Luminal and cellular mechanisms for the mediation of tubuloglomerular feedback responses.

The results of our studies indicate that feedback-mediated changes in SFP are most likely the result of receptor cell detection of luminal fluid solute concentration. No specificity for any particular ion in mediating feedback responses could be identified. The detection of luminal fluid solute concentration may involve an intracellular cytoplasmic calcium system. The existence of a receptor cell intracellular calcium messenger system could serve as the link between changes in distal tubular fluid concentration and the alteration in glomerular vascular resistance.