TGF is an endogenously produced hormone-like substance that plays a role in fat cell apoptosis (cell death). In times of starvation, such as long term carbohydrate depletion, adipose tissue produces TGF as a means of blocking fat cell anabolism, this means insulin in unable to trigger fat cell growth yet still possesses its powerful anabolic signal for muscle.
This in turn facilitates the process of fatty acid mobilization (release from adipocytes/fat cells) and subsequent utilization as an energy source for the body. The result is fat cell starvation and eventual apoptosis. This is synergistic with natural PGF-2 elevation since localized increases in PGF-2 also result in an increase in TGF production. There also appears to be correlation between endogenous /exogenous GH levels and TGF. The higher the GH level, the more TGF produced in/by adipose tissue. This somewhat explains the extreme fat loss that occurs during GH administration even without a change in dietary habits.
Bodybuilders utilized exogenous forms of TGF as a means of fat cell eradication. Picture the number of fat cells in an athlete's body decreased by 20-50 %! During administration, fatty acids provide food for hard training muscle. Post administration, the athletes possessed a much lower potential for gaining fat tissue while creating a superior ability to utilize calories to build muscle. Simply stated, this means less mouths (cells) to feed = more calories for muscular repair and growth. Obviously there was a synergistic chemistry possibility utilized by athletes. TGF alone would be catabolic to lean mass tissue so an increase in the anabolic signal from GH, insulin, PGF-2, and/or IGF-1 was reported to be utilized by the few who had personally experimented with the drug. This was mostly done through TGF use to create an Absolute Anabolic Phase (See "Building The Perfect Beast" featuring "Frank N. Steroid" for more info on Absolute Anabolic Phases and Max Androgen Phases).There was a few report of pro bodybuilders who layered TGF into a Max Androgen Phase as a means of decreasing fat accumulation during mass weight gain protocols.
L. Rea (2002) - Chemical Muscle Enhancement Bodybuilders Desk Reference