Related Experiment Video
Updated: Jun 19, 2026
07:38
Induction of Nephrotic Syndrome in Mice by Retrobulbar Injection of Doxorubicin and Prevention of Volume Retention by Sustained Release Aprotinin
Published on: May 6, 2018
THE MECHANISM OF UREA RETENTION IN NEPHRITIS
1Hospital of The Rockefeller Institute for Medical Research.
The Journal of Experimental Medicine
|October 30, 2009
Summary
Urea retention occurs when kidneys resist urea excretion, leading to higher blood urea levels. Ambard
Area of Science:
- Nephrology
- Urology
- Biochemistry
Background:
- Urea retention, characterized by elevated blood urea concentration, signifies increased renal excretion resistance.
- Nitrogenous equilibrium is maintained as increased blood urea overcomes renal resistance.
Purpose of the Study:
- To investigate the applicability of Ambard's laws in urea retention.
- To analyze the behavior of Ambard's constant and identify potential abnormalities in urea excretion.
Main Methods:
- Analysis of urea excretion under varying nitrogen intake and output conditions.
- Application of Ambard's laws to quantify urea excretion dynamics.
- Identification and characterization of 'fixation' in Ambard's constant values.
Main Results:
- Ambard's laws remain valid for urea excretion during retention across diverse conditions.
- While the numerical value of Ambard's constant varies, the interrelationships of factors are preserved.
- A subset of individuals exhibited 'fixation' of Ambard's constant, suggesting potential abnormality.
Conclusions:
- Ambard's laws provide a consistent framework for understanding urea excretion in retention.
- The phenomenon of 'fixation' in Ambard's constant warrants further investigation into its pathological significance.
- Individuals with 'fixation' may represent a distinct group with altered renal urea handling.
Related Concept Videos
01:29Acute Kidney Injury II: Pathophysiology
Acute kidney injury (AKI) causes are categorized into three primary categories based on the location of the injury: prerenal, intrarenal (or intrinsic), and postrenal causes. This classification guides clinical management and illustrates how different pathways can impair kidney function.Etiology and Pathophysiology of Acute Kidney Injury1. Prerenal causesEtiology: Prerenal Acute Kidney Injury, the most common type, occurs when reduced blood flow to the kidneys decreases filtration capacity...
01:20Physiology of the Genitourinary System III: Urine Concentration and Dilution
The kidneys concentrate or dilute urine to maintain water and electrolyte balance. Nephrons, particularly the loop of Henle, play a crucial role in this process through the countercurrent multiplication system. This system establishes a high osmolarity in the renal medulla, which is essential for water reabsorption. In the loop of Henle’s descending limb, water is reabsorbed into the surrounding medulla due to its permeability to water. In contrast, the ascending limb actively transports...
01:23Urea Cycle
The urea cycle describes how liver cells convert ammonia to urea. Ammonia is a toxic waste product of protein catabolism. Land animals must convert ammonia into the less toxic urea which can be safely eliminated by the kidneys through urine. Marine animals excrete ammonia directly, and the surrounding water dilutes the ammonia to safe levels.
01:13Introduction to Urinary System
The urinary system consists of two kidneys, two ureters, the urinary bladder, and the urethra.
The kidneys are bean-shaped organs located in the retroperitoneal space, on either side of the vertebral column, between the T12 and L3 vertebrae. They are partially protected by the rib cage and surrounded by perirenal fat, which provides cushioning. They are responsible for urine formation and play critical roles in regulating blood pressure, electrolyte levels, and hormone production. The ureters...
The kidneys are bean-shaped organs located in the retroperitoneal space, on either side of the vertebral column, between the T12 and L3 vertebrae. They are partially protected by the rib cage and surrounded by perirenal fat, which provides cushioning. They are responsible for urine formation and play critical roles in regulating blood pressure, electrolyte levels, and hormone production. The ureters...
01:10Nephrons
The kidneys are intricate organs with millions of working units known as nephrons. Each nephron features two major structures: the renal corpuscle, which facilitates blood plasma filtration, and the renal tubule, which handles the glomerular filtrate. Blood supply is directly linked to the nephrons. The renal corpuscle consists of the glomerulus, a capillary network, and the Bowman's capsule, a double-walled epithelial structure that encases the glomerulus. The filtering of blood plasma happens...
01:22Physiology of the Genitourinary System II: Tubular Reabsorption and Secretion
The kidneys maintain homeostasis through filtration, reabsorption, and secretion. Tubular reabsorption and secretion are crucial in forming urine and regulating electrolytes, water balance, and waste elimination.Tubular Reabsorption and Secretion ProcessesTubular reabsorption is the process that reclaims essential substances such as electrolytes, glucose, amino acids, and water from the glomerular filtrate back into the bloodstream. This is achieved through passive and active transport...