Seasonal and daily plasma corticosterone rhythms in American toads, Bufo americanus

Journal Article · Wed Jun 01 00:00:00 EDT 1983 · Gen. Comp. Endocrinol.; (United States)

DOI:https://doi.org/10.1016/0016-6480(83)90271-X· OSTI ID:5578332

Pancak, M K; Taylor, D H

Concentrations of corticosterone were measured in the plasma of American toads, Bufo americanus, on a seasonal basis using a radioimmunoassay technique. Two populations of toads, maintained under different light conditions, were monitored to observe the effects of photoperiod on the seasonal rhythm of plasma corticosterone. Under a natural photoperiod toads demonstrated a rhythm consisting of a spring peak and a fall peak in corticosterone concentration. Toads maintained under a 12L:12D photoperiod all year round demonstrated a similar rhythm with peaks in the spring and fall. This suggests that an endogenous (circannual) rhythm of corticosterone may be playing an important role in the seasonal change of overt behavior and physiology of Bufo americanus. A daily rhythm of corticosterone was also detected in toads when blood samples were taken every 4 hr. When compared to a previously published circadian rhythm study of locomotor activity, the surge in corticosterone concentration for the day occurred at 1730 just prior to the peak in locomotor activity.

• Research Organization: Department of Zoology, Miami University, Oxford, Ohio
• OSTI ID: 5578332
• Journal Information: Gen. Comp. Endocrinol.; (United States), Vol. 50:3
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
CORTICOSTERONE
RADIOIMMUNOASSAY
DAILY VARIATIONS
PHOTOPERIOD
SEASONAL VARIATIONS
TOADS
ADRENAL HORMONES
AMPHIBIANS
ANIMALS
AQUATIC ORGANISMS
CORTICOSTEROIDS
GLUCOCORTICOIDS
HORMONES
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
KETONES
ORGANIC COMPOUNDS
PREGNANES
RADIOASSAY
STEROID HORMONES
STEROIDS
TRACER TECHNIQUES
VARIATIONS
VERTEBRATES
550601* - Medicine- Unsealed Radionuclides in Diagnostics