Forty mouse strain survey of voluntary calcium intake, blood calcium, and bone mineral content

Alarcón

Lawler

2008

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TORDOFF, M.G., L.K. ALARCON AND M.P. LAWLER. Preferences of 14 rat strains for 17 taste compounds. PHYSIOL BEHAV 00(0) 000-000, 2008.--Two-bottle choice tests were used to assess the taste preferences of 8 male and 8 female rats from 3 outbred strains (SD, LE, WI) and 11 inbred strains (BN, BUF, COP, DA, Dahl-S, F344, FHH, LEW, Noble, PVG, SHR). Each rat received a series of 109 48-h tests with a choice between water and a "taste solution". Four to eight concentrations of the following compounds were tested: NaCl, CaCl 2 , NH 4 Cl, KCl, MgCl 2 , saccharin, sucrose, ethanol, HCl, citric acid, quinine hydrochloride (QHCl), caffeine, denatonium, monosodium glutamate (MSG), Polycose, corn oil, and capsaicin. Strain differences (p<0.001) were observed in preferences for at least one concentration of all compounds tested except denatonium (p = 0.0015). There were also strain differences in the following ancillary measures: fungiform papillae number, water intake, food intake, and body weight. There were sex differences in food intake and body weight but no concerted sex differences in any of the other measures, including preferences for any taste solution. This comprehensive source of information can be used to guide the choice of appropriate rat strains and taste solution concentrations for future genetic studies. Keywordssweet; sour; salty; bitter; umami; calcium; oil; trigeminal; strain survey Rats have been used in many experiments to understand the mechanisms underlying the selection of nutrients and taste compounds. The large majority of these studies have been focused on physiological and behavioral controls of ingestion but rarely on genetic ones. The genetic approach has been spearheaded by work in mice, and has led to several recent important advances, such as the identification of sweet, sour, bitter and umami receptors [reviews (4,10,76)]. One reason for this is that genetic and molecular tools are available for the mouse but not well-developed for the rat, although this is changing [e.g., (2,54,55,62,74)]. Another is that there are few appropriate taste phenotype data available for the rat. Genetic analyses in mice generally begin with the discovery of phenotypic differences among inbred strains but most studies aimed at understanding rat taste preferences have used outbred strains. There are a few comparisons of different rat strain preferences for sodium and ethanol (see below) but very limited data involving other taste compounds.The purpose of this study was to provide comprehensive information about the taste preferences of rats that could be used as the basis for subsequent genetic analyses. To this end, we used Address for all correspondence: Michael G. Tordoff, Monell Chemical Senses Center, 3500 Market St, Philadelphia, PA 19104, Phone: (267)-519-4805, Fax: (267)-519-4738, e-mail: tordoff@monell.org. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscri...

Section: Discussionmentioning

confidence: 78%

Section: Nacl (mentioning

confidence: 99%

Preferences of 14 rat strains for 17 taste compounds

Alarcón

Lawler

2008

Self Cite

“…No 100000; [9]]. After 6-10 days to habituate to laboratory conditions, all the mice received a series of 13 48-h two-bottle preference tests as part of other experiments [see [31,33]]. They also had a 40-µl sample of blood collected after excision of the tip of the tail [all procedures are described in detail elsewhere [30]].…”

Section: Introductionmentioning

confidence: 99%

Forty mouse strain survey of body composition

Reed

Bachmanov

2007

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107

We measured body weight and composition of ~10 male and ~10 female mice from 40 inbred strains. Body composition was assessed in ~16-wk old mice that had been individually housed and fed a high-carbohydrate, low-fat diet (AIN-76A) for the previous 8 wk. Carcass lean and fat weights were assessed using a PIXIMus II DEXA and confirmed by fat extraction assay. There was a nearly continuous range of body weights, from a strain mean±SE of 11.4±0.2 g (MSM/MsJ) to 39.3±1.8 g (NON/LtJ). The percentage of body weight that was fat (%Fat) ranged from 16±4% (C58/J) to 39 ±2% (NON/LtJ). In general, heavier strains had a higher %Fat (r=0.57) but several light strains were also quite fat (e.g., SPRET/EiJ, body weight= 15.7±0.6 g, %Fat=26±1%). Males were significantly heavier than females in 26 strains and significantly fatter than females in 9 strains; only the KK/H1J strain had fatter females than males. Some of the fattest strains are infrequently used in obesity experiments, for example the JF1/Ms and CBA/J strains. These data illustrate the diversity of body weight and composition in inbred mice. They will serve as a reference standard and assist in the selection of strains for future work. KeywordsBody weight; Strain survey; Sex differences; Carcass composition Identifying the genes and alleles underlying body size has posed a challenge. There are many genes involved [22,23] and the effect size of each is usually small [e.g., [15]]. Comparison of inbred mouse strains makes genetic effects obvious because mice within an inbred strain vary much less than do mice between strains [e.g., [13]]. Therefore, a detailed understanding of the variation within and between multiple strains is crucial to help identify alleles that contribute to body size and composition.Several mouse strain surveys of body weight have been conducted [e.g., [1,13,15,35]] and some have also included measures of lean body mass or lipid content [e.g., [13]]. However, these studies have generally been limited to a subset of common laboratory mouse strains and thus do not capture the genetic diversity of currently available strains. Body weight records of 20 inbred strain colonies at the Jackson Laboratory are available [27] but these are not ideal because measurements were made at different times from different colonies, with different husbandry, and there is no information about body composition, i.e., fat and lean weight.The need for a comprehensive survey of body weight and composition has been recognized and is part of a larger effort to study a variety of mouse traits using a large, standard set of inbred strains [Mouse Phenome Project,[28]]. Forty strains have been selected for intensive study based on their frequency of use, genetic variety, and some practical considerations (i.e., cost and ease of breeding). Strain survey data for many traits are available electronically, and several strain surveys for body weight and composition are underway, although they are focused on disease, e.g., a high-cholesterol diet and atherosclerosis [17]. The c...

“…The second strain screen involved 10 males and 10 females of 40 strains [62,92,93]. The 40 strains form the core of the Mouse Phenome Project (MPD), which is an ambitious attempt to populate a database with phenotype information about inbred strains.…”

Section: Choosing the Micementioning

confidence: 99%

“…1; more complete descriptions are available elsewhere [89,92]. The PWK strain had the highest preference scores for all three concentrations of CaCl 2 and CaLa tested.…”

Section: Choosing the Micementioning

confidence: 99%

Gene discovery and the genetic basis of calcium consumption

2008

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This review makes the case that gene discovery is a worthwhile approach to the study of ingestive behavior in general and to calcium appetite in particular. A description of the methods used to discover genes is provided for non-geneticists. Areas covered include the characterization of an appropriate phenotype, the choice of suitable mouse strains, the generation of a hybrid cross, interval mapping, congenic strain production, and candidate gene analysis. The approach is illustrated with an example involving mice of the C57BL/6J and PWK/PhJ strains, which differ in avidity for calcium solutions. The variation between the strains can be attributed to at least seven quantitative trait loci (QTLs). One of these QTLs is most likely accounted for by Tas1r3, which is a gene involved in the detection of sweet and umami tastes. The discovery of a novel function for a gene with no previously known role in calcium consumption illustrates the power of gene discovery methods to uncover novel mechanisms.