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

Define changes in food due to concentration process, Define Changes in Food...

Define Changes in Food due to Concentration Process? Obviously concentration that exposes food to 100°C or higher temperatures for prolonged periods can cause major changes in

Osmoregulation in freshwater metazoans, Osmoregulation in Freshwater Metazo...

Osmoregulation in Freshwater Metazoans Freshwater and brackish water animals that are live in hypoosmotic(of lower osmotic pressure) environment and keep a hyperosmotic (of h

Lungs, what''s the role of lungs in terms of excretion? Like the trachea wh...

what''s the role of lungs in terms of excretion? Like the trachea what''s its role in excretory system?

Genetics, what is a homologous chromosome

what is a homologous chromosome

Biological species concept, The biologicaI species concept claims that spec...

The biologicaI species concept claims that species consist of natural populations and that species are real and objective. They are not man-made subjective abstraction. According

Risk management option assessment, Risk management option assessment : ...

Risk management option assessment : Identification of available management options Selection of preferred management option , including consideration of an appropriate saf

Poverty and malnutrition, Poverty and Malnutrition Poverty and malnutr...

Poverty and Malnutrition Poverty and malnutrition are closely related. As noted before, many elementary aspects of being poor like hunger, inadequate health care, unhygienic l

Pathphysiology of rheumatic fever, Pathphysiology Streptococcal upper ...

Pathphysiology Streptococcal upper respiratory infection leads to production of antibodies. An abnormal immunological response to the upper respiratory infection with Beta- h

Explain how a cell produces and releases proteins, Explain how a cell produ...

Explain how a cell produces and releases proteins. Proteins are made on ribosomes and packaged into vesicles by the Golgi apparatus. The vesicles move to the cell membrane and

Preservation of species diversity, Q. Preservation of species diversity? ...

Q. Preservation of species diversity? Genetic diversity is, thus, important for the preservation of species diversity, and hence biological diversity. A knowledge of the variab

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