TABLE 1.

Phosphoinositide levels in 3T3-L6 myoblasts labeled with ³²P or [³H]inositol

Serum concn in cell medium	Lipid	Phosphoinositide levela in cells labeled with 32P or [3H]inositol for the following time:
		32P			[3H]inositol, 48 hb
		1.5 h	3 h	4 h
0.1-1% FCS	PI-3-P	1.004	2.254	1.322	3.203 ± 0.504
	PI-3,4-P2	0.000	0.091	0.288	2.798 ± 0.656
	PI-3,4,5-P3	0.067	0.093	0.166	1.725 ± 0.405
10% FCS	PI-3-P	1.099	1.684	1.266	3.178 ± 0.148
	PI-3,4-P2	0.000	0.019	0.000	0.647 ± 0.241
	PI-3,4,5-P3	0.116	0.083	0.099	0.336 ± 0.098

^a3T3-L6 myoblasts were labeled with ³²P or [³H]inositol for the time indicated in medium supplemented with a low or high concentration of serum, as indicated. Data represent the counts detected in each peak as a percentage of the counts detected in the PI-4,5-P₂ peak.

^bData are shown as means ± standard errors of the means.