Blocking the Growth Hormone Receptor Extends Mouse Lifespan, Landmark Study Finds

One of the most reliable ways to make a laboratory mouse live longer is to cripple its growth hormone signaling. Mutations that blunt the GH/IGF-1 axis have produced some of the most dramatic lifespan extensions ever recorded in rodents, including the world’s longest-lived laboratory mouse, a growth hormone receptor null animal that died just one week short of its fifth birthday. Yet these achievements have always carried an asterisk: they were created by genetic engineering, a strategy that cannot be translated into a pill or injection for people. A new study published in Aging Cell now closes that gap, providing the first formal proof that pharmacologically blocking the growth hormone receptor—rather than deleting the gene—can extend lifespan in mice that produce growth hormone normally.

The research, conducted by Edward O. List, Darlene E. Berryman, John J. Kopchick, and colleagues at Ohio University, relied on a transgenic mouse line that expresses a growth hormone antagonist known as GHA. This molecule has a storied history. In the early 1990s, the same laboratory discovered that substituting a single, highly conserved glycine residue in the growth hormone molecule with a lysine converts the hormone into a potent receptor antagonist. Instead of activating the growth hormone receptor, the altered protein binds it and jams it. That discovery ultimately led to the development of Pegvisomant, the only FDA-approved growth hormone receptor antagonist, used to treat acromegaly. Crucially, decades of clinical use have established that reducing growth hormone action through receptor antagonism is practical and well tolerated in humans.

There was, however, a technical obstacle standing between Pegvisomant and rodent longevity studies: the drug binds the mouse growth hormone receptor poorly, making direct lifespan testing in rodents impossible. The GHA transgenic mice were designed to circumvent exactly this problem. These animals carry a bovine growth hormone minigene, driven by the mouse metallothionein-1 promoter, in which the glycine at position 119 has been replaced by lysine—the same G119K mutation that underlies the human drug. The transgene is expressed in multiple tissues, with the liver showing the greatest expression, and circulating levels of the antagonist reach approximately 5.0 micrograms per milliliter. The result is a roughly 70 percent reduction in serum IGF-1 and a body weight at two months that is only about 59 percent of wild type. After more than twenty generations of backcrossing, the line now sits on a clean C57BL/6J inbred background.

The new study matters partly because it corrects an embarrassing wrinkle in the lab’s own record. A colony scan published in 2003 had failed to detect extended longevity in GHA mice, a result that appeared to contradict the consensus that reduced growth hormone signaling prolongs life. But that earlier effort was never a proper aging experiment. Lifespan was inferred from deaths recorded among a small number of breeding-colony animals, between 22 and 33 per group, mixing breeders and non-breeders, and the survival data were compared with ANOVA rather than the log-rank test that is standard in the field. Although a trend toward longer life, especially in females, was visible even then, the analysis lacked the power and the statistical framework to detect it.

The current investigation was designed to settle the question definitively. The researchers set aside 351 mice—GHA and wild type, with group sizes ranging from 45 to 133—specifically for survival analysis. No breeders were included, and the animals were used for no other measurements. In every comparison, pooled sexes, males only, and females only, the GHA mice lived significantly longer by log-rank analysis. Female GHA mice showed the most striking gains: mean lifespan increased by 28.8 percent, or 186 days; median lifespan rose 23.9 percent, or 160 days; and maximal lifespan climbed 29.1 percent, an additional 265 days. Males benefited as well, though more modestly, with mean lifespan up 7.6 percent (57 days), median lifespan up 2.9 percent (23 days), and maximal lifespan up 12.2 percent (121 days). The pronounced sex difference, the authors note, suggests that sex hormones may modulate the longevity response and deserve dedicated study.

Longer life is only valuable if it comes with preserved function, so the team also examined a separate cohort of two-year-old mice for frailty, grip strength, body composition, and fat distribution. Both male and female GHA mice displayed superior grip strength and significantly reduced frailty scores compared with wild type controls, despite carrying more body fat. That fat was not distributed randomly: it accumulated primarily in the subcutaneous depot in both sexes and in the retroperitoneal depot in males, while mesenteric visceral fat remained comparatively spared. This pattern echoes what has been seen in other growth hormone-compromised mice, which often exhibit a paradoxical “healthy obese” phenotype—marked adiposity accompanied by enhanced insulin sensitivity, elevated adiponectin, and preserved glucose homeostasis.

The findings are all the more impressive given the genetic background of the animals. C57BL/6J is an inbred strain that typically dampens the effects of longevity interventions because it lacks the hybrid vigor of mixed stocks; for this reason, the National Institute on Aging’s Interventions Testing Program conducts its aging studies in genetically heterogeneous mice. Detecting robust lifespan and frailty benefits on a C57BL/6J background therefore strengthens the case that growth hormone receptor antagonism is a genuinely potent gerotherapeutic strategy. The team is now repeating the aging studies in a mixed genetic background to confirm and extend the result.

Why would dampening a hormone best known for driving childhood growth slow aging? The mechanisms are presumed to overlap with those characterized in other long-lived mouse lines with reduced growth hormone action, such as growth hormone receptor null, Snell, Ames, and Little mice, though likely to a lesser degree because GHA mice retain partial signaling. Across these models, researchers have documented improved insulin sensitivity, reduced tissue inflammation, greater metabolic flexibility, exceptional cancer resistance, reduced adipose senescence, attenuated immunosenescence, decreased insulin exposure and mTOR signaling, AMPK activation, and enhanced antioxidant defenses, along with preserved cognition, physical function, and stress resilience into late life. Earlier work on GHA mice specifically has reported improved cognitive function, reduced fibrosis, reduced cancer susceptibility, and protection from osteoarthritis and kidney damage. Remarkably, even though the mice are obese, they are protected from hyperinsulinemia and glucose intolerance when fed a high-fat diet.

Recent biology also strengthens the rationale for intervening later in life. Although circulating growth hormone levels decline with age, local production of the hormone within aging tissues and tumors can actually increase. Growth hormone is a component of the senescence-associated secretory phenotype, the inflammatory cocktail emitted by senescent cells, meaning that autocrine and paracrine growth hormone signaling may remain elevated in aged tissues even as endocrine levels fall. Because the GHA transgene is expressed broadly across tissues, the model partially mimics what a systemically administered antagonist could achieve in an older patient. Notably, prior work from the same group showed that removing the growth hormone receptor later in life, or even in a single tissue, is sufficient to extend lifespan, indicating that the target remains relevant well beyond development.

The authors are careful to frame the promise alongside the caveats. Severe loss of growth hormone action in humans can impair the heart, kidney, pancreas, skeletal muscle, and adipose tissue, and replacement therapy can restore cardiac mass, exercise capacity, and renal function in deficient patients. Some structural changes seen with low growth hormone signaling, such as reduced pancreatic islet size or increased adiposity, do not necessarily translate into dysfunction under ordinary conditions; the long-lived mice are glucose tolerant under basal circumstances but struggle to clear a large glucose bolus. The significance of the new study, the researchers emphasize, lies not in reconfirming that genetic removal of growth hormone action benefits mice, but in demonstrating for the first time that antagonism—a clinically achievable intervention—can extend lifespan in growth hormone-producing animals. With a safe, FDA-approved antagonist already in the clinic, the foundation is now in place to test whether growth hormone receptor blockade, delivered at different doses and life stages, can become a genuine anti-aging therapy for humans.

Subject of Research: Growth hormone receptor antagonism as a pharmacological intervention to extend lifespan and healthspan in mice

Article Title: Growth Hormone Receptor Antagonism Extends Lifespan

Article References: List, E. O., Berryman, D. E., Lach, G. S., Minto, D. F., Weese, K., & Kopchick, J. J. (2026). Growth Hormone Receptor Antagonism Extends Lifespan. Aging Cell, 25(9), Article e70697. https://doi.org/10.1111/acel.70697

Image Credits: AI Generated

DOI: 10.1111/acel.70697

Keywords: growth hormone, growth hormone receptor antagonist, aging, lifespan, IGF-1, Pegvisomant, GHA mice, frailty, longevity, gerotherapeutics, Aging Cell, mouse models