Researchers at the University of Alberta, Canada, reasoned that blocking the action of TGH would lead to better blood lipid profiles, but might also result in accumulation of triacylglycerol in the liver. However, they have found that mice lacking TGH (tgh-/-) display global metabolic benefits with no obvious down-side. In both fasted- and fed-states, the animals had reduced plasma triacylglycerol, apolipoprotein B, and fatty acid levels. Despite the attenuation of very low-density lipoprotein (VLDL) secretion, TGH deficiency did not increase hepatic triacylglycerol levels. The tgh-/- mice exhibited increased food intake and energy expenditure without change in body weight, and these metabolic changes are accompanied by improved insulin sensitivity and glucose tolerance.
The authors of the study, published in Cell Metabolism, suggest that pharmacological inhibition of TGH could be a useful therapeutic target, although cautioning that further work is required. It may be desirable to target TGH in specific tissues (e.g. hepatic versus adipose) but those subtleties have yet to be established.