QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Harris, R. B. S. Articles by Hervey, G. R. Search for Related Content PubMed PubMed Citation Articles by Harris, R. B. S. Articles by Hervey, G. R.

Voluntary Food Intake of Lean and Obese Zucker Rats in Relation to Dietary Energy and Nitrogen Content¹

Department of Physiology, University of Leeds, Leeds LS2 9JT, England

Genetically obese (fa/fa) Zucker rats maintain a normal lean body size but deposit excessive amounts of body fat. Preferential use of substrates for lipid synthesis results in inefficient use of dietary nitrogen for protein deposition. Three studies were carried out to determine whether an increased protein requirement caused hyperphagia and whether young Zucker rats preferentially regulated protein or energy intake. Rats were offered isoenergetic diets with nitrogen contents ranging from 4.5 to 53.2 mg/g, or isonitrogenous diets with energy contents of 2.2, 3.3 or 4.2 kcal/g. In both situations obese rats had significantly higher food intakes than lean rats. Within phenotype the rats maintained an almost constant energy intake so that nitrogen intake was proportional to dietary nitrogen concentration. In a third experiment lean and obese rats were given different proportions of their control protein intake by stomach tube. Energy intake was determined by voluntary consumption of a protein-free diet. Within phenotype energy intake was the same for all levels of protein intake. It appears that obese Zucker rats regulate energy intake at an elevated level and that protein intake is determined by dietary nitrogen content. Hyperphagia does not appear to result from a desire to obtain protein.

KEY WORDS: • Zucker rats • dietary energy • dietary protein • food intake

¹ This work has previously been presented at a meeting of the Nutrition Society (Proc. Nutr. Soc. 38: 126A, 127A, 1979).

² Ruth Harris held a Science Research Council Studentship.

³ Person to whom reprint requests should be sent, at Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104.

Manuscript received 17 February 1987. Revision accepted 19 November 1987.

This article has been cited by other articles:

				R. B. S. Harris, D. B. Hausman, and T. J. Bartness Compensation for partial lipectomy in mice with genetic alterations of leptin and its receptor subtypes Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2002; 283(5): R1094 - R1103. [Abstract] [Full Text] [PDF]