Pregnant mommas must make a tough choice: preserve energy for themselves or invest it in their little ones. Now new research suggests that higher levels of the hormone leptin may fool a hamster’s brain into thinking there is energy to spare, promoting larger litters at the expense of the mother’s health. Researchers report the results in an upcoming Proceedings of the Royal Society B.
“I think the findings are compelling,” comments behavioral biologist Randy Nelson of Ohio State University in Columbus. He says this is the first evidence he has seen suggesting that leptin plays a part in how a mother invests her energy.
Secreted mostly by fat tissue, leptin seems to tell the body when to stop eating. But it has also been shown to affect rodents’ immune function and reproduction. When stressed mice have lowered immune defenses, doses of leptin can restore the activity to normal levels. A number of stressed mammal species treated with leptin will reproduce when they normally would not do so.