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

Bio212, do you think the social and cultural environment of the 18th and 19...

do you think the social and cultural environment of the 18th and 19th centuries helped or hindered the study of microbiology in particular and science in general

Isospora, ciclo vital de la isospora belli

ciclo vital de la isospora belli

Theory or principle of determination of the quality of milk, Explain the Th...

Explain the Theory or Principle of Determination of the Quality of Milk Milk is an ideal medium for the survival and growth of microorganisms. It contain all the nutrients, i.e

Lithosphere, The lithosphere contains all of the hard solid land of the ear...

The lithosphere contains all of the hard solid land of the earth crust and the semisolid land underneath the crust. The surface of the lithosphere is very uneven contains high moun

Define larval stage of taenia cystcercus, Define Larval Stage of Taenia Cys...

Define Larval Stage of Taenia Cystcercus? The pork tapeworn (T: solium) and beef tapeworn (T : saginata , which are endoparasites of humans who are the final hosts

Malthus theory of human population growth, MA L THU S THEORY OF HUMAN PO...

MA L THU S THEORY OF HUMAN POPULATION GROWTH - Malthus put forward in 1778. 1.       Population grows in geometrical ratio, where as the means grow in arithmetical ratio.

Overgrazing - degradation of ecosystem, Overgrazing - Degradation of Ecosys...

Overgrazing - Degradation of Ecosystem It refers to the condition when the grazing pressure on the vegetation is so intense that it does not recover. Ultimately, there is a lo

Explain theory of enzyme action, Explain Theory of enzyme action L. Mic...

Explain Theory of enzyme action L. Michaelis  and k L. Menten developed a general  theory of enzyme action and kinetics  in  1913. According to this theory, we learnt  that

Female reproductive system, FEMALE REPRODUCTIVE SYSTEM - In female mamm...

FEMALE REPRODUCTIVE SYSTEM - In female mammals the female reproductive system characteristically comprises of the ovary, uterus, placenta, vagina and vulva.

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