Psoralen Action on Melanogenesis

Pigmentation induced by psoralen drags plus UV irradiation is evidently due to an increase of functioning melanocytes, increase in the number of melanosomes, increase in the activity of the enzyme, and in the transfer of melanin granules to malpighian cells (196). 

Studies of hypophysectomized todes by Indian workers revealed that psoralen in the absence of light stimulates tyrosinase activity in the skin and liver of toads (13,14). Carter et al. (34) found a 2- to 3-fold increase in tyrosinase activity as compared to psoralen alone after UV irradiation of Cloudman melanoma containing TMP. Borkovic et al. (20), on the basis of their experimental results on melanization with TMP, suggested that TMP may be used in a clinical setting without UV radiation for the 

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