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

Implementation of nursing care plan, Implementation The planned goals ...

Implementation The planned goals and strategies are translated into nursing intervention by means of the nursing care plan. It is essential that the client and family par

Why does the ingestion of alcohol increase diuresis, Q. Why does the ingest...

Q. Why does the ingestion of alcohol increase diuresis? Alcohol inhibits the secretion of ADH that is antidiuretic hormone by the pituitary that is why when it is drunk to exce

What happens during aerobic respiration to the pyruvic acid, What happens d...

What happens during aerobic respiration to the pyruvic acid molecules made by glycolysis? What is the sequence of reactions that then follows? The pyruvic acid molecules made i

Metamerism or segmentation, Metamerism oe Segmentation In the early c...

Metamerism oe Segmentation In the early coelomates the coelom was not divided into segments, the whole body cavity was a single space. Hence body movements were not precise.

Explain the life cycle of water, Explain the life cycle of Water? The ...

Explain the life cycle of Water? The water cycle , or hydrologic cycle, is one of the most important processes to living organisms on Earth. Consider the following facts:

Determine the cylindrical body of nematodes brought, Compared to platyhelmi...

Compared to platyhelminthes which physiological problem have the cylindrical body of nematodes brought? How was that problem solved? The cylindrical shape of nematodes made imp

Tertiary prevention- preventive strategies for food allergy, Define Tertiar...

Define Tertiary Prevention- preventive strategies for food allergy? Tertiary Prevention: Targets the control of factors that cause symptoms. This strategy would be appropriate

Define the term -aqueous movement and outflow, Define the term -Aqueous Mov...

Define the term -Aqueous Movement and Outflow There are two movements of the aqueous humour that occur-thermal flow and bulk flow. Thermal flow is, an internal circulation of

Which organs are protected by the skull, Which organs are protected by (a) ...

Which organs are protected by (a) the skull, (b) the rib cage, (c) the vertebrae?   a) The skull safe the brain, b) the rib cage safes the heart, lungs, liver and spleen,

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