The effect of two isomeric octadecenoic acids on the lipid metabolism and growth of Novikoff hepatoma cells.

The origin and metabolism of octadecenoic acid (18 : 1) was examined in intact Novikoff rat hepatoma cells by using labeled precursors and two isomeric octadecenoic acids which differed in their abilities to stimulate cell growth in a serum-free medium. The isomers (ci-6-18 : 1 and cis-9-18 : 1) were measured in the cellular lipid by ozonolysis and reduction of the ozonides. The results indicate that the 18 : 1 fatty acid accumulated in the cell lipid by uptake of the preformed acid from the medium. The cis-9-18 : 1 to 16 : 1 and 20 : 1 fatty acids by chain shortening and chain elongation. Both isomers inhibited de novo fatty acid synthesis from acetate by cells suspended in a serum-free medium. The isomers did not exert coordinate control of both fatty acid and cholesterol biosynthesis in the Novikoff cells.     

The effect of gender and age on growth hormone replacement in growth hormone-deficient patients.

We analyzed the effect of growth hormone replacement therapy (36 months) analyzed at a dose adjusted to maintain serum insulin-like growth factor-I level between the median and the upper end of the age-related reference range on bone mineral density, body composition, and carbohydrate metabolism with respect to gender and age in 20 adult patients (9 women, 11 men, mean age: 43 years, range: 21-61 years). The lumbar and femoral T-score was increased after 12 and after 18 months of therapy respectively in men (p < 0.001 and p = 0.002), but did not changed significantly in women. The increase of femoral T-score was greater in young men (< or = 45 years, n = 6) than old men (> 45 years, n = 5, p < 0.001). Body fat was lower in men than in women after 6 months (p = 0.002). The waist/hip ratio only decreased in women (p = 0.044). The waist circumference decreased in both genders after 6 months of therapy (p < 0.001), but more markedly in females than in males (p < 0.05). The sum of skinfold thicknesses was reduced in males after 6 months of therapy (p < 0.001). Changes in body composition parameters measured were independent of age. The glycosylated hemoglobin increased without sex or age difference after 12 months of initiation of therapy (p < 0.001), but fasting glucose and insulin levels did not change during the therapy. Our results indicate that the effect of growth hormone replacement on bone mineral content in adults is age- and gender-dependent, gender dependent on body composition, but independent of age and gender on carbohydrate metabolism.     

The effect of aureomycin on the growth and metabolism of the pig

The effect of dietary aureomycin on the growth of the pig has been studied under conditions of full-feeding and equalized feed intake. The growth response to aureomycin appeared to be dependent upon an increased daily feed intake. Such factors as hemoglobin level, efficiency of feed utilization, nitrogen balance, and energy balance did not seem to be influenced by feeding aureomycin under the conditions imposed by this experiment.     

The effect of nitrogen deficiency on the growth and metabolism of Lemna minor L.

When Lemna is deprived of nitrogen, growth and respiration decrease and the pattern of ¹⁴CO₂ release from [1-¹⁴C]glucose and [6-¹⁴C]glucose is consistent with a relatively strong inhibition of glycolysis. Protein degradation is enhanced but the concentration of free amino acid decreases. It is argued that the biological significance of the increased protein degradation does not lie in its contribution to respiration but as a mechanism to replace one set of enzymes adapted to a particular environmental condition (high nitrogen) with another set of enzymes adapted for low nitrogen in the environment. The change in enzyme pattern associated with the change from high to zero nitrogen in the growth medium has been examined for nine enzymes. The changes in activity observed are consistent with the observed apparent inhibition of glycolysis during nitrogen starvation, but do not explain the inhibition of the pentose phosphate pathway.     

The effect of oxytetracycline on growth and lipid metabolism in poultry

The effect of oxytetracycline at doses of 0.291, 0.461, 0.922, 1.383 and 1.844 g/l in drinking water on the growth rate, lipid metabolism, GOT, GPT, calcium and magnesium was studied on one-day-old chicks and laying hens (Gallus domesticus). Oxytetracycline at a dose of 0.461 g/l increased body weight gain in one-day-old chicks. Oxytetracycline had no effect on hepatic triglyceride and phospholipid levels while cholesterol levels were decreased in one-day-old chicks and increased in laying hens. Oxytetracycline tended to decrease serum cholesterol and to increase serum triglyceride concentrations while its effect on serum phospholipids were inconsistent. Oxytetracycline, although inconsistent, tended to increase GPT and GOT activities in both young chicks and laying hens. Higher doses of oxytetracycline resulted in fatty changes in the hepatocytes and cells of the kidney tubules and lungs in both young chicks and laying hens. With the exception of hepatic phospholipids, all other parameters were higher in laying hens than in young chicks.     

The effect of hypophysectomy and growth hormone replacement on albumin synthesis and catabolism in the rat

Albumin synthesis and catabolism were respectively measured by McFarlane's (1963) sodium [(14)C]carbonate method and I-labelled albumin in hypophysectomized rats, both untreated and treated with growth hormone. Hypophysectomy resulted in a decrease in both albumin synthesis and catabolic rates. These changes as shown by pair-feeding experiments could not be ascribed to decreased food intake alone. Growth hormone was shown to partially restore both albumin synthesis and catabolic rates. It is proposed that growth hormone stimulates albumin synthesis and that its effect on albumin catabolism is secondary to changes in the mass of the intravascular albumin pool.     

The effect of amino acids on growth and phosphate metabolism in a prototrophic yeast strain.

The addition of casamino acids to a log. phase culture of a prototrophic yeast strain under conditions in which their catabolism is repressed caused stimulation in growth rate. The neutral amino acids and arginine were the principal contributors to this stimulation effect. An early response of the cells to the addition of amino acids was the accumulation of low molecular weight polyphosphates. This accumulation was shown to correlate to the basicity of a given amino acid rather than to its effect on growth rate. A role for the polyphosphates in intracellular buffering is therefore suggested.     

The effect of pH on the growth and metabolism of Streptococcus bovis in continuous culture

Streptococcus bovis H13/1 was grown anaerobically at pHs between 5.0 and 6.5 in a glucose-limited chemostat at a dilution rate of 0.05/h. The growth yield and the production of acetate, ethanol and formate decreased at pHs less than 6.5 whereas the production of lactate increased at the lower pH values. When a culture was subjected to sequential pH changes, growth yield and fermentation products were influenced not only by the pH existing in the culture medium but also by the metabolic activity of the cells at the preceding pHs in the sequence. The results are discussed in relation to the mechanisms available for the maintenance of pH homeo-stasis and for the metabolic control of fermentation pathways in Strep. bovis.     

The effect of pH on the growth and metabolism of Streptococcus bovis in continuous culture

Streptococcus bovis H13/1 was grown anaerobically at pHs between 5.0 and 6.5 in a glucose-limited chemostat at a dilution rate of 0.05/h. The growth yield and the production of acetate, ethanol and formate decreased at pHs less than 6.5 whereas the production of lactate increased at the lower pH values. When a culture was subjected to sequential pH changes, growth yield and fermentation products were influenced not only by the pH existing in the culture medium but also by the metabolic activity of the cells at the preceding pHs in the sequence. The results are discussed in relation to the mechanisms available for the maintenance of pH homeostasis and for the metabolic control of fermentation pathways in Strep. bovis.