Now we'll move along
to the proximal tubule,
and there's a number
of inherited proximal tubular diseases.
The first of these we will discuss
are diseases of glucose reabsorption.
Under normal conditions,
all of the glucose is removed
as it passes
through the proximal tubule,
and this is achieved
due to different apical
and basolateral glucose transporters,
the first of which is the sodium-glucose
transporter type 2,
which is encoded by the SLC5A2;
This is a low affinity,
high capacity transporter
present on the apical side of the cells,
and it's present in the S1 segment.
The second transporter
is the sodium-glucose transporter
which is a high affinity,
low capacity transporter.
It is not only responsible for glucose
and sodium transport
but can also transport galactose,
and this is present in the S3 segment
of the proximal tubule
also on the apical side.
Glucose that's brought
into the proximal tubule
is removed on the basolateral side
which is also a sodium-glucose
and galactose co-transporter,
and it's encoded by the SLC2A2.
Now SGLT2 has recently become a target
to try and alleviate
the symptoms of diabetes
by blocking this protein
and allowing glucose and sodium
to continue the journey
through the rest of the nephron.