Table 1.

GH-mediated changes in GPDH activity

Additions	Fold increase in GPDH activity
None	(1)
GH (25 nM) alone	86  ±  8
GH + cilostimide (10 μM)	82  ±  7
GH + rolipram (10 μM)	162  ±  6
GH + IBMX (500 μM)	181  ±  22
GH + forskolin (10 nM)	165  ±  18
Cilostimide alone	1.5  ±  0.6
Rolipram alone	13.7  ±  8
IBMX alone	13  ±  5
Forskolin alone	9.8  ±  5
GH + DOTAP	84  ±  5
GH + “scrambled” PDE4A5 (10 μM)	85  ±  7
GH + “antisense” PDE4A5 (10 μM)	147  ±  10

Increased GPDH activity has been shown to serve as a marker for differentiation to adipocytes of the F442A cell line. GPDH activity in undifferentiated cells was 3.7 ± 0.2 nanokatals/mg of DNA. The data here show the change in cellular GPDH activity following treatment with 25 nM GH for 30 min. Data are means ± SD for n = 3 separate experiments. The changes in GPDH activity also reflected visual alterations in cell morphology (data not shown).