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M Fiorotto

Publications and source records attributed to M Fiorotto.

8 recordsLinked to original sources
PubMed1997

Lactase phlorizin hydrolase synthesis is decreased in protein-malnourished pigs.

We have examined the effect of protein malnutrition on brush border (BB) lactase phlorizin hydrolase (LPH) synthesis in young pigs. Two groups of four 3-wk-old pigs were fed diets containing either 19 g soy protein, 63 g carbohydrate and 5 g fat per 100 g diet (a protein-sufficient diet) or 3 g soy protein, 85 g carbohydrate and 5 g fat per 100 g diet (a protein-deficient diet). After 8 wk of consuming the diets, pigs were infused intravenously with 2H3-leucine for 8 h, then killed. The jejunum was collected for measurement of lactase activity, LPH mRNA abundance and the rate of LPH post-translational synthesis. Lactase activities did not differ between groups (mean 8.1 +/- 1.2 micromol x min(-1) x g mucosa(-1)). LPH mRNA abundance relative to elongation factor-1alpha mRNA (the constitutive/reference mRNA) was significantly (P < 0.05) higher in well-nourished pigs (0.36 +/- 0.03%) than in protein-malnourished pigs (0.21 +/- 0.02%). The rate constants of BB LPH post-translational synthesis were also significantly higher in the well-nourished (103 +/- 9% x d(-1)) than in the protein-malnourished pigs (66 +/- 8% x d(-1)). Further, the absolute synthesis rate of BB LPH, a measure of the amount of enzyme synthesized per gram of tissue, was significantly higher in well-nourished than in protein-malnourished pigs (in arbitrary units, 892 +/- 90 vs. 450 +/- 34, respectively). Thus, protein malnutrition affects both LPH mRNA abundance and post-translational processing in young pigs.

Animals↗
PubMed1996

Chronic low protein intake reduces tissue protein synthesis in a pig model of protein malnutrition.

To determine the effect of severe chronic protein deficiency on protein synthesis in different tissues and total protein in plasma, and on plasma biochemical constituents involved in amino acid metabolism, we fed diets containing either 20 or 3% protein to two groups of four age-matched piglets. After consuming the diets for 8 wk, the pigs received a primed-constant infusion of 2 H3-leucine for 8 h to measure the fractional synthesis rates (FSR) of tissue protein and total protein in plasma. Plasma urea and amino acid concentrations, particularly indispensable amino acids, were significantly lower in protein-deficient pigs. Fractional protein synthesis rates were lower in skin by 66% (P < 0.01), in jejunal mucosa by 50% (P < 0.05), in masseter muscle by 40% (P < 0.05), and in liver by 25% (P < 0.02); the fractional synthesis rate of the longissimus muscle was not different than controls. Although plasma protein concentration was significantly (P < 0.01) lower in protein-deficient pigs, the fractional synthesis rate of the total intravascular plasma protein pool was not different. We conclude that adaptation to a low protein diet involves a reduction in the rate of protein synthesis in most body tissues, with the most marked changes occurring in skin and intestine, two tissues which frequently exhibit severe functional impairment in protein malnutrition.

Amino Acids↗
PubMed1995

Influence of early feeding mode on body composition of infants.

To determine the effect of infant feeding mode on body composition, a cross-sectional study was designed in which 10 breast-fed and 10 formula-fed infants were studied at 1 month of age, and another 10 breast-fed and 10 formula-fed infants at 4 months of age. Anthropometric measurements included body weights, lengths, selected diameters, circumferences and skinfold thicknesses. Total body water (TBWO) was measured by 18O dilution. A dose equivalent to 300 mg 18O/kg body weight was administered orally to the infants. Fat-free mass (FFMO) was calculated from TBWO using reference hydration constants of 0.805 and 0.798 at 1 and 4 months, respectively. Body fatO was taken as the difference between weight and FFMO. Total-body electrical conductivity (TOBEC) measurements were used to estimate FFMT and FATT. ANOVA was used to analyze the anthropometric and body composition data using feeding mode and age as grouping factors. Anthropometric measurements did not differ by feeding mode. TBW (kg) and FFM (kg) and body fat (kg) derived from 18O dilution or TOBEC did not differ by feeding mode. TBWO,T (%wt), FFMO,T (%wt), and body fatO,T (%wt) derived from 18O dilution and TOBEC differed significantly between the breast-fed and formula-fed infants at 4 months of age (p < 0.05). Expressed as a percentage of body weight, TBWO and FFMO,T were higher and body fatO,T was lower among the 4-month formula-fed infants.

Adipose Tissue↗
PubMed1987

Electrolyte composition changes of chronically K-depleted rats after K loading.

The responses of whole body, skeletal muscle, and plasma to oral K loading were studied in K-depleted male rats. Potassium depletion was induced by feeding the rats a K-deficient diet for 4 wk and injecting deoxycorticosterone acetate during the first week. After 4 wk, the rats were growth retarded and hypokalemic (1.9 mmol/l plasma) and had low whole-body and muscle K content, 188 +/- 27 and 276 +/- 19 mmol/kg fat-free dried tissue (FFDT), respectively, compared with 296 +/- 10 and 454 +/- 13 mmol/kg FFDT for the control group. Sodium and water retention also occurred in the K-deficient group. After K depletion, the rats were divided into four groups and received either 0, 1, 2, or 3 intragastric doses of 10 mmol KCl/kg at 8-h intervals. The rats were killed 8 h after the last dose. Control rats were treated similarly. K-depleted and control rats responded differently to K loading. In the normal rats, plasma K remained at 5.0 +/- 0.5 mmol/l, muscle K increased to 502 +/- 24 mmol/kg, and muscle K/N ratio increased from 3.0 to 3.4 mmol/g. In the K-depleted rats, plasma K increased to 7.2 +/- 0.7 mmol/l, muscle K increased to 453 +/- 50 mmol/kg, and muscle K/N ratio increased from 1.8 to 3.1 mmol/g. These data indicate that the capacity of the muscles to accumulate K was impaired after severe K depletion and caused elevated plasma K levels when repletion was complete.

Animals↗