Growth Hormone Makes Weight Loss Harder

For decades, scientists have been trying to understand why it’s so difficult to maintain the weight achieved after the sacrifices of a successful diet and why it’s so easy to regain the lost weight. Leptin has hitherto been considered the main hormone that acts to conserve energy when we’re hungry,” Donato said. Bloodstream leptin levels are known to fall in response to weight loss, he explains, but this knowledge has never resulted in the creation of a successful diet or therapy with leptin that could enable subjects to lose weight and not regain it soon afterwards. “The weight loss process evidently involves several metabolic processes and several hormones besides leptin. This is where GH comes in. We found that in response to weight loss, GH acts on the brain in a similar way to leptin. However, while leptin levels fall, the opposite happens to GH. Weight loss triggers a rise in bloodstream levels of GH,” Donato said. “In the recently published article, we show that central growth hormone signaling also promotes neuroendocrine adaptations during food deprivation.” GH receptors in the brain are located in the hypothalamus, the highest center of the autonomic nervous system. Impulses from the hypothalamus influence the cells of the neurovegetative system and regulate smooth muscle tissue in the gut and blood vessels, cardiac muscle, all glands, and the kidneys, among other organs. The researchers found that GH receptors in the hypothalamus specifically activate a small population of neurons called AgRP, which is short for agouti-related protein. AgRP neurons in turn increase the production of AgRP, which increases appetite and diminishes energy metabolism and expenditure. “AgRP is one of the most powerful appetite stimulants. It’s curious to see how a small number of AgRP neurons, only a few thousand out of the billions of neurons in the hypothalamus, can play such an important role,” Donato said. https://www.technologynetworks.com/cell-science/news/gh-also-key-to-neuroendocrine-adapation-to-weight-loss-318211?utm_campaign=NEWSLETTER_TN_Breaking%20Science%20News&utm_source=hs_email&utm_medium=email&utm_content=71749895&_hsenc=p2ANqtz-_uzQihMVJEqv30s6xeIjNbHPuahcVNPPO9xfI4LmKpS_uBd4m6xXOJdFnYdXTZIVu6AOyi2ny3NbxPTh-JTGZQzmXG_Q&_hsmi=71749895