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

Annelids - hormones in growth and reproduction, Annelids - Hormones in Grow...

Annelids - Hormones in Growth and Reproduction Studies on polychaetes have displayed that the endocrine glands play a key role in growth and reproduction. In addition to the b

Increase in the divcat conductance of neuron b, Consider Neuron B in the fr...

Consider Neuron B in the frog central nervous system whose plasma membrane has a previously unknown channel that is selectively conductive to a newly discovered divalent cation nam

Phosphate group, Shift of the phosphate group from carbon 3 to carbon 2 ...

Shift of the phosphate group from carbon 3 to carbon 2 Shift of thephosphate group form carbon 3 to carbon 2: This reversible reaction is  catalyzed by phosphoglycerate mutas

Nutrient budgets - nutrient cycles, Nutrient Budgets - Nutrient Cycles ...

Nutrient Budgets - Nutrient Cycles Nutrients are constantly being added and removed by natural and artificial processes. The measure of the input and outflow of nutrients thro

Advantages of fertilizers and manures, Advantages of Fertilizers and manure...

Advantages of Fertilizers and manures Fertilizers and manures are necessary for maintaining the soil in a high state of fertility and productivity.  It is important to know the

How to investigate aortic stenosis by electrocardiogram, Q. How to investig...

Q. How to investigate aortic stenosis by Electrocardiogram? Typically left ventricular hypertrophy with strain pattern is seen in severe aortic stenosis. Total QRS amplitude in

Common disorders of coronary heart diseases, Q. Common Disorders of Coronar...

Q. Common Disorders of Coronary Heart Diseases? We shall deal with different types of heart diseases, their- etiology, symptoms, complications, as well as, nutrition and dietar

Define the viscosity of protein, Define the Viscosity of Protein? Visco...

Define the Viscosity of Protein? Viscosity reflects resistance to flow. The main single factor influencing the viscosity behavior of protein fluids is the apparent diameter of

Pollution, Phosphate detergent as cause of water pollution

Phosphate detergent as cause of water pollution

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