Glucagon like peptide 1 (GLP-1) is released from enteroendocrine L-cells in the gut epithelium and plays an important role in post-prandial glucose homeostasis and appetite control. Following the successful introduction of GLP-1 mimetics and DPP4 inhibitors to treat type 2 diabetes, attention is now turning towards the L-cell, to address the potential benefit of stimulating the endogenous release of L-cell peptides in vivo. These cells release not only GLP-1 but also the anorexigenic peptides, PYY and oxyntomodulin, as well as GLP-2 which stimulates epithelial regeneration and repair. Understanding the mechanisms underlying secretion from L-cells is key to discovering ways to target the cells therapeutically. In vitro studies on L-cell physiology, previously largely restricted to the use of cell lines, can now be performed on primary intestinal cultures from transgenic mouse lines in which GLP-1 secreting cells are identifiable by their expression of a fluorescent protein. Primary L-cells are electrically active and nutrient responsive. The pattern of action potential firing is determined by tetrodotoxin-sensitive voltage-gated sodium currents. Secretion, by contrast, is dependent on voltage-gated calcium currents which are largely carried by L-type and Q-type calcium channels. Agents that stimulate GLP-1 secretion employ a number of transporter and receptor pathways, including electrogenic nutrient uptake, metabolism and G-protein coupled receptor activation. Targeting these pathways provides potentially novel strategies to increase L-cell secretion in vivo. GPR119 and TGR5 are two Gs coupled receptors that are highly expressed in L-cells. Agonists of both receptor types result in elevated cAMP in L-cells, with downstream effects on membrane potential and hormone secretion. Although the new protocols for studying single primary enteroendocrine cells provide novel avenues for the discovery of L-cell specific drug targets, definitive trials are now required to demonstrate that L-cell stimulation will translate into a clinically useful therapeutic strategy.