Previously, we have compared growth plates treated with HGH to growth plates in response to lateral synovial joint loading. Growth hormone increased the proliferating zone and the hypertrophic zone. Epiphyseal distraction increased all zones including the hyaline cartilage growth plate line. Under LSJL the cell count in all layers remained the same despite the same rate of growth indicating that new stem cells had to be coming in to make up for the stem cells going out and ossifying into bone.
Here's a study(Continuous infusion of insulin-like growth factor-I into the epiphysis of the tibia) that shows a growth plate under treatment with IGF-1.
Right click and click on view image or save as to view the whole picture(or look at the study). You can see how much thicker the discs of the hypertrophic zone are. Confirming that IGF-1 does increase maximal chondrocyte cell hypertrophy. Now, this study was not a longitudinal one so we don't know how much of the increase in growth rate translated into an increase in height but the increase in peak chondrocyte hypertrophy should've resulted in a peak height increase.