Role of prolactin and the gonads in seasonal physiological changes in the collared lemming ( Dicrostonyx groenlandicus)

• Published in: Journal of Experimental Zoology
• Main Authors: Gower, Barbara A., Nagy, Tim R., Stetson, Milton H.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1993
• Subjects: Dicrostonyx groenlandicus
• Online Access: http://dx.doi.org/10.1002/jez.1402660203; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjez.1402660203; https://onlinelibrary.wiley.com/doi/pdf/10.1002/jez.1402660203

Abstract On a seasonal basis, collared lemmings undergo a number of physiological and morphological changes. Short photoperiod exposure results in a molt to a white pelage, an increase in body weight, a reduction in relative body fat content, an increase in relative water content, and the development of a bifid claw. Treatment with the dopamine agonist, CB‐154, resulted in a reduction in serum prolactin and the development of the white pelage in lemmings housed under 16L:8D, while treatment with the dopamine antagonist, sulpiride, prevented the winter molt in animals transferred to 8L:16D. Castration under 16L:8D resulted in an increase in body weight and an enlargement of the bifid claw. Castrated animals also molted more readily when treated with CB‐154 and developed a relatively greater carcass water content. Treatment with CB‐154 increased relative carcass fat content. These findings suggest that, in the collared lemming, seasonal changes in pelage parameters are regulated by prolactin, with gonadal hormones playing a modulating role. Body weight, water content, and bifid claw size appear to be influenced by gonadal hormones. © 1993 Wiley‐Liss, Inc.