Mice Lacking the Epidermal Retinol Dehydrogenases SDR16C5 and SDR16C6 Display Accelerated Hair Growth and Enlarged Meibomian Glands

The study presented evidence that two murine epidermal retinol dehydrogenases, SDR16C5 and SDR16C6, are important for retinoic acid biosynthesis in skin and play a role in regulating the hair-follicle cycle and maintaining sebaceous and meibomian glands. Mice lacking both enzymes exhibited accelerated hair growth after shaving and enlarged meibomian glands, along with a nearly 80% reduction in skin retinol dehydrogenase activity. This was associated with up-regulation of hair-follicle stem cell genes, suggesting reduced retinoic acid signaling in the skin of these double-knockout mice. Although the absence of these enzymes did not affect the mice's survival or fertility, their role in skin retinol dehydrogenase activity was deemed essential for normal hair and gland function.