PMID- 14600347
OWN - NLM
STAT- MEDLINE
DCOM- 20040106
LR  - 20190605
IS  - 0916-7250 (Print)
IS  - 0916-7250 (Linking)
VI  - 65
IP  - 10
DP  - 2003 Oct
TI  - Spermatogenesis, serum testosterone levels and immunolocalization of 
      steroidogenic enzymes in the wild male Japanese black bear (Ursus thibetanus 
      japonicus).
PG  - 1093-9
AB  - Twenty-one wild male Japanese black bears (Ursus thibetanus japonicus) were 
      captured in the summer-autumn of 1998-2000 in the vicinity of Neo Village, Gifu 
      Prefecture. Testes were measured, and testicular samples were biopsied and 
      observed histologically. Four steroidogenic enzymes, i.e., cholesterol side-chain 
      cleavage cytochrome P450 (P450scc), 3beta-hydroxysteroid dehydrogenase 
      (3betaHSD), 17-alpha hydroxylase cytochrome P450 (P450c17), and aromatase 
      cytochrome P450 (P450arom) were immunolocalized. Serum testosterone 
      concentrations were measured by radioimmunoassay. Testis size changed little from 
      1-3 years of age, increased rapidly at 4 years, and attained its peak at 5 years. 
      Serum testosterone concentrations ranged from 0.05 to 1.78 ng/m l, and the mean 
      +/- standard deviation was 0.43 +/- 0.48 ng/ml. Age of sexual maturation in wild 
      male Japanese black bears was estimated to be 3-4 years. Seasonal changes in 
      spermatogenesis were obvious; active in June, July and August, degenerated by 
      September. Leydig cells, Sertoli cells and germ cells have the capability of 
      synthesizing androgen, and Leydig cells, Sertoli cells, spermatids and 
      spermatogonia have the capability of synthesizing estrogen in Japanese black 
      bears.
FAU - Okano, Tsukasa
AU  - Okano T
AD  - United Graduate School of Veterinary Medicine, Gifu University.
FAU - Murase, Tetsuma
AU  - Murase T
FAU - Tsubota, Toshio
AU  - Tsubota T
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Japan
TA  - J Vet Med Sci
JT  - The Journal of veterinary medical science
JID - 9105360
RN  - 3XMK78S47O (Testosterone)
RN  - EC 1.1.- (3-Hydroxysteroid Dehydrogenases)
RN  - EC 1.14.14.1 (Aromatase)
RN  - EC 1.14.14.19 (Steroid 17-alpha-Hydroxylase)
RN  - EC 1.14.15.6 (Cholesterol Side-Chain Cleavage Enzyme)
SB  - IM
MH  - 3-Hydroxysteroid Dehydrogenases/metabolism
MH  - Aging
MH  - Animals
MH  - Animals, Wild
MH  - Aromatase/metabolism
MH  - Cholesterol Side-Chain Cleavage Enzyme/metabolism
MH  - Male
MH  - Seminiferous Tubules/cytology
MH  - Sexual Maturation
MH  - Spermatocytes/cytology
MH  - Spermatogenesis/*physiology
MH  - Spermatogonia/cytology
MH  - Steroid 17-alpha-Hydroxylase/metabolism
MH  - Testis/enzymology/physiology
MH  - Testosterone/*blood
MH  - Ursidae/*physiology
EDAT- 2003/11/06 05:00
MHDA- 2004/01/07 05:00
CRDT- 2003/11/06 05:00
PHST- 2003/11/06 05:00 [pubmed]
PHST- 2004/01/07 05:00 [medline]
PHST- 2003/11/06 05:00 [entrez]
AID - 10.1292/jvms.65.1093 [doi]
PST - ppublish
SO  - J Vet Med Sci. 2003 Oct;65(10):1093-9. doi: 10.1292/jvms.65.1093.