Steroid and thyroid hormones, Biology

Assignment Help:

Steroid and Thyroid Hormones

Cytoplasmic receptors for steroids are proteins with two subunits that bind to the steroid molecules. When both receptor sites are occupied by the steroid then the receptor-steroid complex migrates to the nucleus where one subunit ensures that the complex binds to the specific site on the chromatin. Then the receptor subunits separate and the other subunit interact directly with the adjacent region of DNA molecule resulting in the transcription of the DNA segment into mRNA.

Thyroid hormone acts in a similar manner except that the receptor is located in the nucleus. The major hormone secreted by thyroid is thyroxine (T4). It travels in blood attached to carrier proteins. Thyroid also secretes a small amount of triiodothyronine (T3). Carrier proteins have higher affinity for T4 and very little T4 is free in the plasma. Only the free T4 and T3 enter the cells. The rest of the bound T4 acts as a reservoir for slow release. The free T4 that enters the cell s also converted to T3 enzymatically. Therefore, T3 is the chemically more potent and active form of thyroid hormone.

552_Steroid and Thyroid Hormones.png

Figure:Steroid and Thyroid Hormones


Related Discussions:- Steroid and thyroid hormones

Selection according to endemic species richness, An alternative approach ha...

An alternative approach has been to identify areas with the highest number of endemics or species with a restricted geographical range. Assessments of this nature have been very of

How is the yolk sac formed, How is the yolk sac formed? What is the functio...

How is the yolk sac formed? What is the function of the yolk sac? The yolk sac is formed from the covering of the vitellus by some cells originated from the primitive gut. T

Define about the micro minerals, Define about the Micro Minerals? Micro...

Define about the Micro Minerals? Micro minerals are those minerals, which comprise less than 0.01% of the total body weight and are required in concentrations of one part per m

Region of the injury in the axial skeleton, what major nerve do you think i...

what major nerve do you think is being compressed when a person often feel pain in the posterior surface of the thigh radiating to the area behind the knee and where is the likely

Why isnt gas exchange done through cutaneous diffusion, In arthropods why i...

In arthropods why isn't gas exchange done through cutaneous diffusion? In arthropods the impermeability of the exoskeleton makes the passage of gases complex. In addition the n

What is the transcription of the gene downstream, A substitution mutation o...

A substitution mutation occurs in the GRE making it unrecongnizable to the glucocorticoid receptor. What impact would this have on the transcription of the gene downstream of this

Explain pea plants in genetics, Explain pea plants in genetics? Pea Pl...

Explain pea plants in genetics? Pea Plants :   In pea plants, sperm are located in the pollen grains produced by the anthers of the flower. Eggs are formed in ovules, structur

What is excessive fat intake, What is Excessive Fat Intake? Although mi...

What is Excessive Fat Intake? Although minimum amount of fat is essential as calculated above but upper limit of fat should be drawn due to its link with an increased risk of d

What is the plasma membrane of the cell, What is the plasma membrane of the...

What is the plasma membrane of the cell? What are its main functions? The plasma membrane is the outer membrane of the cell; it delimits the cell itself and a cell interior wit

What are the symptoms causes of fever, During a fever in a human, A. sh...

During a fever in a human, A. shivering can happen when the actual body temperature is higher than the set point for body temperature during the fever. B. the control system

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd