2. in psychiatry, an unconscious defense mechanism in which unacceptable ideas, fears, and impulses are thrust out or kept out of consciousness. 3. gene r. enzyme repression interference, usually by the endproduct of a pathway, with synthesis of the enzymes of that pathway. gene repression the inhibition of gene transcription of an operon; in prokaryotes repressor binding to the operon is involved.
The ratio of intracellular to extracellular potassium determines neuromuscular and cardiovascular excitability, which is why serum potassium is normally regulated within a narrow range of 3.5 to 5.0 mmol/L. Dietary K+ intake is highly variable, ranging from as low as 40 mmol/day to more than 100 mmol/day.
This ratio must be maintained in order to enable the proper functioning of cell membranes. 2. Potassium is influenced by factors such as insulin and epinephrine, which increase cellular uptake, and high total body potassium levels, which reduce cellular uptake. 3. Within the kidney, aldosterone stimulates the secretion of potassium and the reabsorption of sodium.