In present work, low dose 0.0002 g salt/0.02 ml of cadmium chloride (Figure 8) in Larus argentatus illustrated slight alterations in the architecture of the tubules of the
loop of henle. The ultra structure of kidney of Pekin ducks exposed to Cd and degenerative changes in proximal tubules were found [28].
Loop diuretics inhibit sodium, chloride and potassium channels in the
loop of Henle and result in reduced reabsorption of fluid and sodium back into the body.
Chlorothiazide is a sulfonamide loop diuretic that acts on the distal tubule and thick ascending limb of the
loop of Henle. The mechanism of action increases the excretion of sodium, water, chloride, magnesium, potassium, and bicarbonate, thereby promoting diuresis (Skidmore-Roth, 2008).
A number of these diuretics are known as loop diuretics because they function at the level of the
loop of Henle mentioned above.
If membranes of the PCT and descending
loop of Henle reabsorb 80% of the urine filtrate, at "gushing" rates of 80 mL to 120 mL per minute, why are neighboring ascending loop membranes almost impermeable to water?
A: Loop diuretics work by inhibiting sodium reabsorption in the nephron at the
loop of Henle. Despite the usual efficacy of loop diuretics, diuretic resistance can be observed in clinical scenarios such as congestive heart failure (CHF), chronic kidney disease (CKD) and cirrhosis of the liver.
Pathologicaly the primary defect is impairment in one of the transporters involved in sodium chloride reabsorption in the thick ascending limb of
loop of Henle or distal convoluted tubule viz, Na-K-2Cl cotransporter (NKCC2) or apical K channel (ROMK) or basolateral chloride channel (ClCNKB).6 Defect in these channels leads to impaired absorption of Na+, K+, Cl- and calcium in thick ascending
loop of Henle.
Insulin has been related to magnesium reabsorption at the thick ascending
loop of Henle. Insulin deficiency or resistance can promote magnesium wasting at this nephron segment.(8,15) Insulin seems to be one of the most important factors that regulate plasma and intracellular magnesium concentration.
Establishment of this zone is dependent on the orchestrated movement of water and electrolytes from the filtrate as it travels through the
loop of Henle, and on adequate blood flow through the renal capillaries.
Thiazide diuretics work in the distal tubule of the kidneys as well as in the diluting segment of the ascending
loop of Henle. In the distal tubules, they increase the excretion of sodium and chloride by inhibiting the ion pumps that function in sodium and chloride reabsorption.
