No matter how it is born, a new gene starts its life as a single copy in the population.

As with any new mutation, by far the most likely outcome is that it will be lost by random drift or selection over the next few generations

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#Id: 5784

#Unit 7. System Physiology – Animal

Basolateral membranes of thyrocytes contain a symporter Na+/I –symporter (NIS) 

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#Id: 5785

#Unit 7. System Physiology – Animal

Process of concentrating the iodide in the cell is called iodide trapping

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#Id: 5786

#Unit 7. System Physiology – Animal

Na+/I – symporter (NIS) is capable of producing intracellular I – concentrations that are 20– 40 times as great as the concentration in plasma

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#Id: 5787

#Unit 7. System Physiology – Animal

Wolff –Chaikoff effect large doses of iodide act directly on the thyroid to produce a mild and transient inhibition of organic binding of iodide and hence of hormone synthesis.

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#Id: 5788

#Unit 7. System Physiology – Animal

Thyroid stimulating hormone induces both NIS expression and the retention of NIS in the basolateral membrane.

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#Id: 5789

#Unit 7. System Physiology – Animal

Iodide is transported out of the thyroid cells across the apical membrane into the follicle by a chloride-iodide ion counter- transporter molecule called pendrin.