DECIDUOUS NATURE OF DEER ANTLERS 361 



spermatogenesis the follicles decreased in size, stored less colloid, 

 and exhibited more columnar epithelium. The effects of hvpothyroid- 

 ism have been studied by Wislocki et al. ( 1947 ) , who reported nor- 

 mal antler development subsequent to thyroidectomy of a 2-month- 

 old fawn. Lebedinsky (1939) noted enhanced antler growth in roe 

 bucks which had received thyroxin injections as fawns. In adults 

 of this species, however, Bruhin (1953) was unable to affect antler 

 growth by oral administration of 1 mg thyroxin per day for 1 month 

 during the antler growing period. But in vearling reindeer and 

 fallow deer thyroxin injections induced strikingly greater antler 

 growth than in controls. 



Inasmuch as antler shedding is effected by localized erosion of 

 bone, a phenomenon well known to be under the control of the 

 parathyroid gland, it is surprising that the parathyroids of deer have 

 not been more thoroughly investigated. What we do know, how- 

 ever, does not indicate a direct relationship of this gland to antler 

 shedding. Grafflin (1942) reported the lack of histologically de- 

 tectable annual changes in the parathyroid glands of Virginia deer. 

 Moreover, experiments by the author involving semiweekly injec- 

 tions of 1 gm of powdered ox parathvroid glands into each of 3 

 adult sika bucks for 8 weeks in the autumn failed to bring about any 

 indications of antler shedding. 



There is possible evidence that the adrenal cortical hormones play 

 roles in antler growth. Wislocki ( 1943) stated that the adrenal glands 

 of male Virginia deer exhibit no histological alterations correlated 

 with seasonal changes. More recently, however, Hucin (1957) has 

 described increased secretorv activity in the zona glomerulosa dur- 

 ing the period of antler growth in the red deer ( a correlation between 

 mineral metabolism and mineralocorticoids ) , but only slight changes 

 in the activities of the inner zones associated with the rutting season. 

 It is interesting to note that Doutt and Donaldson (1959) have re- 

 ported the unusual occurrence of a female Virginia deer bearing 

 antlers which might have been attributable to androgens secreted 

 by an adrenal cortical tumor. Cortisone probably does not influence 

 antler development, for Taft et al. (1956) reported that ACTH 

 injections exerted little or no effect on the antlers of Virginia deer. 

 The present author has shown that 8 weekly injections of 500 mg of 



