Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Endocrinology. 1988 Jun;122(6):2634-8.

Djungarian hamsters exhibit reproductive responses to changes in daylength at extreme photoperiods.

Author information

  • 1Laboratory of Developmental Chronobiology, Massachusetts General Hospital, Boston 02114.

Abstract

In seasonally breeding species, an animal's photoperiodic history (the daylength or photoperiod previously experienced) influences the reproductive response to new photoperiods. However, this has only been examined over a relatively narrow range of photoperiods. We assessed whether Djungarian hamsters (Phodopus sungorus) respond to daylength changes at extremely long and extremely short photoperiods. To determine the extent and temporal sequence of reproductive responses to photoperiod changes, ultrasonography was employed to determine serial changes in testis weight in individual animals; serial changes in body weight and pelage color were also assessed. Male animals (60-day-old) shifted from 6 h of light/day (6L) to 10L showed partial testicular recrudescence and darkening of the coat. In control animals remaining in 6L, testes remained small, and coat color continued to lighten. Animals shifted from 20L to 16L showed partial and transient testicular regression, whereas testes remained large in control animals remaining in 20L. There were no significant differences in body weight between control and experimental animals in either study. These findings indicate that Djungarian hamsters respond reproductively to changes in photoperiod at extreme daylengths, but the magnitude of the response appears to be dependent on the absolute daylength.

PMID:
3371260
[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Atypon
    Loading ...
    Write to the Help Desk