Effects of isopropyl unoprostone and latanoprost on melanogenesis in mouse epidermal melanocytes.
OBJECTIVE
The authors sought to investigate the cellular mechanism of melanogenesis by prostaglandin antiglaucomatous compounds, isopropyl unoprostone (referred to as unoprostone) and latanoprost, and to quantitatively compare their effect on melanogenesis using cultured mouse epidermal melanocytes.


METHODS
M1, M2, and the acid of latanoprost, all of which are possible intraocular metabolites of unoprostone or latanoprost, were used. Tested prostaglandin-related compounds (final concentration range, 1 micromol/L-10 nmol/L) were administrated to the culture medium of purely cultured mouse melanoblasts, melan-A, once daily for 2 weeks. One micromole per liter prostaglandin F(2 alpha) solution was administered in parallel. Radioisotope assays were used to measure the total melanin synthesis and the activity of tyrosinase in converting tyrosine to L-3,4-dihydroxyphenylalanine, which is a rate-limiting reaction in melanogenesis. The effects of prostaglandin F(2 alpha), M1, or M2 on proliferation of melan-A were examined.


RESULTS
M1, M2, and acid of latanoprost but not prostaglandin F(2 alpha), significantly enhanced tyrosinase activity. M2 and acid of latanoprost more greatly enhanced tyrosinase activity than did M1. None of the tested compounds significantly altered the proliferation and total melanin synthesis of melan-A.


CONCLUSIONS
Both unoprostone and latanoprost enhanced tyrosinase activity. These prostaglandin-related compounds may influence the nature of melanin and result in pigmentation.
Kashiwagi
Kenji
K
Department of Ophthalmology, Yamanashi Medical University, Tamaho Yamanashi, Japan.
Tsukamoto
Katsuhiko
K
Suzuki
Michihiro
M
Tsukahara
Shigeo
S
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D015237:Dinoprost / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D000078404:Epidermal Cells; D000077338:Latanoprost; D008543:Melanins / Q000096:biosynthesis*; D008544:Melanocytes / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D011461:Prostaglandins F, Synthetic / Q000494:pharmacology*
D000959:Antihypertensive Agents; D008543:Melanins; D011461:Prostaglandins F, Synthetic; C072630:isopropyl unoprostone; D000077338:Latanoprost; D015237:Dinoprost; D014442:Monophenol Monooxygenase