JNK phosphorylation is involved in the proliferative and antiapoptotic affects of GH. A) Neurospheres were deposited for 48 h in slides with defined media without EGF and FGF2, and then treated with GH for 1 h. Phospho JNK and GAPDH immunoreactivities were determined by western blot. B) Densitometric evaluation of results presented in A. Phospho JNK levels are expressed as arbitrary densitometric units and normalized to GAPDH levels. C) Neurospheres growing in defined media were treated for 24 h with GH (500 ng/mL), SP600125 (20 μM) or SP600125 + GH. Control cells were treated with saline. Four hours before the end of the treatment period cells were given a BrdU pulse (10 μM). Neurospheres were then dissociated and cells were collected by centrifugation onto coated cover slips, and BrdU was detected by immunocytochemistry. * = p <0.05 vs Control; ** = p <0.001 vs Control and GH. D) Neurospheres were placed into culture plates containing defined media without EGF and FGF2, and 24 h later treated with GH, SP600125 or SP600125 + GH, for an additional 48 h period. Basal apoptosis was determined by growing the cells in the defined media (Control + EGF + FGF2). Apoptosis values in this group were significantly lower (p <0.01) than in the other groups. * = p <0.05 vs Control; ** = p <0.001 vs Control and GH. E = EGF; F = FGF2. Bars= mean + SEM of 3 experiments in triplicate.