DHT and E2 Synthesis-Related Proteins and Receptors Expression in Male Yak Skin During Different Hair Follicle Stages

The study examined the expression of proteins and receptors related to the synthesis of dihydrotestosterone (DHT) and 17ß-estradiol (E2) in male yak skin during different hair follicle stages. It was found that 5α-reductase type 1 (5α-red1) had a higher transcription level than 5α-reductase type 2 (5α-red2) across all stages, with their proteins peaking during anagen and telogen, respectively. Androgen receptor (AR) protein was expressed only during anagen. Aromatase and estrogen receptors (ERα and ERβ) were expressed in epithelial cells, with ERα showing much higher transcription levels than ERβ at each stage. Aromatase protein expression decreased from catagen to telogen, while ERα protein expression increased. The study concluded that 5α-red1 is crucial for DHT synthesis, which promotes hair follicle growth through AR, while E2 may inhibit growth through ERα. These findings provide insight into hormone-regulated hair follicle growth in male yaks, although the number of yaks studied was not specified.