Role of endothelin-1 in hyperpigmentation in seborrhoeic keratosis.
Seborrhoeic keratosis (SK) is a benign epidermal tumour with a varying degree of pigmentation. We have recently demonstrated that endothelin-1 (ET-1) is a strong keratinocyte-derived mitogen and melanogen for human melanocytes in UVB-induced melanosis. To clarify the role of ET-1 in hyperpigmentation in SK, we have used immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) to see whether the production of ET-1 is accentuated in SK. Immunohistochemical analysis in SK (n = 7; acanthotic and deeply pigmented types) revealed marked immunostaining with anti-ET-1 in almost all basaloid and basal cells as compared with definite staining confined to basal cells in the perilesional normal controls. In parallel, RT-PCR of ET-1 mRNA demonstrated accentuated expression of ET-1 transcript in SK (n = 4) in comparison with that in the perilesional normal controls, accompanied by a similarly accentuated expression of tyrosinase mRNA. These findings suggest that ET-1 plays a part in the hyperpigmentation seen in SK.
Teraki
E
E
Department of Dermatology, Tokyo Women's Medical College, Japan.
Tajima
S
S
Manaka
I
I
Kawashima
M
M
Miyagishi
M
M
Imokawa
G
G
D000328:Adult; D000368:Aged; D019332:Endothelin-1 / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D005260:Female; D006801:Humans; D017495:Hyperpigmentation / Q000209:etiology* / Q000378:metabolism; D007150:Immunohistochemistry; D015603:Keratinocytes / Q000378:metabolism; D017492:Keratosis, Seborrheic / Q000150:complications* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D014442:Monophenol Monooxygenase / Q000235:genetics; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis
D019332:Endothelin-1; D012333:RNA, Messenger; D014442:Monophenol Monooxygenase