The Effects of Various Lighting Schedules upon the Circadian Rhythms of 23 Liver or Brain Enzymes of C57BL/6J Mice

Details

• Personal Author:
  Casciano DA ; Delongchamp RR ; Feuers RJ ; Pauly JE ; Scheving LE ; Tsai T-H
• Description:
  The activities of 23 brain or liver enzymes were studied in 5-6 week old C57BL/6JNctr male and female mice that had been fed ad libitum and standardized for 2 weeks to either (1) 12 hr of light (0600-1800) alternating with 12 hr of darkness (1800-0600) (LD 12:12), (2) staggered sequences of 12 hr of light and 12 hr of dark (SLD 12:12) or (3) continuous illumination (LL 12:12) for 2 weeks. Mice in the LD 12:12 and LL 12:12 experiments were killed at 4 hr intervals along a 24-hr span in order to sample at six different circadian stages. Lighting schedules for mice in the SLD 12:12 experiment were organized such that six different circadian stages were sampled when all mice were killed at one time of day. All 23 enzymes demonstrated a prominent circadian rhythm in at least one of the experiments. Moreover, about two-thirds of the enzymes in LD and SLD 12:12 had a statistically significant fit to a 24-hr cosine curve, while only one-third of the enzymes in LL 12:12 had significant fits to cosine curves. Peak activities of enzymes from mice in LD 12:12 were clustered at the time of transition from light to dark. This was also the trend for the activities of enzymes from mice in SLD 12:12, but resynchronization did not appear completed within the 2-week span. This, along with the observation that mesors (mean 24-hr activity) were reduced and amplitudes altered, indicated that the 2-week standardization period was not sufficient for some enzymes. Times of peak activities, mesors and amplitudes were affected for most enzymes from mice in the LL 12:12 environment. This suggests that individual mice became desynchronized from one another with respect to the original light-dark schedule and that rhythms were altered or lost because individual mice were free running with frequencies different from 24 hr. [Description provided by NIOSH]
• Subjects:
  Animals Circadian Rhythm Enzymes Lighting Occupational Health Safety
• Keywords:
  Animal Studies Biological Rhythms Brain Function Circadian Rhythms Physiological Effects
• ISSN:
  0742-0528
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Arkansas ; OSHA Region 6
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  221-235
• Volume:
  3
• Issue:
  4
• NIOSHTIC Number:
  nn:20060373
• Citation:
  Chronobiol Int 1986 Oct; 3(4):221-235
• Contact Point Address:
  Dr. Ritchie J. Feuers, NCTR/DGT/HFT-120, Jefferson, AR 72079, U.S.A.
• Federal Fiscal Year:
  1987
• Performing Organization:
  University of Arkansas Med Scis Ltl Rock, Little Rock, Arkansas
• Peer Reviewed:
  True
• Start Date:
  19791201
• Source Full Name:
  Chronobiology International
• End Date:
  19880301
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:9a9f40df5236bd573f699240b355b350ffe7fa1031edd360ad3ba9617b538957dbe681fe9a9e7f8bb8c10dbf03651d50a43a01dba00f77133015d5065889d4af
• Download URL:
  https://stacks.cdc.gov/view/cdc/224307/cdc_224307_DS1.pdf
• File Type:
  [PDF - 400.33 KB ]