Thyroxine: Definition, Function And Test

Thyroxine is the main hormone secreted in the blood stream by thyroid gland. It plays an important role in digestion, heart and muscle function, brain development and bone maintenance.

What is Thyroxine?
Thyroxine is the main hormone secreted in the blood stream by thyroid gland. It is an inactive form and most of these are actively converted into an active form called triiodothyronine by the organs such as the liver and kidneys. Thyroid hormones play an important role in regulating the body’s metabolic rate, heart and digestive function, muscle control, brain development and bone maintenance.

A thyroxine test helps diagnose thyroid disorders. Thyroid is a small, butterfly-shaped gland located near the throat. Your thyroid produces hormone which regulates the way your body uses energy. It plays an important role in regulating your weight, body temperature, muscular strength, and even your mood. Thyroxine, also called T4, is a type of thyroid hormone. This test measures the level of T4 in your blood. Very high or very small T4 may indicate thyroid disease.

T4 Hormones come in Two Forms:
•  Free T4, which enters the body tissue where it is needed
•  Bound T4, which is linked to the protein, prevents it from entering body tissues

A test which measures both free and bound T4 is called total T4 test. Other tests only make free T4 measures. Total T4 testing is considered to be more accurate than the total T4 test for the investigation of thyroid function.

Other Names:
Free thyroxine, free T4, Total T4 concentration, Thyroxine screen, Free T4 concentration

what is it Used For?
A T4 test is used to evaluate thyroid function and diagnose thyroid disease.

How is Thyroxine Controlled?
The production and release of thyroid hormone, thyroxacine and triiodothyronine is controlled by a feedback loop system, which involves the hypothalamus in the brain and pituitary and thyroid glands. The hypothalamus passes through thyrotropin-releasing hormone which, in turn, stimulates the pituitary gland to produce thyroid stimulating hormones. This hormone stimulates the production of thyroid hormones, thyroxine and triiodothyronine by thyroid gland.

This hormone production system is controlled by the feedback loop so that when the level of thyroid hormone (thyroxine and triiodothyronine) increases, they prevent the release of thyrotropin-releasing hormones and thyroid stimulating hormones. This system allows the body to maintain continuous levels of thyroid hormone in the body.

Why do I Need a Thyroxine Test?
Thyroid disease is more common in women and usually occurs below 40 years of age. It also participates in families. If your family member has thyroid disease or if there is a symptom of having too much thyroid hormone in your blood, then there is a condition called hyperthyroidism, or symptoms of very low thyroid hormone, is a condition called hypothyroidism.

Symptoms of hyperthyroidism, also known as hyperactive thyroid, include:
•  Anxiety
•  Weight event
•  Wrinkles in hands
•  Increased heart rate
•  Swelling
•  Eye bounce
•  Insomnia

Symptoms of hypothyroidism, also called underactive thyroid, include:
•  Weight gain
•  Fatigue
•  Hair fall
•  Low tolerance for cold temperatures
•  Irregular menstrual period
•  Constipation

What Happens During Thyroxin Test?
A health care professional will take a blood sample from a vein in his arm, using a small needle. After inserting the needle, a small amount of blood will be collected in the test tube or vial. When the needle goes in or out, you can feel a little sting. It usually takes less than five minutes.

Do I Need To Do Anything To Prepare For The Test?
You do not need any special preparation for thyroid blood tests. If your health care provider has ordered to do more testing on your blood sample, you may need to eat fast (eating or drinking) several hours before the test. If you have any special instructions to follow, your health care provider will tell you.

Is There Any Risk To The Test?
There is very little risk to blood tests. At that place, you may have some pain or injury where the needle was put, but most of the symptoms go away quickly.

What Do The Results Mean?
Your results can come in the form of total T4, free T4, or a free T4 index.
•  The free T4 index contains a formula that compares to free and bound T4.
•  Higher levels of any of these tests (total T4, free T4, or free T4 index) can indicate an overactive thyroid, also called hyperthyroidism.
•  The lowest levels of any of these tests (total T4, free T4, or free T4 index) can indicate an underactive thyroid, also called hypothyroidism.

If the results of your T4 test are not normal, then your health care provider will order more thyroid tests to help diagnose. These may include:
•  T3 thyroid hormone test. T3 is another hormone created by thyroid.
•  A TSH (thyroid stimulating hormone) test. TSH is a hormone made by the pituitary gland. It stimulates the thyroid to produce T4 and T3 hormones.
•  Test for the diagnosis of grave disease, an autoimmune illness that causes hyperthyroidism
•  Test for the diagnosis of Hashimoto’s thyroiditis, an autoimmune disease that causes hypothyroidism

Is There Something Else That I Need To Know About Thyroid Test?
Thyroid changes may occur during pregnancy. These changes are not usually important, but some women may develop thyroid disease during pregnancy. Hyperthyroidism is present in almost every 500 pregnancies, whereas hypothyroidism is almost one in every 250 pregnancies. Hypothyroidism, and less often, hypothyroidism, can survive even after pregnancy. If you develop thyroid conditions during pregnancy, then your health care provider will monitor your condition after your baby is born. In addition, if you have a history of thyroid disease, then if you are pregnant or are thinking of getting pregnant then be sure to talk to your healthcare provider.

What if I Have too Much Thyroxine?
The release of excess thyroxine in the blood stream is known as thyrotoxicosis. This may be due to the hyperthyroidism of hyperthyroidism, such as swelling of the grave disease, thyroid or benign tumor. Thyrotoxicosis can be identified by a goiter, which is due to the expansion of the thyroid gland, due to the swelling of the neck. Other symptoms of thyrotoxicosis include heat, weight loss, increased appetite, increased bowel movement, irregular menstrual cycle, fast or irregular heartbeats, tilt, weariness, irritability, shivering, hair loss / loss and retrogression of the eyelids. ‘Stare’ ‘presence.

What if I Have Very Little Thyroxine?
Very low production of thyroxine by thyroid gland is known as hypothyroidism. This may be due to the use of autounein diseases, bad iodine intake or some medicines. Occasionally, the reason is unknown. Thyroid hormones are essential for physical and mental development, so hypothyroidism that is not treated during birth or during childhood can decrease mental disorder and reduce development.

Hypothyroidism in adults causes less metabolism. As a result, fatigue, intolerance of cold temperatures, low heart rate, weight gain, loss of appetite, poor memory, depression, muscle stiffness and low fertility may be. See the article on hypothyroidism for more information.

Chemical Formula of Thyroxine
Thyroxine, also called 3,5,3′,5′-tetraiodothyronine or T4, is one of the two major hormones secreted by thyroid gland (the second is triiodothyronine). The main function of thyroxine is to stimulate oxygen consumption and thus stimulate metabolism of all cells and tissues in the body. Thyroxine is produced by amino acid tyrosine by the molecular joint of iodine, while later the protein is associated with thyroglobulin. Excessive secretion of thyroxine in the body is known as hyperthyroidism, and secretion of its deficiency is called hypothyroidism. The chemical composition of thyroxine is

thyroxine, chemical compound

One thought on “Thyroxine: Definition, Function And Test

  1. Hey, how’s it going?

    I want to pass along some very important news that everyone needs to hear!

    In December of 2017, Donald Trump made history by recognizing Jerusalem as the capital of Israel. Why is this big news? Because by this the Jewish people of Israel are now able to press forward in bringing about the Third Temple prophesied in the Bible.

    Jewish Rabbis have publicly announced that their Messiah will be revealed in the coming years who will be a leader and spiritual guide to all nations, gathering all religions under the worship of one God.

    Biblical prophecy tells us that this Jewish Messiah who will take the stage will be the antichrist “who opposes and exalts himself above all that is called God or that is worshiped, so that he sits as God in the temple of God, showing himself that he is God” (2 Thessalonians 2:4). For a time he will bring about a false peace, but “Therefore when you see the ‘abomination of desolation,’ spoken of by Daniel the prophet, standing in the holy place (Matthew 24:15)…then there will be great tribulation, such as has not been since the beginning of the world until this time, no, nor ever shall be” (Matthew 24:21).

    More importantly, the power that runs the world wants to put a RFID microchip in our body making us total slaves to them. This chip matches perfectly with the Mark of the Beast in the Bible, more specifically in Revelation 13:16-18:

    “He causes all, both small and great, rich and poor, free and slave, to receive a mark on their right hand or on their foreheads, and that no one may buy or sell except one who has the mark or the name of the beast, or the number of his name.

    Here is wisdom. Let him who has understanding calculate the number of the beast, for it is the number of a man: His number is 666.”

    Referring to the last days, this could only be speaking of a cashless society, which we have yet to see, but are heading towards. Otherwise, we could still buy or sell without the mark amongst others if physical money was still currency. This Mark couldn’t be spiritual because the word references two different physical locations. If it was spiritual it would just say in the forehead. RFID microchip implant technology will be the future of a one world cashless society containing digital currency. It will be implanted in the right-hand or the forehead, and we cannot buy or sell without it. Revelation 13:11-18 tells us that a false prophet will arise on the world scene doing miracles before men, deceiving them to receive this Mark. Do not be deceived! We must grow strong in Jesus. AT ALL COSTS, DO NOT TAKE IT!

    “Then a third angel followed them, saying with a loud voice, “If anyone worships the beast and his image, and receives his mark on his forehead or on his hand, he himself shall also drink of the wine of the wrath of God, which is poured out full strength into the cup of His indignation. He shall be tormented with fire and brimstone in the presence of the holy angels and in the presence of the Lamb. And the smoke of their torment ascends forever and ever; and they have no rest day or night, who worship the beast and his image, and whoever receives the mark of his name” (Revelation 14:9-11).

    People have been saying the end is coming for many years, but we needed two key things. One, the Third Temple, and two, the technology for a cashless society to fulfill the prophecy of the Mark of the Beast.

    Visit http://WWW.BIBLEFREEDOM.COM to see proof for these things and why the Bible truly is the word of God!

    If you haven’t already, it is time to seek God with all your heart. Jesus loves you more than you could imagine. He wants to have a relationship with you and redeem you from your sins. Turn to Him and repent while there is still hope! This is forever…God bless!


    We all know God exists. Why? Because without Him, we couldn’t prove anything at all. Do we live our lives as if we cannot know anything? No. So why is God necessary? In order to know anything for certain, you would have to know everything, or have revelation from somebody who does. Who is capable of knowing everything? God. So to know anything, you would have to be God, or know God.

    A worldview without God cannot account for the uniformity and intelligibility of nature. And why is it that we can even reason that God is the best explanation for this if there is no God? We are given reason to know or reject God, but never to know that He does not exist.

    It has been calculated by Roger Penrose that the odds of the initial conditions for the big bang to produce the universe that we see to be a number so big, that we could put a zero on every particle in the universe, and even that would not be enough to use every zero. What are the odds that God created the universe? Odds are no such thing. Who of you would gamble your life on one coin flip?

    Is there evidence that the Bible is the truth? Yes. Did you know that the creation accounts listed in the book of Genesis are not only all correct, but are also in the correct chronological order? That the Bible doesn’t say the Earth was formed in six 24-hour days but rather six long but finite periods of time? That the Bible makes 10 times more creation claims than all major “holy” books combined with no contradictions, while these other books have errors in them? The Bible stood alone by concurring with the big bang saying, “In the beginning God created the heaven and the earth” (Genesis 1:1); and says our universe is expanding, thousands of years before scientists discovered these things. Watch a potential life-changing video on the front page of http://WWW.BIBLEFREEDOM.COM with Astronomer(PhD) Hugh Ross explaining all these facts based on published scientific data. He has authored many books, backed even by atheist scientists.

    Jesus came to pay a debt that we could not; to be our legal justifier to reconcile us back to a Holy God; only if we are willing to receive Him: “For the wages of sin is death…” (Romans 6:23).

    God so loved the world that He gave us His only begotten son, so that whoever believes in Him, through faith, shall not perish, but have everlasting life. Jesus says if we wish to enter into life to keep the commands! The two greatest commands are to love God with all your heart, soul, strength, and mind; and your neighbor as yourself. All the law hang on these commands. We must be born of and lead by the Holy Spirit, to be called children of God, to inherit the kingdom. If we are willing to humble ourselves in prayer to Jesus, to confess and forsake our sins, He is willing to give the Holy Spirit to those who keep asking of Him; giving us a new heart, leading us into all truth!

    Jesus came to free us from the bondage of sin. The everlasting fire was prepared for the devil and his angels due to disobedience to God’s law. If we do the same, what makes us any different than the devil? Jesus says unless we repent, we shall perish. For sin is the transgression of the law. We must walk in the Spirit so we may not fulfill the lusts of the flesh, being hatred, fornication, drunkenness and the like. Whoever practices such things will not inherit the kingdom (Galatians 5:16-26). If we sin, we may come before Jesus to ask for forgiveness (1 John 2:1-2). Evil thoughts are not sins, but rather temptations. It is not until these thoughts conceive and give birth by our own desires that they become sin (James 1:12-15). When we sin, we become in the likeness of the devil’s image, for he who sins is of the devil (1 John 3:8); but if we obey Jesus, in the image of God. For without holiness, we shall not see the Lord (Hebrews 12:14).

    The oldest religion in the world is holiness through faith (James 1:27). What religion did Adam and Eve follow before the fall? Jesus, Who became the last Adam, what religion does He follow? Is He not holy? He never told us to follow the rituals and traditions of man but to take up our cross and follow Him (Luke 9:23). There are many false doctrines being taught leading people astray. This is why we need the Holy Spirit for discernment. Unlike religion, holiness cannot be created. It is given to us from above by the baptism of the Spirit. Jesus is more than a religion; He is about having a personal relationship with the Father. Start by reading the Gospel of Matthew, to hear the words of God, to know His character and commandments. Follow and obey Jesus, for He is the way, the truth, and the life!

Leave a Reply

Your email address will not be published. Required fields are marked *