Table 1.

Comparison of the potency and efficacy of pyridine substituted NAADP derivatives between sea urchin egg homogenate and SKBR3 cells.

	Sea urchina		Human SKBR3 cells
Nicotinic acid substituent on NAADP	Fold increase in EC50 compared to NAADP	Agonist efficacy	Fold increase in [cmpd]optimum vs. [NAADP]optimum	Agonist efficacy
5-Amino	1.5	Full	1	Partial
5-Methyl	2.3	Full	100	Partial
5-Thiomethyl	5.0b	Partialb	1	Weak-partial
4-Methyl	2,200.	Partial	1	Partial

^aDerived from Jain et al. [28].

^bUnpublished observations