Weight, corticosterone and glucose: changes with time of day after food deprivation.
The effects of constant food deprivation, terminated at different times of day were examined with respect to percent body weight loss (%BWL), plasma corticosterone (PC) and plasma glucose (PG). A 19-hour food deprivation paradigm schedule staggered around varying times of the day-night cycle was used. Patterns of %BWL related to nocturnal lipogenesis and diurnal lipolysis showed the greatest loss (10%) occurring at 0700 hr, while in evening hours, there was an increasing pattern of weight loss, with the greatest amount (7%) occurring at 2200 hr. A pattern suggestive of neuroregulatory cycles of glucocorticoid release was evident for PC levels; maximum levels for PC (23.2 micrograms%) were reported at 0700 hr and at 1900 hr (16.6 micrograms%). Similar patterns were also noted in PG levels, with respective maximum levels of 138.0 mg% and 125.8 mg% occurring at 0700 hr and 1900 hr. These results indicate that the time of day that a deprivation schedule is initiated and terminated is an important consideration due to the impact of circadian photoperiodism. Time of day should be an essential consideration when utilizing deprivation paradigms.
Sommerville
S
S
Department of Psychology, Texas Tech University, Lubbock 79409.
Perez
V J
VJ
Elias
J W
JW
Smith
C J
CJ
D000818:Animals; D001143:Arousal / Q000502:physiology; D001786:Blood Glucose / Q000378:metabolism*; D001835:Body Weight; D002940:Circadian Rhythm; D003345:Corticosterone / Q000097:blood*; D005508:Food Deprivation / Q000502:physiology*; D008053:Lipid Mobilization; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009042:Motivation / Q000502:physiology*
D001786:Blood Glucose; D003345:Corticosterone