Rat study finds limited melatonin benefit in hyperprolactinemia

A new Frontiers in Veterinary Science study reports that experimentally induced hyperprolactinemia caused measurable structural changes in the stomach, duodenum, and liver of male rats, and that exogenous melatonin offered only limited protection. In the 60-day experiment, researchers induced hyperprolactinemia with daily domperidone injections and treated one group with subcutaneous melatonin. Compared with controls, hyperprolactinemic rats showed higher body weight, gastric lumen dilation, changes in duodenal villi and microvilli, and liver findings including microsteatosis, fewer Kupffer cells, and more binucleated hepatocytes. Melatonin appeared to normalize body weight trends and affected one duodenal histochemical measure, but it didn’t consistently reverse the broader tissue changes. (frontiersin.org)

Why it matters: For veterinary professionals, the paper adds to a small but growing body of work showing that hyperprolactinemia may have gastrointestinal and hepatic effects beyond its better-known reproductive consequences. It also tempers enthusiasm around melatonin as a broadly protective intervention in endocrine-linked tissue injury: while melatonin has been described in prior literature as active in the gastrointestinal tract and liver, this rat model did not show consistent organ-level rescue. That makes the study more useful as a cautionary signal than as a practice-changing therapeutic advance. (frontiersin.org)

What to watch: Watch for follow-up studies testing different melatonin doses, routes, durations, and species to see whether the limited effect here reflects the model, the protocol, or a true ceiling on benefit. (frontiersin.org)