1. Department of Internal Medicine (Division of Endocrinology), Sahlgrenska University Hospital, S-41345 Göteborg, Sweden
2. ^*Department of Dermatology, Sahlgrenska University Hospital, S-41345 Göteborg, Sweden
3. ^†Department of Medical Nutrition and Department of Biosciences, Karolinska Institute, Novum, S-14157 Huddinge, Sweden

Correspondence: Claes Ohlsson, Division of Endocrinology, Department of Internal Medicine, Sahlgrenska University Hospital, S-41345 Göteborg, Sweden

Received 11 November 2001; Revised 24 April 2002; Accepted 16 June 2002.

Abstract

Estrogen is of importance for the regulation of hair growth and epidermal thickness. The effects of estrogen have predominantly been studied in females; however, recent studies demonstrate that estrogen also is critical for males. The aim of this study was to investigate the relative functional importance of estrogen receptor and estrogen receptor in the regulation of the hair follicle cycling and epidermal thickness in male mice. Seven month old transgenic male mice, lacking estrogen receptor (ERKO), estrogen receptor (BERKO), or both receptors (DERKO), were orchidectomized and treated for 3 week with 17-estradiol or vehicle. Orchidectomy induced a synchronized anagen phase of the hair follicles, which was inhibited by 17-estradiol treatment in wild-type and BERKO mice, but not in ERKO and DERKO mice. Furthermore, 17-estradiol treatment increased the thickness of epidermis in wild-type and BERKO mice, but not in ERKO and DERKO. This study demonstrates that estrogen is of importance for the regulation of hair follicle cycling and epidermal thickness in male mice. The effect on hair follicle cycling is caused by an estrogen receptor mediated inhibition of telogen–anagen transition and the effect of estrogen to increase epidermal thickness is associated with an estrogen receptor mediated increase in the proliferative rate of the keratinocytes in the basal cell layer of the epidermis.