Annual Changes in Serum LH and Testosterone Concentrations in Male Sika Deer (Cervus nippon).

Abstract

Abstract. Although sika deer is valuable for deer farming in Japan, little is understood about the reproductive endocrinology of the male. Especially, there is no information on the blood LH concentration in male sika deer. The present study aimed to determine the annual changes of serum LH and testosterone (T) secretion in male sika deer. Blood samples were collected monthly from three stags for 3 years (1998)(1999)(2000). Serum LH and T concentrations were determined using a secondantibody enzyme immunoassay and a time-resolved fluorescent immunoassay, respectively. The serum LH and T concentrations fluctuated obviously in an annual fashion. The LH concentrations peaked in May, June and July, while the T concentrations peaked in September and October. These results suggest that LH and T secretion in adult male sika deer are mainly controlled by annual rhythm in the same manner as in other temperate cervids. Key words: Sika deer, Stag, LH, Testosterone (J. Reprod. Dev. 48: [613][614][615][616][617] 2002) eer farming is popular in China, New Zealand, A us t r a l ia a nd K o r ea . Var i o us s pec ie s , including red deer (Cervus elaphus), sika deer (C. nippon), rusa deer (C. timorensis) and fallow deer (Dama dama), are farmed to produce venison and/ or antler velvet [1]. In Japan, deer farming has not been as popular. We believe that farming native sika deer would be useful for protecting against genetic contamination of these deer with other species, for providing a constant supply of venison, and for buffering the wild sika deer population that has been reduced by hunting as it has in Europe [2].Successful deer farming requires appropriate management systems based on physiological information. However, such a system for sika deer has not been established yet. Sika deer are seasonal breeders that mate in the fall [3] and it is essential f o r e f f e c t i v e f a r m i n g t o u n d e r s t a n d t h e reproductive endocrinology of this species. Little is known about the reproductive endocrinology of sika deer except for the steroid hormones such as testosterone (T) in males [4][5][6] and progesterone in females [5,7]. Yamaji et al. [8] described seasonal changes in the gonadotropic cells in the pituitary of wild sika deer. However, there is no published information of blood LH concentrations in sika deer. Therefore, this study aimed to determine the annual changes of serum LH and T concentrations in male sika deer.

Immunohistochemical Localization of Steroidogenic Enzymes in the Testis of the Sika Deer (Cervus nippon) During Developmental and Seasonal Changes

“…This result corresponds with a previous report that the diameter of the seminiferous tubules of sika deer testes is significantly increased in the breeding season [2]. These seasonal histological changes of sika deer testes in the breeding season occur simultaneously with the increase in the serum testosterone concentration [10].…”

“…This result corresponds with a previous report that the diameter of the seminiferous tubules of sika deer testes is significantly increased in the breeding season [2]. These seasonal histological changes of sika deer testes in the breeding season occur simultaneously with the increase in the serum testosterone concentration [10].In immunohistochemical examinations, the localization of steroidogenic enzymes in the sika deer has been restricted to the Leydig cells throughout the seasonal changes, whereas the localization of enzymes in the bear [28] and Japanese raccoon dog [25] changed seasonally. In the sika deer, the intensity of immunoreactivity for each steroidogenic enzyme shows seasonal changes like other seasonal breeders, of which the intensity is increased when the testes are fully active [12,44].…”

“…In several seasonal breeders, the serum concentrations of steroid hormones exhibit seasonal fluctuations [7][8][9][10][11][12][13]. In addition, the immunolocalization of steroidogenic enzymes in the testes has been reported to change seasonally in the black bear and northern fur seal [12,13].…”

Immunohistochemcial Localization of Steroidogenic Enzymes in the Testis of Hokkaido Sika Deer (Cervus nippon yesoensis)

“…Consequently the testes used in this study should be representative of the early (early October) and full (late October and November) rutting period. Kameyama et al [12] examined serum testosterone concentration in captured male Hokkaido Sika deer kept at Abashiri (44°01'N, 144°16'E; Northeastern Hokkaido, Japan), and reported that there was a peak of testosterone concentration between September and October, and that it had decreased significantly in November. In the present study the interstitial area occupied by Leydig cells was wider in testes collected in early October than in those from November.…”