Choice of lard, but not total lard calories, damps adrenocorticotropin responses to restraint.
Although rats given the choice of eating high-density calories as concentrated sucrose solutions or lard exhibit reduced responsivity in the hypothalamo-pituitary-adrenal axis, rats fed high-fat diets have normal or augmented responses to stressors. To resolve this apparent discrepancy, we compared in adult male rats the effects of 7-d feeding with lard + chow (choice) to feeding a 50% lard-chow mixture (no-choice) and to chow only. Rats with choice composed diets with 50-60% total calories from lard. Rats were exposed to 30 min of restraint on d 7. In the choice group, there was a robust inhibition of ACTH and corticosterone responses to restraint compared with chow or no-choice groups. Total caloric intake was less with choice than no-choice. Fat depot weights and body weight gain were similar in the high-fat groups. Leptin concentrations were equal but insulin was higher in the choice group. We conclude the following: 1) choice of eating high-density calories strongly damps hypothalamo-pituitary-adrenal responses to stress; without choice, high-density diet is ineffective; and 2) insulin may signal metabolic well-being, and may act through hypothalamic sites to reduce caloric intake but through forebrain sites to damp stress responses.
la Fleur
Susanne E
SE
Department of Physiology, University of California San Francisco, San Francisco, California 94143-0444, USA.
Houshyar
Hani
H
Roy
Monica
M
Dallman
Mary F
MF
D000311:Adrenal Glands / Q000503:physiopathology; D000324:Adrenocorticotropic Hormone / Q000502:physiology*; D000818:Animals; D003345:Corticosterone / Q000502:physiology; D004032:Diet; D004041:Dietary Fats / Q000008:administration & dosage*; D019422:Dietary Sucrose / Q000008:administration & dosage; D002149:Energy Intake; D007031:Hypothalamus / Q000503:physiopathology; D007700:Kinetics; D008297:Male; D010902:Pituitary Gland / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012149:Restraint, Physical; D012996:Solutions; D013312:Stress, Physiological / Q000503:physiopathology
D004041:Dietary Fats; D019422:Dietary Sucrose; D012996:Solutions; D000324:Adrenocorticotropic Hormone; C029310:lard; D003345:Corticosterone