Table 1.

Biosynthesis of EXC₄ and LTC₄ in human eosinophils

Experiment no.	Arachidonic acid		A23187		Arachidonic acid plus A23187
	EXC4	LTC4	EXC4	LTC4	EXC4	LTC4
1	40	0	0	50	30	14
2	32	0	0	40	16	20
3	58	34	0	198	20	322
4	74	12	0	494	34	420
5	34	20	0	82	26	34
6	12	0	0	108	4	18
7	26	6	0	64	14	16
8	46	10	0	326	18	444
9	16	0	0	170	14	24
10	22	38	0	30	18	36
11	48	22	0	264	12	385

Eosinophils were isolated from 11 healthy donors or patients with hypereosinophilia. The cells were suspended in 1 ml of PBS and incubated with 10 μM arachidonic acid, 1 μM ionophore A23187, or both, for 5 min at 37°C, and the supernatants were thereafter subjected to RP-HPLC analysis. The relative amounts of EXC₄ and LTC₄ were calculated as picomoles per 10⁷ eosinophils.