From the Research
Growth hormone (GH) inhibits AMPK (AMP-activated protein kinase) activity in multiple tissues, leading to a shift in metabolism away from fatty acid oxidation and toward lipogenesis and gluconeogenesis, as supported by the most recent study 1. This inhibition is particularly important in the liver, where AMPK promotes fatty acid oxidation. The mechanism of GH-mediated AMPK inhibition involves the activation of the JAK-STAT signaling pathway, leading to increased production of SOCS3 (suppressor of cytokine signaling 3), which directly inhibits AMPK by preventing its phosphorylation and activation. Additionally, GH increases insulin-like growth factor 1 (IGF-1), which activates the PI3K/Akt pathway that further suppresses AMPK activity.
Some key points to consider:
- The diabetogenic action of GH has been well-described in previous in vivo studies, and its effects on glucose metabolism and insulin resistance have been reviewed 2.
- AMPK is a master sensor of cellular energy levels and a crucial regulator of nutrient metabolism, including glucose, lipid, and protein metabolism 3.
- Autophagy, a lysosome-dependent catabolic program, is closely connected with nutrient signaling modules, including AMPK, to fine-tune the metabolic pathways in response to various cellular cues 4.
- The relationship between GH and AMPK has important implications for understanding the metabolic effects of GH, including its tendency to increase blood glucose levels and promote lipolysis in adipose tissue while simultaneously enhancing protein synthesis in muscle.
The most recent study 1 provides evidence for the involvement of hypothalamic AMPK signaling in the regulation of pituitary GH secretion, highlighting the complex interplay between GH and AMPK in the regulation of metabolism. Overall, the current evidence suggests that GH inhibits AMPK activity, leading to a shift in metabolism that can have significant effects on glucose and lipid metabolism, as well as protein synthesis.