The team of scientists from the UK, US, and Australia studied a sheep animal model of thyroid hormone deficiency before birth.
They measured levels of three hormones: thyroid hormone, insulin and leptin. They also studied the rate of cell division and the number of beta cells — the cells of the pancreas that store and secrete insulin.
Normal levels of thyroid hormone during pregnancy are vital for proper development of the baby. Approximately 1 in 3000 babies are born each year with an under-developed thyroid gland (congenital hypothyroidism) and 2-4% of pregnant mothers are affected by thyroid disease.
Therefore, it is important to figure out how thyroid hormone affects the foetal pancreas, and susceptibility to pancreatic disorders and type 2 diabetes in later life.
This new research found that thyroid hormone levels impair the growth and development the fetal pancreas by affecting the number and rate of cell division of the beta cells.
Learning the full picture of how thyroid hormone influences the foetal pancreas will help ensure the health of babies with congenital thyroid hormone disorders and those born to mothers with similar disorders.
Commenting on the study, first author Dr Shelley Harris, said: “The study highlights a novel role for thyroid hormones in regulating pancreatic development and opens up new questions to be explored.”
Senior author Dr Alison J. Forhead added: “In individuals with low thyroid hormone before birth, abnormalities in beta-cell development may lead to increased risk of pancreatic disorders and type 2 diabetes in later life.”
The study was a collaboration between scientists at Oxford Brookes University, University of Cambridge, University of Arizona, and University of Western Australia.
The full paper is entitled “Hypothyroidism in utero stimulates pancreatic beta cell proliferation and hyperinsulinaemia in the ovine fetus during late gestation”, published in The Journal of Physiology.