UVA- and UVB-induced changes in hairless mouse skin collagen.

UVA- and UVB-induced alterations in dermal collagen were investigated in a murine animal model. Groups of hairless mice were exposed to UVA and UVB for 28 weeks at a dose of 60 J/cm2 three times weekly and 0.06 J/cm2 three times weekly, respectively. Untreated animals were used as controls. Every 4 weeks dorsal skin was examined for quantitative and qualitative changes in dermal collagen. Neither UVA nor UVB caused a significant alteration in total skin collagen content. However, after UVA treatment the ability of skin collagen to be digested by pepsin decreased dramatically (up to 65% of skin collagen remained insoluble after 4 months), whereas exposure to UVB had no significant effect. Furthermore a shift in the ratio of alpha 1(I,III) chains to alpha 2(I) chains was detected after UVA exposure. The amount of type V collagen in mouse skin, as determined by a sensitive ELISA method, was markedly decreased after UVA treatment, but not after UVB treatment.

Hormone studies in females with androgenic hairloss.

Reports on hormone analysis in androgenic hairloss in the female show partly contradicting results. Elevated as well as normal-range androgen levels have been found. The present study aimed at the investigation of a possibly more differentiated hormonal constellation by hormone analysis and additional determination of the hypophyseal level by the thyrotropin-releasing hormone (TRH) test. In 46 female patients with androgenic hairloss blood sampling for hormone analysis was performed. Determination of the androgens testosterone (T), androstenedione (A), dehydroepiandrosterone sulfate (DHEAS), 17-hydroxy-progesterone acetate (17-OHP) and free testosterone (FT), of sex-hormone-binding globulin (SHBG), estradiol (E2), cortisol (F) and the hypophyseal luteinizing hormone (LH) and follicle-stimulating hormone (FSH) was performed by standard radioimmunoassay methods. The TRH-test is based on feedback mechanisms between the hypothalamic TRH which stimulates hypophyseal TSH and PRL release. Thus, even mild forms of hypothyroidism or hyperprolactinaemia can be detected. The control group for the TRH test consisted of 45 volunteer females without hairloss or any other hormonal or menstrual disturbances. Statistical analysis was performed according to the Wilcoxon two-sample test. The results of the study show no significant elevation of androgens in females with androgenic hairloss, but a more complex condition with involvement of the glandula suprarenalis and the hypophyseal level. Significantly elevated TSH levels prior to and after TRH stimulation in the hairloss group indicate that hypothyroidism may be an important hormonal disturbance in androgenic hairloss. Interactions between hypothyroidism and androgen metabolism are possible at various links.(ABSTRACT TRUNCATED AT 250 WORDS)