ESTP Congress 2003: Case No 6

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Species: Hamster, Syrian Golden
Strain/breeder: Han: AURA (Fraunhofer ITEM Hannover, Germany)
Sex: Male + Female
Age: 8-10 weeks
Study type: Two 3 months studies (A+B), oral
Treatment: Control
Animal status: Scheduled kill
Clinical findings: No clinical findings
Organ(s): Testes, vagina
Gross
finding(s):		 Study A: no findings (slide 6a+6c); study B: diminished in size (slide 6b+6d)
Staining: H&E
Literature:
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Case 6, Fig. 1 (6a)
Fig. 1 (6a) (100k)

Case 6, Fig. 2 (6b)
Fig. 2 (6b) (107k)

Case 6, Fig. 3 (6c)
Fig. 3 (6c) (79k)

Case 6, Fig. 4 (6d)
Fig. 4 (6d) (95k)

Abstract

Influence of light period on male and female reproductive organs in hamsters

A. Heuser, J. Kemkowski, and G. Bode

ALTANA Pharma AG, Institute of Pathology and Toxicology, Hamburg, Germany

Key words: Hamster, light period, reproductive organs

Purpose: To investigate the influence of the duration of light period on reproductive organs in male and female Syrian golden hamsters.

Methods: Two groups of male and female Syrian golden hamster (HAN:AURA) were exposed to a light regimen with either equal light/dark cycles (LD 12/12 hours) or a prolonged light period (LD16/8 hours) for 3 months. Male and female reproductive organs were examined histologically.

Results and Conclusions: In LD 12/12 males, testes showed varying degrees of arrested spermiogenesis. Secretory activity in prostate and seminal vesicles was reduced. Histology of LD 16/8 males indicated normally functioning gonads. In LD16/8 females the vaginal morphology revealed a normal distribution of cyclic stages whereas the majority of LD 12/12 females were in an inactive stage resembling metestrus. In the ovaries of LD 12/12 females, interstitial tissue was increased.

Photoperiod is a critical regulator of reproduction in hamsters. Shortened light periods can induce pseudo-hibernation with regression of male and female gonads. By adjusting light/dark cycle these changes are fully reversible. It is important to be aware of photoperiod induced changes in hamster gonads to avoid misinterpretation as treatment related degenerative or atrophic changes.


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