Melanomacrophages and melanocytes are able to modify pigment intensity on the body surface as a response to temperature change, hibernation, hypoxia, infection, oxidative stress and exogenous use of hormones. This study evaluated the effect of the sex hormones 17β-estradiol and testosterone cypionate on the hepatic melanomacrophages and testicular melanocytes of Eupemphix nattereri under hyperestrogenic and hyperandrogenic conditions, eight days after daily hormonal administration as well as after a 15-day recovery period. Animals were injected subcutaneously with 17β-estradiol, testosterone cypionate or the carrier medium (as control). Histological analysis was used to examine the effect of the treatments. The results show that sex hormones altered the pigmentation of hepatic melanomacrophages and testicular melanocytes. Both liver melanomacrophages and testicular melanocytes in E. nattereri males displayed increased pigmentation after testosterone treatment, while estradiol decreased liver pigmentation only. This study describes, for the first time, the effects of sex hormones on visceral pigmentation of anura, showing the responsiveness of melanocytes and melanomacrophages to sex hormones.
Mechanisms of changes to the liver pigmentary component during the annual cycle (activity and hibernation) of Rana esculenta L.J. Anat.200185-194.
Regulation of the hypothalamic melanin-concentrating hormone neurons by sex steroids in the goldfish: possible role in the modulation of luteinizing hormone secretion.
Effects of environmental pollution on the liver parenchymal cells and Kupffer-melanomacrophagic cells of the frog Rana esculenta.
Ecotoxicol. Environ. Saf.60259-268.
Responses of melanocytes and melanomacrophages of Eupemphix nattereri (Anura: Leiuperidae) to Nle4, D-Phe7-α-melanocyte stimulating hormone and LPS.
The effect of sex steroids on primary and secondary sex differentiation in the sexually dichromatic reedfrog (Hyperolius argus: Hyperolidae) from the Arabuko Sokoke Forest of Kenya.
Gen. Comp. Endocrin.115188-199.
Diethylstilbestrol enhances melanogenesis via cAMP-PKA-mediating up-regulation of tyrosinase and MITF in mouse B16 melanoma cells.
Phylogenetic signal and variation of visceral pigmentation in eight anuran families.
Human melanocytes as a target tissue for hormones: in vitro studies with 1 alpha-25, dihydroxyvitamin D3, alpha-melanocyte stimulating hormone, and betaestradiol.
J. Investig. Dermatol.91593-598.