Skin biopsies were taken from female dogs, the primary hair follicles isolated and the dermal papilla dissected. After incubation in supplemented Amniomax complete C100 medium in 24-well culture plates, the dermal papilla cells (DPC) grew to confluence within 3 weeks. Thereafter, they were subcultivated every 7 days. Dermal fibroblast (DFB) cultures were established by explant culture of interfollicular dermis in serum-free medium, where they reached confluence in 10 days. They were subcultivated every 5 days. For immunohistochemistry, cells were grown on cover slips for 24 h, fixed and stained with antibodies against collagen IV and laminin. DPC showed an aggregative growth pattern and formation of pseudopapillae. Intensive staining for collagen IV and laminin could be observed until the sixth passage. DFB grew as branching, parallel lines and showed only weak staining for collagen IV and laminin.

The metabolism of radioactive dehydroepiandrosterone (DHEA) and testosterone was studied in dermal papilla cells (DPC) and dermal fibroblasts (DFB) derived from hair follicles from two different body sites (head, flank) of four male, castrated beagle dogs. Thin layer chromatography was used for separation, and autoradiography for identification of the radioactive metabolites. DHEA was metabolized mainly to 11 alpha-OH-testosterone and only to a minor extent to 11 alpha-OH-androstenedione and another unidentified metabolite. The highest percentage of metabolization of DHEA was found in DFB of the head. Testosterone was metabolized only to a minor extent (less than 10%) to 5 alpha-dihydrotestosterone and epiandrosterone and there was no significant difference between either the two cell types or the two locations. These results clearly show that the metabolization of androgens in canine DPC and DFB is different from that observed in cells from the human hair follicle.

Dermal papilla cells (DPC) and dermal fibroblasts (DFB) derived from hair follicles from two different body sites (head, flank) of four male, castrated beagle dogs were incubated for 24 h with radioactive progesterone (P4). Thin-layer chromatography was used for separation and autoradiography for identification of the radioactive metabolites. In DFB the main metabolites were cortisol and 4-pregnene-11beta-ol-3,20-dione, whereas in DPC they were 5alpha-pregnane-3,20-dione and cortisol. The highest percentage of metabolism of P4 was found in DFB of the head. Smaller amounts of other metabolites were found in both cell types of both locations.

Skin biopsies were taken from four body sites (head, thorax, flank and perineum) of three male entire Beagles and the primary hair follicles were isolated. Culture conditions were established to keep the hair follicles growing for up to 7 days. Additionally, hair follicles were incubated in supplemented medium (containing insulin, transferrin, glutamine and sodium selenite) with or without the addition of testosterone (T) (1, 10 or 100 ng/ml) or oestradiol-17beta (E2beta) (0.01, 0.1 or 1 ng/ml), respectively and the daily growth of hair follicles was measured. In vitro daily growth of hair follicles from the thorax was stimulated by the low concentration of both hormones, but the growth of those from the flank was inhibited by the high concentration of both hormones. Hair follicles from the head were positively influenced by the lowest concentration of T and the medium concentration of E2beta. The daily growth of hair follicles from the perineum was not significantly influenced by either hormone.

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