The Roles of the Thyroid and Thyroid Hormones in the Pancreas

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The butterfly-shaped gland produces hormones that participate in various functions in the body.

Levels of thyroid hormones have a strong influence on different organs and tissues in the human body, even though we are not aware of it.

In this post, we are going to focus on the pancreas and describe how thyroid function and hormones produced by this gland influence this organ.

Let’s learn more about the relationship between thyroid and pancreas.

What is the pancreas?

How much do we really know about pancreas? The truth is that we don’t know as much as we should so at the very beginning, it’s important to address a thing or two about this organ.

The pancreas is the organ in the upper left abdomen, but it is also referred to as a gland. Its primary function is to convert the food we eat into energy or fuel for cells in our body. More precisely, the pancreas has two main functions: regulate blood sugar and aid digestion.

When it comes to endocrine function, pancreas contains islet cells that create and release their hormones directly into the bloodstream. These hormones are insulin and glucagon. The latter raises blood sugar levels while insulin lowers them.

On the other hand, the exocrine function of pancreas involves exocrine glands that produce enzymes we need for proper digestion. Basically, the pancreas produces various enzymes to break down different nutrients such as protein, carbohydrates, fats, and others[i].

Thyroid and pancreas relationship

Our body is like a unique system where everything is connected, although we do not think about it that way. Hormones are particularly intertwined. Excessive or low levels of one hormone can negatively influence others.

Glands that produce them can have a major effect on other glands. Both thyroid and pancreas produce hormones that our body requires to function properly.

Therefore, it is not a far-fetched idea that thyroid and its hormones could affect pancreatic function. What is their relationship really like?

Low thyroid hormones reduce exocrine pancreatic function

Despite the fact that the effects of thyroid hormones on many organs and glands have been widely explored, the knowledge about the role of the butterfly-shaped gland in pancreas development and function has improved slowly.

Gullo et al. published a study in Gastroenterology, where they explored the impact of thyroid hormones on the exocrine function of pancreas. For the purpose of the study, scientists enrolled 15 subjects with hypothyroidism and 15 healthy participants.

Nine of 15 hypothyroid subjects were also studied after they had reached euthyroid state following thyroxine treatment.

Results showed that compared to healthy participants, their hypothyroid counterparts experienced a decreased function of pancreas. However, thyroxine treatment restored pancreatic function to normal.

Low thyroid hormones i.e., hypothyroidism also decreased secretion of enzymes. This means that the exocrine function of pancreas (production of enzymes for digestion) was reduced.

Based on these findings scientists concluded that the thyroid gland plays an essential role in maintaining the functional integrity of exocrine pancreas in humans[ii].

What about euthyroid state and pancreas?

When thyroid hormone levels decrease or increase, consequences are felt throughout the body, and pancreas is not an exception.

But does it mean that only imbalances of thyroid hormones can somehow impact pancreatic function? Not really?

Even in euthyroid men and women serum concentrations of TSH, T4, and T3 have been directly associated with the serum glucose and insulin levels as well as insulin resistance[iii],[iv].

In other words, the influence of thyroid and its hormones on pancreas and hormones produced by it is stronger than we think. This only shows that thyroid contributes to pancreatic function in all its states whether it’s functioning normally or not.

Hypothyroidism and pancreas

As mentioned above, low thyroid hormone levels can negatively affect pancreatic function. But the effect of this common condition on pancreas function is more complicated than we realize.

In addition to the presence of adipocytes (fat cells), an elevation of the number of islet cells and the extracellular matrix, evidence shows that hypothyroidism also affects the presence of blood vessels into the islets.

That way, hypothyroidism can support the ongoing inflammatory process in pancreas.

Rodriguez-Castelan et al. found that hypothyroidism reduced the cell number in large and medium islets, but not in smaller cells.

What’s more, cell proliferation increased in smaller islets.

However, immunoreactivity of thyroid hormone receptors was increased by hypothyroidism in all islet sizes. Scientists concluded that hypothyroidism acts differently in islet cells depending on their size[v].

In a different study, Rodriguez-Castelan et al. found that hypothyroidism induces pancreatitis and insulitis[vi]. Pancreatitis is a disease where the pancreas is inflamed. It can be acute or chronic. On the other hand, insulitis is an inflammation of the Langerhans islets.

This only confirms why it is so important to manage hypothyroidism properly. Adequate treatment and a healthy lifestyle can manage not only symptoms of hypothyroidism but also prevent potential complications affecting the pancreas.

Low thyroid hormone in pregnancy – pancreas problems

Woman’s health and wellbeing during pregnancy have a strong impact on the growth and development of the baby in the womb.

Harris et al. found that low thyroid hormone in pregnancy can alter fetal pancreas development. The study revealed that thyroid hormones are important regulators of growth and maturation before birth.

Scientists used a sheep model to analyze whether thyroid hormone affects β-cell proliferation in fetal pancreatic islets. They discovered that hypothyroidism in the fetus has various effects on islets in the pancreas. The effects of hypothyroidism on the development of the fetal endocrine pancreas may have short- or long-term consequences for growth and metabolism in offspring.

For example, adult offspring of hypothyroid rats experience reduced glucose tolerance and lower glucose-stimulated insulin secretion from isolated pancreatic islets.

What does all this mean?

Basically, scientists confirmed that hypothyroidism in mothers could negatively affect pancreas development in their children. Consequences of this problem can be acute or short-term and chronic or long-term. The study highlights the significance of physiological exposure to adequate levels of thyroid hormone, insulin, and leptin in utero[vii].

Pregnant women need to see their doctor regularly, especially if they already have problems with hypothyroidism or insulin resistance. The doctor will recommend a proper management technique that will help expectant mothers to make sure their baby’s growth and development is undisturbed.

Other studies have also shown that thyroid hormone has a major impact on pancreas development and is vital for glucose metabolism and homeostasis[viii]. Healthy thyroid hormone levels in mothers allow the fetus to avoid exposure to hypothyroidism, which could negatively affect pancreas function, insulin, and glucose.

Pancreatic surgery reduces thyroid function

Throughout this post, we have discussed how the thyroid and its hormone influence cells and blood vessels in the pancreas and overall pancreatic function.

But, pancreas and thyroid have a two-way relationship. Evidence shows that pancreatic surgery reduces the function of the butterfly-shaped gland.

Several factors could explain this outcome. For example, it could be down to an increased proportion of free thyroid hormones after the surgery caused by a lower concentration of thyroid hormone-binding proteins.

Moreover, pancreatic surgery is a serious intervention with potentially severe complications and thereby lower free thyroid hormone levels could be a manifestation of deep and serious metabolic disturbances[ix].

Thyroid hormones regulate insulin

Cortizo et al. found that deficit in thyroid hormone levels is accompanied by smaller glucose-induced insulin secretion.

When T3 and T4 hormone levels returned to normal, the metabolic and secretory changes normalized as well. They concluded that insulin secretion is regulated at least to some extent by thyroid hormone levels[x].

In other words, low thyroid hormone levels impair regulation of insulin, thereby negatively affecting glucose metabolism. This could explain why thyroid problems are also strongly associated with insulin resistance and diabetes.

More research needed

A growing body of evidence confirms that thyroid and hormones produced by the gland contribute to the pancreatic function. After all, some thyroid hormone receptors are found in the pancreas.

That is a major hint of the relationship between the two. Moreover, decreased production of thyroid hormones can negatively affect cells in the pancreas, impair insulin secretion, induce inflammation, induces pancreatitis and insulitis and decrease the production of enzymes. Let’s not forget that hypothyroidism in pregnant women can lower pancreatic function in their babies.

Despite these important discoveries, more research is needed to uncover all the mechanisms of action that underlies pancreas and thyroid link. Even though hormones produced by both pancreas and thyroid influence one another, the relationship between butterfly-shaped gland and pancreas is poorly elucidated.

Further research would give us a detailed insight into the connection between the two but also potentially pave the wave to new treatment routes for problems affecting them.

How to tell if I have pancreas problems?

Pancreatitis is the most common pancreas-related problem. As mentioned above, it is a condition indicated by inflammation of the pancreas. Symptoms associated with acute pancreatitis include:

  • Nausea and vomiting
  • Fever
  • Pain in upper abdomen radiating to the back, aggravated by eating particularly high-fat foods
  • Tender and swollen abdomen
  • Increased heart rate

On the other hand, chronic pancreatitis involves similar symptoms, but more severe. Some people feel constant pain in the upper abdomen and experience problems such as diarrhea and weight loss. Diabetes may also occur.

Managing pancreas problems

If you have hypothyroidism or other thyroid problems, it is of huge importance to manage your condition properly. Adhere to the treatment plan recommended by the doctor and introduce necessary lifestyle measures that will lower the intensity of symptoms, but also prevent complications. As seen throughout this post, thyroid problems can impair the pancreas function. Therefore, one way to reduce the risk of pancreas problems such as pancreatitis is to ensure your thyroid gland is healthy.

If you have pancreatitis, your doctor will recommend medications to alleviate pain, IV, and surgery if necessary. Patients may also need to take enzyme supplements that will improve their digestion.

Following doctor’s orders is vital because treatment is tailored for each patient based on the severity of the condition.

Certain lifestyle adjustments are necessary. For example, you should limit or avoid alcohol consumption and quit smoking. Make sure you stay hydrated throughout the day and eat a well-balanced diet.

When it comes to beverages, you need to drink more water and avoid sugar-laden drinks. Your diet should focus on protein-rich food, low in animal fats, and abundant in antioxidants. For instance, you can try lean meats, beans, and lentils, clear soups (avoid creamy soups).

Basically, you should focus on the consumption of foods that are easy to digest. Processed and refined foods are difficult to digest, meaning your pancreas would need to work extra hard.

Of course, fruits and vegetables can not only improve your digestion but also supply your body with much-needed antioxidants. Let’s not forget that many fruit and vegetable sources also have anti-inflammatory properties which come handy in case of inflammation of the pancreas.

Conclusion

Both the pancreas and thyroid have important roles in the human body.

We need them to function properly if we want to stay healthy and strong. Both pancreas and thyroid produce hormones that participate in a number of functions.

Pancreas and thyroid have a lot in common, and it comes as no wonder they have a strong relationship. That being said, the link between the two is still poorly elucidated, and it will be necessary to change that.

Studies have shown that thyroid hormones regulate insulin secretion to some extent, participate in pancreas development, and their deficit could induce pancreatitis, insulitis, and other problems.

References

[i] The pancreas and its functions, Columbia / Surgery. Retrieved from: https://columbiasurgery.org/pancreas/pancreas-and-its-functions

[ii] Gullo L, Pezzilli R, Bellanova B, et al. (1991). Influence of the thyroid on exocrine pancreatic function. Gastroenterology, 100(5 Pt 1):1392-6. Retrieved from: https://www.ncbi.nlm.nih.gov/pubmed/2013384

[iii] Ortega E, Koska J, Pannacciulli N, et al. (2008). Free triiodothyronine plasma concentrations are positively associated with insulin secretion in euthyroid individuals. European Journal of Endocrinology, 158(2):217-221. Doi: 10.1530/EJE-07-0592. Retrieved from: https://eje.bioscientifica.com/view/journals/eje/158/2/217.xml

[iv] Luna-Vazquez F, Cruz-Lumbreras R, Rodriguez-Castelan J, et al. (2014). Association between the serum concentration of triiodothyronine with components of metabolic syndrome, cardiovascular risk, and diet in euthyroid postmenopausal women without and with metabolic syndrome. Springer Plus, 3, article number 266. Doi: 10.1186/2193-1801-3-266. Retrieved from: https://springerplus.springeropen.com/articles/10.1186/2193-1801-3-266

[v] Rodriguez-Castelan J, Nicolas L, Morimoto S, Cuevas E. (2014). The Langerhans islet cells of female rabbits are differentially affected by hypothyroidism depending on the islet size. Endocrine, 48(3):811-817. Doi: 10.1007/s120120-014-0418-4. Retrieved from: https://link.springer.com/article/10.1007%2Fs12020-014-0418-4

[vi] Rodriguez-Castelan J, Martinez-Gomez M, Castelan F, Cuevas E. (2015). Hypothyroidism affects vascularization and promotes immune cells infiltration into pancreatic cells of female rabbits. International Journal of Endocrinology. Doi: 10.1155/2015/917806. Retrieved from: https://www.hindawi.com/journals/ije/2015/917806/

[vii] Harris SE, De Blasio MJ, Davis MA, et al. (2017). Hypothyroidism in utero stimulates pancreatic beta-cell proliferation and hyperinsulinemia in the ovine fetus during late gestation. The Journal of Physiology, 595(11):3331-3343. Doi: 10.1113/JP273555. Retrieved from: https://physoc.onlinelibrary.wiley.com/doi/full/10.1113/JP273555

[viii] Matsuda H, Mullapudi ST, Zhang Y, et al. (2017). Thyroid hormone coordinates pancreatic islet maturation during the zebrafish larval-to-juvenile transition to maintain glucose homeostasis. Diabetes, 66(10):2623-2635. Doi: 10.2337/db16-1476. Retrieved from: https://diabetes.diabetesjournals.org/content/66/10/2623

[ix] Wojciechowska-Durczynska K, Zygmunt A, Durczynski A, et al. (2012). The influence of liver and pancreas surgery on the thyroid function. Thyroid Research, 5, article number 21. Doi:10.1186/1756-6614-5-21. Retrieved from: https://thyroidresearchjournal.biomedcentral.com/articles/10.1186/1756-6614-5-21

[x] Cortizo AM, Gomez-Dumm CL, Gagliardino JJ. (1985). Effect of thyroid hormone levels upon pancreatic islet function. Acta Physiologica et Pharmacologica Latinoamerica, 35(2):181-191. Retrieved from: https://www.ncbi.nlm.nih.gov/pubmed/2938405

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