Thyroid and gonadal regulation of hair growth during the seasonal molt in the male European badger, Meles meles L
February 1987
in “
General and comparative endocrinology
”
thyroxine testosterone thyroidectomy castration thyroxine supplementation testosterone implants hair follicle activity seasonal molt plasma levels of thyroxine photoperiod thyroid hormone testosterone hormone thyroid removal neutering thyroid hormone supplementation testosterone hormone implants hair follicle activity seasonal shedding blood levels of thyroid hormone day length
TLDR Thyroid and gonadal hormones control seasonal hair growth and molting in male European badgers.
The study on male European badgers (Meles meles L) demonstrated that hair growth and seasonal molt were regulated by cycles of plasma testosterone and thyroxine. Various groups of badgers, including controls, thyroidectomized, castrated, and those treated with hormone implants, were studied. It was found that high thyroxine levels (about 20 ng/ml) coincided with the start of molt and maximum hair growth. Castration advanced molt and hair growth, while testosterone implants delayed them. Thyroidectomy prevented hair growth and molt, but these processes resumed with thyroxine supplementation. The study concluded that both thyroid and gonadal axes, influenced by the hypothalamus and pituitary and synchronized by photoperiod, jointly regulated the seasonal molt and hair growth in European badgers.
