Inhibition of Prolactin Promotes Secondary Skin Follicle Activation in Cashmere Goats

The study aimed to explore the effect of prolactin (PRL) inhibition on the development of secondary skin follicles in cashmere goats. Goats were divided into a group treated with bromocriptine, a PRL inhibitor, and a control group. After one month, the study found that while the treatment did not significantly affect the length, growth rate, or diameter of cashmere fibers, it did increase the percentage of active secondary follicles in the anagen phase (P < 0.05). The treatment also reduced circulating levels of PRL and IGF1 and increased melatonin levels (P < 0.05). Additionally, bromocriptine treatment decreased mRNA expressions of PRL and MT membrane receptor 1a (MTNR1a) and increased mRNA expression of MT nuclear receptor (RORα) (P < 0.05), without affecting other related receptors and hormones. The conclusion was that PRL inhibition through bromocriptine promotes the activation of secondary hair follicles during the anagen phase, likely through changes in gene expression related to melatonin signaling.