Macronutrient intake and utilization by rats: interactions with type I adrenocorticoid receptor stimulation.
Corticosterone-free (adrenalectomized, ADX) and intact rats were offered experimentally compounded diets in which 65% of available calories were supplied by a single macronutrient (single-diet study). ADX impaired the intake, weight gain (especially as body fat), and efficient utilization of high-protein and high-fat diets. In contrast, no behavioral, metabolic, or compositional changes could be found among ADX rats maintained on a diet high in carbohydrates. When ADX rats were given separate sources of macronutrients (self-selection study) they did not self-select a high-carbohydrate diet. Instead, they displayed a strong fat avoidance and a relative increase in protein intake, the macronutrient they utilize least efficiently. Separate groups of ADX animals were continuously infused with 25 or 125 micrograms.kg-1.day-1 aldosterone, a specific type I adrenocorticoid receptor agonist. Type I receptor stimulation eliminated all ADX-related deficiencies found in the single-diet and self-selection studies: caloric intake, feeding efficiency, carcass composition, and macronutrient preferences were restored to or beyond the corresponding values of adrenal-intact rats. The normal rat's ability to ingest and utilize macronutrients optimally is dependent on corticosterone's stimulation of type I receptors.
Devenport
L
L
Department of Psychology, University of Oklahoma, Norman.
Knehans
A
A
Thomas
T
T
Sundstrom
A
A
D000311:Adrenal Glands / Q000378:metabolism / Q000601:surgery / Q000648:ultrastructure; D000315:Adrenalectomy; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000450:Aldosterone / Q000494:pharmacology; D000818:Animals; D004032:Diet; D004040:Dietary Carbohydrates / Q000378:metabolism; D004041:Dietary Fats / Q000378:metabolism; D004044:Dietary Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004734:Energy Metabolism / Q000502:physiology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D018043:Receptors, Corticotropin; D011979:Receptors, Pituitary Hormone / Q000187:drug effects / Q000502:physiology
D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins; D018043:Receptors, Corticotropin; D011979:Receptors, Pituitary Hormone; D000450:Aldosterone; D000324:Adrenocorticotropic Hormone