Age-related Melanogenesis in the Eye of Mice, Studied by Microautoradiography of3H-methimazole, a Specific Marker of Melanin Synthesis

Lindquist, Nils Gunnar; Larsson, Bengt; Stjernschantz, Johan; Sjöquist, Birgitta

doi:10.1006/exer.1998.0513

Cited by 27 publications

(22 citation statements)

References 13 publications

(11 reference statements)

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“…36 In contrast to the monkey, active melanin synthesis has been observed in the iridial pigment epithelium of the untreated adult mouse eye. 37 The increase in the amount of eumelanin without a change in pheomelanin in the iris stroma found during latanoprost treatment in cynomolgus monkeys confirms that latanoprost has a eumelanogenic effect and argues against local migration of melanocytes as the cause for darkening of the iris. 38 …”

Section: In Vitro Evidencementioning

confidence: 52%

Latanoprost and Pigmentation

2004

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Latanoprost is a prostaglandin analogue with well-established efficacy in the treatment of open-angle glaucoma and ocular hypertension. Once-daily administration of this drug for up to 5 years is generally well tolerated both locally and systemically. While most reported side effects have been classified as mild in intensity, an increase in iris, eyelash, and periocular pigmentation has been associated with prostaglandin analogue use in some patients. Follow-up studies of patients withdrawn from latanoprost treatment suggest that the increased iridial pigmentation is irreversible while changes in eyelash and periocular skin pigmentation are reversible after cessation of therapy. Concern as to whether latanoprost affects proliferation of iridial melanocytes or other cellular components prompted investigation into its mechanism of action. All available evidence from in vitro, in vivo, and clinical studies suggests that latanoprost does not induce melanocyte proliferation. Morphologic study of human peripheral iridectomy specimens did not reveal any significant latanoprost-induced pathologic change in the iris. There was no evidence of melanin granules blocking the outflow pathways in treated patients. Stimulation of melanogenesis in iridial melanocytes, perhaps through an effect on tyrosinase, appears to account for induction of melanin production. Additional studies are in progress to further elucidate the mechanism of latanoprost-induced increased iridial pigmentation.

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Section: In Vitro Evidencementioning

confidence: 52%

Latanoprost and Pigmentation

2004

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“…It was previously thought that the melanocytes in the iris are not capable of forming melanin in the adult individual, or at least that the turnover of melanin in the adult iris is extremely low (reviewed by Schraermeyer, 1993). In microautoradiographic studies in mice using a false melanin precursor G-$H-methimazole (Olander et al, 1983) we observed that there seems to be an active melanin synthesis in the adult iris of the mouse both in the iridal melanocytes and in the iridal pigment epithelium (Lindquist et al, 1998). Earlier studies on the melanogenesis in the eye of vertebrates have given conflicting results (Miyamoto and Fitzpatrick, 1957 ;Fitzpatrick and Kukita, 1959 ;Hu and Montagna, 1971 ;Lindquist, 1974 ;Dryja et al, 1977 ;Boulton et al, 1990 ;Benedito et al, 1995 ;Ansorge et al, 1996).…”

Section: Introductionmentioning

confidence: 76%

Increased Pigmentation of Iridial Melanocytes in Primates Induced by a Prostaglandin Analogue

Lindquist

Larsson

Stjernschantz

1999

Experimental Eye Research

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“…While the UV-induced increase in production of melanin is a wellknown adaptive response of normal skin melanocytes in vivo, no such reaction of ocular pigmented cells has yet been convincingly documented. Non-induced melanogenesis has been demonstrated in uveal melanocytes in vitro [11,15,19]. The turnover of melanin, however, is very slight [23].…”

Section: Introductionmentioning

confidence: 98%