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O H Lowry

Publications and source records attributed to O H Lowry.

At least 127 records · Page 7Linked to original sources
PubMed1975

A quantitative histochemical approach to renal transport. I. Aspartate and glutamate.

Renal transport was studied by direct analysis of specific segments of the nephron for the substance transported. Rats were given inulin plus loads of glutamate or aspartate. Glomeruli, six different identified segments, and patches from thin-limb and papillary areas were dissected from individual nephrons in freeze-dried sections. Large amounts of the amino acid (up to 35 mmol/kg) accumulated in segments in which transport is believed to occur. With subthreshold loads, large amino acid increments were confined to earlier proximal segments. With loads above threshold, increases occurred throughout the proximal tubule. The early convoluted tubule probably has less transport activity than the rest of the proximal tubule. Both dicarboxylic amino acids accumulate in large amount when one is given. Aspartate is probably formed within the tubule after a glutamate load. This new histochemical approach may have general applicability for more precise localization of transport cells, for assessing changes in those cells during transport, and for study of structures inaccessible to micropuncture.

Amino Acids↗
PubMed1974

The explanation for the blockade of glycolysis in early mouse embryos.

The reason for the failure of early-stage mouse embryos to grow on glucose alone was investigated by measurement of glucose-6-phosphate, fructose-1,6-bisphosphate plus triose phosphates, citrate, and malate in individual embryos during starvation and refeeding with glucose or glucose plus pyruvate. The results indicate a block at the 6-phosphofructokinase (EC 2.7.1.11) step at early stages, which is later removed. Although there seems to be no early difficulty in phosphorylation of glucose, maximum glucose-6-phosphate levels (and probably fructose-6-phosphate levels) are much lower at early stages than at later stages. The increase in fructose-6-phosphate with age may be the major cause of the increase in 6-phosphofructokinase activity. Unusually high citrate levels at all ages may help to keep this enzyme strongly inhibited until the increase in fructose-6-phosphate occurs. The changes in metabolite levels also indicate an early defect in mobilization of glycogen and a probably less important defect in the citrate cycle.

Animals↗
PubMed1972

The turnover of protein in discrete areas of rat brain.

1. Rats were injected serially with [(14)C]glucose to obtain a constant specific radioactivity of brain amino acids. Measurements with this system for periods of up to 8h gave an apparent mean half-life for protein in whole brain of 85h (indicating the presence of a protein fraction with much more rapid turnover than this). 2. The half-lives of proteins in the granule-cell, molecular and white-matter layers of cerebellum were also determined. These had values of 33, 59 and 136h respectively. In addition, the incorporation into protein in six layers of the cerebral cortex, subjacent white matter and five layers of Ammon's horn was studied. All cell-body layers incorporated amino acids at about the same rate irrespective of location, and these rates were considerably higher than those for incorporation into proteins in areas rich in dendrites or fibre tracts. 3. A new method for measuring small amounts of glutamate with a cyclic enzyme system is presented.

Amino Acids↗