Nyctohemeral Rhythm in Melatonin Response to Isoproterenol In vitro: Comparison of Rats and Syrian Hamsters
Abstract
The in vitro response of melatonin synthesis was assessed by incubation of individual whole pineal glands for 4 hr without or with different concentrations of isoproterenol in the medium. Pineals were taken either at the end of the 14-hr light phase (day), or at 6.5 hr into the 10-hr dark phase (night) after a 30-min exposure of the animals to light just before sacrifice at night. The response was greater in pineals taken at night than in those taken at the end of the light phase in rats, but was absent at end of the light phase in Syrian hamsters. Hamster pineals taken at night responded, though higher isoproterenol concentrations were required than in the rats. Unresponsiveness of hamster pineals during the day may explain previous failure of isoproterenol administration to stimulate pineal MEL content in this species.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1987
- Accession Number
- ADA187374
Entities
People
- Arthur D. Mason Jr.
- Basil A. Pruitt Jr.
- George M. Vaughan
Organizations
- United States Army Institute of Surgical Research