The role of oestradiol on the dermal penetration of phenol, alone or in a mixture, in ovariectomized rats.

The human body, as well as that of animals, is almost entirely covered by skin. As a result, skin is considered the first line of defence against various types of chemicals. Many factors can affect the rate of dermal penetration of these agents either by enhancing or decreasing penetration. The aim of this study was to demonstrate the effect of oestradiol on the dermal penetration of phenol, a major chemical found in industry and hazardous waste sites. The effect of oestradiol on the dermal penetration of phenol was assessed by applying (14)C-phenol alone or in combination with trichloroethylene (TCE) to dermatomed female and male rat back skin samples in flow-through diffusion cells for 16 hours. The penetration of phenol alone was significantly lower in the ovariectomized group compared with female controls. Oestradiol restoration increased the dermal penetration of phenol alone while TCE enhanced phenol penetration in the ovariectomized group to reach control values. When the ovariectomized group receiving testosterone was treated with phenol alone or with the phenol-TCE mixture, the dermal penetration of phenol resembled the control males. These findings revealed that oestradiol plays a major role in increasing the penetration of phenol either alone or in a mixture.