGE in uncontrolled diabetes. The impact of the antioxidant glutathione (G) is investigated to clarify mechanisms involved, using 5 alpha dihydrotestosterone (DHT) as a hormone marker of healing.

Methods

Human gingival fibroblasts in confluent culture were incubated in Eagle’s MEM, with 14C-testosterone / 14C-4-androstenedione and optimal microgram concentrations of AGE50, N250 and G3 individually and in combination in order to study potential oxidative effects and their modulation by glutathione. At 24 h the medium was analysed for formed metabolites using thin layer chromatography and radioisotope scanning.

Results

When the effects of the agents AGE, N and G3 were tested, there were 10% & 20% reductions in the yields of DHT in response to AGE and N alone, with values reaching those similar to controls in response to a combination with G (n=6; p<0.05). A combined incubation of AGE plus N resulted in a further 20% decrease in yields to that of AGE alone. There was not much change in the yields of diols while the yields of androstanedione and 4-androstenedione showed an inverse relationship (not shown). When 14C-4-androstenedione was used as substrate, AGE and N caused 21% and 40% reductions respectively in the yields of DHT. G alone resulted in yields of DHT similar to controls. AGE+N caused a 30% decrease over AGE alone. When G was added to this combination there was a 30% increase in yields over those for AGE+N (n=6; p<0.01). There was not much change in the diols. Testosterone showed an inverse relationship with AGE & N, with no further changes in the combinations.

Conclusions

The antioxidant glutathione was effective in overcoming the inhibitory effects of AGE and nicotine in combination. This has implications on therapeutic strategies for overcoming oxidative stress.