Renal Tubular Transport #16. S1 Segment, Proximal Tubule. Organic Anion Transport 1

over 4 years ago

Picture Steemit Renal Tubular Transport.jpg

This post is showing the organic anion transport.

The Na/K ATPase, which brings 2 potassium ions into the cell and releases 3 sodium ions into the interstitial space.
The sodium/dicarboxylate cotransporter (NaDC1) at the apical membrane, which brings in 3 sodium ions from the filtrate together with 1 dicarboxylate ion which could be citrate, α keto-glutarate or succinate.
The sodium/dicarboxylate cotransporter (NaDC3) at the basolateral membrane, which brings in 3 sodium ions from the interstitium and brings in mainly α keto-glutarate. This transporter is important for the organic anion transport which will be shown at a later post.
The sodium/monocarboxylate cotransporter (SMTC2) at the apical membrane, which brings in 2 sodium ions from the filtrate together with 1 monocarboxylate ion such as lactate.
In the basolateral membrane, the α keto-glutarate brought in by NaDC3 is exchanged again so than an organic anion can be brought in from the interstitial space.
In the apical membrane, OAT4 and URAT1, bring in urate so that organic anions can be released into the filtrate. OAT4 focuses more in dicarboxylates and URAT1 in monocarboxylates and chlorine.
Organic anions can be metabolites of endogenous or exogenous compounds, with a negative charge.

Picture Steemit Tubular Cell Transport Organic Anion 1.jpg