Hormonal Control of Pelage Cycles in the Short-Tailed Weasel (Mustela Erminea Bangsi)

The study investigates the hormonal control of pelage cycles in short-tailed weasels, focusing on the role of the pituitary gland. Hypophysectomized weasels, which had their pituitary gland removed, showed abnormal pelage cycles, regrowing white hair regardless of the season. However, when treated with corticotropin or melanocyte-stimulating hormone, these weasels regrew pigmented hair typical of summer. Treatments with unfractionated ovine gonadotropin resulted in white hair regrowth, while a combination of corticotropin and ovine gonadotropin led to brown hair regrowth. Other hormones like follicle-stimulating hormone, luteinizing hormone, thyroid-stimulating hormone, and hydrocortisone did not affect molting or hair pigmentation. The findings highlight the pituitary gland's crucial role in regulating seasonal pelage changes in weasels.