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K W Cho

Publications and source records attributed to K W Cho.

132 records · Page 8Linked to original sources
PubMed1982

Temperature-induced conversion of the renal adrenoreceptor: modulating renin release.

The release of renin from dog cortical kidney slice preparations incubated in a physiological salt solution can be modulated by alpha- and beta-adrenergic drugs. When given to slices maintained at 37 degrees C, the beta-agonists isoproterenol (ISP) and norepinephrine stimulated renin release from the slices. When the slices were maintained at 20 degrees C, the beta-agonists had no effect on renin release. However, the alpha-agonist phenylephrine inhibited renin release from the slices incubated at 20 degrees C in a dose-dependent manner, whereas its effect on slices incubated at 37 degrees C was less pronounced. The change in response of the slices from beta dominant at 37 degrees C to alpha dominant at 20 degrees C appeared to be a receptor phenomenon. When the cortical slices were incubated with the irreversible alpha-antagonist phenoxybenzamine (POB) at 20 degrees C for 1 h, they were unable to respond to ISP when returned to 37 degrees C. However, POB had no effect on the response of slices to ISP when given at 37 degrees C. It appears that with a decrease in temperature the renal beta-receptors demonstrate properties normally associated with alpha-receptors, namely the potential to be blocked by POB. This may be due to an interconversion of the renal alpha- and beta-adrenoceptors.

Animals↗
PubMed1979

Renin inactivation during in vitro experiments.

Experiments were designed to clarify the factors affecting renin released during in vitro experiments. Kidneys from rat, dog, and pig were used. Experiments were done in which the gas phase was either bubbled through the incubation medium or layered above it. Renin released into the incubation medium disappeared very rapidly when gas was bubbled through the medium. The decline was similar in mediums bubbled with oxygen-CO2 (95%--5%) or nitrogen-CO2 (95%--5%). The half-life of renin activity in the bubbled medium was approximately 15 min in both cases. However, in experiments in which nonbubbled medium was used throughout, renin released into the incubation medium did not disappear after removal of slices. These data are interpreted to mean that the renin released into the incubation medium is inactivated at the air-water interface.

Animals↗
PubMed1978

Renin secretion as a function of renal renin content in dogs.

The in vivo and in vitro rates of renin secretion were measured in kidneys from five groups of dogs in which renal perfusion pressure, salt diet, and neural input were varied to cause large changes in renin secretion rates and renal renin content. It was found that both the in vivo and in vitro secretory rates were proportional to the renal renin content. However, in vitro secretion rates were dependent on content up to 100 ng angiotensin I/mg tissue per h. At higher renin contents no increment in in vitro secretion rate was seen. In vivo secretion rate did not appear to reach a maximum until renal renin content was above 250 ng AI/mg tissue per h. The data are interpreted to support the hypothesis that there exist at least two pools of renin. One releases renin at a fractional rate of about 1.5% of the total content per hour. The other releases renin at a rate dependent on the magnitude of the stimuli acting on the kidneys. It is also suggested that the rate of renin synthesis may be a determinant of the basla rate of renin secretion.

Angiotensin I↗
PubMedDate not supplied

Comparative gene mapping in the domestic cat (Felis catus).

The genetic map of the domestic cat has been developed as a model for studying both feline analogues of human genetic disease and comparative genome organization of mammals. We present here the results of syntenic mapping of 35 genes based upon concordant occurrence of feline gene homologues with feline chromosomes and previously mapped loci in a panel of 41 rodent x cat somatic cell hybrids. These somatic cell hybrids retain rodent chromosomes and segregate feline chromosomes, but in different combinations in each hybrid cell line. Thirty-three of the 35 new locus assignments extend and reaffirm conserved chromosome segment homologies between the human and cat genomes previously recognized by comparative mapping and zoo-FISH. These results demonstrate the extensive syntenic conservation between the human and feline genomes and extend the feline gene map to include 105 assigned loci.

Animals↗