Table 1.

Melatonin levels in pg/ml in dispersed pineal cells cultured continuously with medium containing 1 or 10 μM of NE or without NE

Culture	n	5 days	n	7 days	n	9 days
Conditions
Without NE	18	33.4  ± 8.1	18	131.1  ± 32.6	15	317.8  ± 82.3
1 μM NE	16	52.2  ± 6.1	15	45.4  ± 8.1	14	38.6  ± 7.2
10 μM NE	15	49.4  ± 5.7	15	61.5  ± 10.6	16	53.4  ± 12.3

Melatonin levels were measured at the end of a 6-h period of stimulation with fresh medium containing 10 μM of NE in the dark. Melatonin levels were significantly higher in cultures without NE at 7 and 9 days (t test, P < 0.05), but not at 5 days (n, number of cultures tested).