suggest that cholesterol, in addition to ceramides, should be

applied to barrier-disrupted skin (6,7).

Our interesting finding was that cholesterol ointment decreased

OXA-induced CHR. As far as we know, there has been no report

which describes such a favourable effect for topical application of

cholesterol on a CHR. Real-time PCR and histological analyses

revealed the possible involvement of 11b-HSD1, which converts

cortisone to active cortisol, as a mechanism of cholesterol-induced

attenuation of CHR. As cortisol has potent anti-inflammatory

effects, the expression level of 11b-HSD1 may influence immune

responses (14). It has also been reported that 11b-HSD1 regulates

keratinocyte proliferation, but not differentiation (9,10). This

knowledge taken together suggests that cholesterol might attenuate

the contact hypersensitivity reaction partly via sustained expres-

sion of 11b-HSD1 in our mouse models. Thus, a cholesterol-

induced endogenous steroid might be an alternative therapy to the

use of exogenous steroids. Although further studies are required

to reveal the more precise mechanism, it might be speculated

that exogenous cholesterol application can improve and prevent

CHR.

AcknowledgementsThe authors thank Ms. Kumiko Mitsuyama, Ms. Ryoko Sugiyama and Ms.

Maiko Sugiura for secretarial work. We would also like to thank Mr. Kenju

Nishida and Ms. Eriko Nobuyoshi for assistance with research.

Funding sourceThis study was supported in part by a research grant from the Ministry of

Health, Labour and Welfare, Japan.

Conflict of interestsThe authors have no conflict of interests to declare. This study was per-

formed as joint research between industry and our university.

References1 Angelova-Fischer I, Mannheimer A C, Hinder A

et al. Exp Dermatol 2011: 20: 351–356.2 Elias P M. J Invest Dermatol 2012: 132: 2131–

2133.3 Imokawa G, Abe A, Jin K et al. J Invest Derma-

tol 1991: 96: 523–526.4 Janssens M, van Smeden J, Gooris G S

et al. J Invest Dermatol 2011: 131: 2136–2138.

5 Proksch E, Brandner J M, Jensen J M. ExpDermatol 2008: 17: 1063–1072.

6 Elias P M, Wakefield J S. Clin Rev Allergy Immu-nol 2011: 41: 282–295.

7 Elias P M. Clin Med Dermatol 2009: 2: 1–3.8 Tominaga M, Ozawa S, Tengara S et al. J Der-

matol Sci 2007: 48: 103–111.9 Terao M, Murota H, Kimura A et al. PLoS ONE

2011: 6: e25039.10 Terao M, Itoi S, Murota H et al. Exp Dermatol

2013: 22: 98–101.11 Iwai I, Han H, den Hollander L et al. J Invest

Dermatol 2012: 132: 2215–2225.

12 Feingold K R, Jiang Y J. Dermatoendocrinol2011: 3: 113–118.

13 Bayer M, Proksch P, Felsner I et al. Exp Dermatol2011: 20: 955–958.

14 Coutinho A E, Gray M, Brownstein D G et al.Endocrinology 2012: 153: 234–240.

Supporting InformationAdditional Supporting Information may be found inthe online version of this article:Data S1. Supplemental information of experimental

design.

DOI: 10.1111/exd.12291

www.wileyonlinelibrary.com/journal/EXDLetter to the Editor

Regional difference in sebum production by androgen susceptibilityin human facial skin

Young Joon Seo1, Zheng Jun Li1, Dae Kyoung Choi1, Kyung Cheol Sohn1, Hyeong Rae Kim1, Young Lee1,Chang Deok Kim1, Young Ho Lee2, Ge Shi3, Jeung Hoon Lee1 and Myung Im1

1Department of Dermatology, College of Medicine, Chungnam National University, Daejeon, Korea; 2Department of Anatomy, College of

Medicine, Chungnam National University, Daejeon, Korea; 3Department of Dermatology, The Affiliated Hospital of Guangdong Medical College,

Zhanjiang, China

Correspondence: Myung Im, MD, PhD, Department of Dermatology, Chungnam National University Hospital, 282-Munhwa-ro, Jung-Gu, Daejeon

301-721, Korea, Tel.: 82-42-280-7702; Fax: 82-42-280-7932; e-mail: im1177@hanmail.net

Abstract: Androgens are important hormones that influence sebum

production from the sebaceous glands. Human facial skin can be

categorized as T- and U-zones, which are areas with high and low

levels of sebum secretion, respectively. This study was performed to

investigate whether there are topographical differences in androgen

receptor (AR) expression related to regional variations in facial

sebum secretion. The results of in vivo analysis indicated a

statistically significant increase in AR expression in the sebaceous

gland T-zones compared with the U-zones. In vitro experiments

using human primary sebocytes also yielded similar results, with

higher levels of AR protein and mRNA expression in T-zones. The

results of this study suggested that differences in androgen

susceptibility may be an important factor influencing regional

differences in sebum production in human facial skin.

Key words: androgens – face – sebaceous glands – sebum

Accepted for publication 28 November 2013

70ª 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd

Experimental Dermatology, 2014, 23, 58–77

Letter to the Editor

BackgroundThe major function of the sebaceous glands is the secretion of

sebum, which lubricates the skin and protects it against infectious

organisms. However, excessive sebum production is one of the

major factors contributing to the development of acne lesions

(1,2). Variations in facial sebum secretion are related to topo-

graphical differences, demographic profiles, inherited factors and

environmental factors (3).

Facial areas can be categorized on the basis of sebum secretion

levels as T-zones (high sebum-secreting areas: forehead, nose,

chin) and U-zones (low sebum-secreting areas: both cheeks) (3,4).

Differences in the sebum secretion levels of the T- and U-zones

are commonly observed, which has been shown to be due to the

high density of sebaceous glands in the T-zones (5). However, it

has been suggested that another factor influencing sebaceous gland

biology may also contribute to regional differences in sebum

secretion. One previous study indicated that activity of 5a-reduc-tase type 1 exhibits regional differences in sebaceous glands and

may explain the anatomical localization of acne to the sebaceous

follicles of the face (6).

Androgens and androgen receptors (ARs) may play important

roles in several skin-related diseases, such as androgenetic alopecia

and acne vulgaris. Several studies have demonstrated the differen-

tial expression of AR in the dermal papilla cells and mesenchymal

cells from the vertex and occipital scalp and have indicated that

the differences in sensitivity of hair follicles to androgens could be

attributed to site-specific response differences to androgen hor-

mone in androgenetic alopecia (7,8). Androgens are also known

to play important roles in sebaceous gland physiology through

modulation of sebum production. In previous studies, ARs were

detected in the epithelial cells of the sebaceous glands (2,9,10).

The differences in sensitivity of sebaceous glands to androgens

may be attributable, at least in part, to their dissimilar AR expres-

sion levels.

Questions addressedIn this study, we postulated that topographical differences in AR

expression in sebaceous glands may be important contributing fac-

tors influencing regional variations in facial sebum production.

Therefore, in vivo and in vitro analyses were performed to investi-

(a)(b)

Figure 1. Expression of AR on human sebaceous glands. (a) Human sebaceousglands from the U-zone and T-zone of 10 fresh cadavers were assayed for AR byimmunohistochemical techniques. Scale bars = 100 lm. (b) Percentages ofimmunostained nuclei in basal or differentiated sebocytes were evaluated in severalsebaceous glands. Data represent the means � SE. Data were analysed byStudent’s t-test (*P < 0.05, **P < 0.01).

(a)

(b)

(c)

Figure 2. Expression of AR on human primary sebocytes. (a) Human primarysebocytes were isolated from each area (5 cheeks, 5 noses, 3 foreheads and 2chins). Intracellular lipids in primary sebocytes were detected by microscopy afterOil Red O staining and lipid levels in sebocytes calculated as percentages of thevalues in the U-zone. Scale bars = 20 lm. Western blotting analysis and RT-PCRanalysis of AR (b) and PPAR-c (c) expression in primary sebocytes. The protein andmRNA levels in sebocytes from the T-zone are expressed relative to those from theU-zone as a control. Data represent the means � SE. Data were analysed byStudent’s t-test (*P < 0.05, **P < 0.01).

ª 2013 John Wiley & Sons A/S. Published by John Wiley & Sons LtdExperimental Dermatology, 2014, 23, 58–77 71

Letter to the Editor

gate whether there are regional differences in AR expression

between the human facial skin of T-zones and of U-zones.

Experimental designFor Data S1, see ‘Supporting information’.

ResultsTo investigate the topographical differences in androgen susceptibil-

ity in human facial skin, we examined AR expression in the T- and

U-zones of the face from 10 fresh cadavers. Immunohistochemical

analyses indicated that ARs were present in all sebaceous glands

examined. However, immunostaining intensity was generally greater

in sebaceous glands of the T-zone than the U-zone (Fig. 1a). More-

over, the percentages of nuclei with positive staining in sebocytes

were also greater in the T-zone than the U-zone, especially in differ-

entiated cells (Fig. 1b). In the sebaceous glands from the U-zone,

the ARs were usually present in basal and early differentiated cells,

which was consistent with previous studies (11,12). However, in the

T-zone sebaceous glands, the intensity of receptor staining was

greatest in differentiated sebocytes, which had switched from a pro-

liferative mode to commence their specialized holocrine function,

suggesting that ARs play an important role in regulating sebocyte

differentiation, resulting in hyperseborrhea in the T-zone.

To explore the regional differences in AR expression in vitro,

we used primary human sebocytes obtained from the same

cadavers. It is well known that human sebocytes in vitro retain the

major characteristics of the sebaceous gland cells in vivo (13,14).

However, to confirm whether primary sebocytes from each area

showed the properties of sebum production of the T-zone and

U-zone in vivo, we first examined intracellular lipid droplet forma-

tion by Oil Red O staining; the results indicated increased lipid

accumulation in the cytoplasm of sebocytes from the T-zone, as

compared with the U-zone (Fig. 2a). After validation of the prop-

erties of primary sebocytes from each area, we assessed the pres-

ence of AR in human sebocytes by Western blotting and

semiquantitative RT-PCR to identify differences in AR expression

at the protein and mRNA levels. Mean level of AR protein was

4.8-fold higher in sebocytes from T-zone than U-zone. These site-

specific differences in AR expression were consistent with those at

the mRNA level, determined by RT-PCR, which indicated 5.2-fold

higher expression in sebocytes from the T-zone (Fig. 2b). Finally,

we evaluate the levels of PPAR-c, a potential modulator of lipid

production in human sebocytes (14,15), showed results similar to

those for AR expression (Fig. 2c).

ConclusionsIn this study, we evaluated the regional differences in sebum pro-

duction from the viewpoint of androgen receptors (ARs). Andro-

gens induce sebaceous gland growth and differentiation after

binding to AR. AR may enhance lipogenesis in sebocytes by

increasing the expression of fibroblast growth factor receptor 2 or

sterol-regulatory element-binding proteins (16,17). On the other

hand, AR antagonists or degradation enhancer inhibits sebocyte

proliferation, sebum production and reduce the size of sebaceous

glands (18,19). On the basis of previous reports, we postulated

that topographical differences in AR expression may influence

regional variations in facial sebum secretion. In vivo analysis using

facial skin from cadavers demonstrated higher levels of specific

nuclear staining for AR in sebaceous glands from the T-zone,

especially differentiated sebocytes. These in vivo findings were sup-

ported by those of in vitro experiments using primary human seb-

ocytes cultured from the same donors. The levels of AR protein

and mRNA were also increased in sebocytes from the T-zone, as

compared with the U-zone.

In summary, the results of the present study indicated and fur-

ther supported the suggestion that the sebaceous glands in the face

are androgen hormone-regulated organs with site-specific response

differences. This study suggested that differences in androgen sus-

ceptibility related to variations in AR expression are important

factors influencing regional differences in sebum production in

human facial skin. Further studies of cofactors required for the

actions of androgens and AR regional expression in acne lesions

are warranted to gain further understanding of the effects of AR

on regional differences in sebum secretion.

AcknowledgementsThis study was supported by a grant of the Traditional Korean Medicine

R&D Project, Ministry of Health & Welfare, Republic of Korea (HI13C0615).

Y.J.S, Z.J.L, D.K.C and M.I. performed the research, and J.H.L and M.I analy-

sed the data. Y.H.L contributed the cadavers for the study. All authors con-

tributed substantially to writing and editing the paper.

Conflict of interestsThe authors have declared no conflicting interests.

References1 Smith K R, Thiboutot D M. J Lipid Res 2008: 49:

271–281.2 Kurokawa I, Danby F W, Ju Q et al. Exp Derma-

tol 2009: 18: 821–832.3 Youn S W, Na J I, Choi S Y et al. Skin Res Tech-

nol 2005: 11: 189–195.4 Park S G, Kim Y D, Kim J J et al. Skin Res Tech-

nol 1999: 5: 189–194.5 Greene R S, Downing D T, Pochi P E et al. J

Invest Dermatol 1970: 54: 240–247.6 Thiboutot D, Harris G, Iles V et al. J Invest Der-

matol 1995: 105: 209–214.7 Kwon O S, Han J H, Yoo H G et al. J Dermatol

Sci 2004: 36: 176–179.

8 Yoo H G, Won C H, Lee S R et al. Arch Derma-tol Res 2007: 298: 505–509.

9 Liang T, Hoyer S, Yu R et al. J Invest Dermatol1993: 100: 663–666.

10 Zouboulis C C. Dermatoendocrinol 2009: 1:77–80.

11 Fritsch M, Orfanos C, Zouboulis C C. J InvestDermatol 2001: 116: 793–800.

12 Zouboulis C C, Chen W, Thornton M et al.Horm Metab Res 2007: 39: 85–95.

13 Zouboulis C C, Xia L, Akamatsu H et al. Derma-tology 1998: 196: 21–31.

14 Hinde E, Haslam I S, Schneider M R et al. ExpDermatol 2013: 22: 631–637.

15 Downie M M T, Sanders D A, Maier L M et al.Br J Dermatol 2004: 151: 766–775.

16 Melnik B C. Dermatoendocrinol 2009: 1: 141–156.17 Melnik B C. J Dtsch Dermatol Ges 2010: 8:

105–114.18 Ye F, Imamura K, Imanishi N et al. Skin Pharma-

col 1997: 10: 288–297.19 Lai J J, Chang P, Lai K P et al. Arch Dermatol

Res 2012: 304: 499–510.

Supporting InformationAdditional Supporting Information may be found inthe online version of this article:Data S1. Materials and methods.

72ª 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd

Experimental Dermatology, 2014, 23, 58–77

Letter to the Editor