An in vivo study of aging mice found that epitalon treatment significantly reduced the incidence of chromosomal aberrations in both wild-type mice and mice characterized by an accelerated aging phenotype, which was consistent with an increase in telomere length. Another study in aging rats found that epitalon increased activity of the antioxidant enzymes superoxide dismutase, glutathione peroxidase, and glutathione -S-transferase. In experiments with one-year-old female C3H/He mice, Epitalon reduced the number of spontaneous tumors and the number of metastases in mice that did develop spontaneous tumors, and was hypothesized to have tumor suppressor and anti-metastatic properties. In a study of chickens undergoing neonatal pituitectomy and subsequent maturation, epitalon promoted the recovery of morphological structure of the thymus, as well as the structure and function of the thyroid gland. Epitalon appears to increase lymphocyte proliferation in the thymus, presumably increasing interferon gamma produced by T cells. Another study in older rats showed that constant light exposure, or a natural light regimen typical in northern regions, increased the rats' lifespan.