Parathyroid Hormone

Comic strip made by BHIE-LOGGER

Bones are not only helpful in wooing girls, but also in every activity that we do. Calcium is always associated when we talk about bones. We often heard the word ‘calcium' in many milk product commercials. It is one of the minerals that help in the bone matrix formation. But how is the calcium absorbed by the body? What is the principal hormone that is responsible for regulating such minerals?

The endocrine gland in focus is the PARATHYROID GLAND. Better watch this video clip to have a glimpse on this gland's role in our body.

Video made by dizzo95 and shared by youtube.com

Parathyroid gland is located behind of our thyroid gland. It is considered to be the ‘small but terrible' gland because it secretes the hormone that makes our bones stronger and maintains certain minerals inside our body. This hormone is called the parathyroid hormone (also called as PTH, parathormone or parathyrin) that is considered to be a polypeptide, consisting of 84 amino acids.

There are many job descriptions of PTH. All of which is connected to the bone matrix formation and regulation of mineral levels in the blood.

1. Monitoring of Serum Calcium Levels. Bones, kidneys and intestines are the target tissues of the PTH in relation to the regulation of serum calcium.

Photo by Wikipedia.org

In the bones, calcium is released by the PTH by indirect stimulation. The process involved is called bone resorption. It is the bone destruction by the osteoclast, in which it is indirectly enhanced by the PTH.

In kidneys, it is an opposite way. Calcium is reabsorbed from the distal tubules and ascending limb. It is reabsorbed together with the magnesium.

There is also absorption of calcium in the intestines. PTH absorbed calcium by elevating the activated Vitamin D. PTH stimulates enzyme that converts Vitamin D into its activated form in the kidneys. This enzyme will eventually increase the calcium reabsorption in the intestine with the help of a protein called calbindin.

2. Monitoring the Serum Phosphate. Oppose to that of calcium, the PTH reduces the phosphate reabsorption in the kidneys, specifically at the proximal tubules. The release of phosphate from the bone is slightly lower than the calcium. Activated vitamin D also helps in the phosphate reabsorption, though calcium is more dependent on vitamin D compared to the phosphate.

3. Vitamin D activation. As I have said earlier, vitamin D has an important role in the calcium and phosphate reabsorption. The question is, how is PTH activates the vitamin D in our body? PTH controls the 25-hydroxyvitamin D3 1-alpha-hydroxylase, which is the enzyme that converts vitamin D into its activated form. The activated form of vitamin D is called 1,25-dihydroxycholecalciferol, also called as calcitriol.

The parathyroid gland releases PTH in accordance with the low concentration of calcium. There will be a sudden elevation of PTH if the serum calcium is below normal. But even if the serum calcium is high, still there is a low secretion of PTH.

See how those 'small but terrible' glands are helpful in our lives. At first, we don't mind if these glands exist or not, but now we already know its functions. We should appreciate and be thankful for every glands that God had given to us.

REFERENCES:
Clinical Chemistry: A Fundamental Textbook by Donald Calbreath
http://en.wikipedia.org/wiki/Parathyroid_hormone
http://parathyroid.com/parathyroid-function.htm

Clinical Chemistry 3: An Introduction

Similar to movies and bestseller books, Clinical Chemistry is a TRILOGY subject. CC 01 is all about Routine Clinical Chemistry; CC 02 is about Special Chemistry; and lastly, CC 03 is about Endocrinology, Toxicology and Drug Testing. As they always say, the LAST part is the BEST but the BLOODIEST.

This blog is all about Clinical Chemistry 3. And for a jump start, lets define the aforementioned terms that are included in the subject.

ENDOCRINOLOGY

When people hear the word endocrinologist, they simply say that they are doctors which specialize with hormonal imbalances. Endocrinology is basically the study endocrine system, which is composed of glands that secretes hormones. It includes processes of production, their functions, and also their correlated diseases. Hormones are the principal area under discussion of this field of science.

TOXICOLOGY

Our generation is now surrounded by chemicals which can be either helpful or harmful. Chemicals are always associated with health threats. That’s why chemical hazard sign is labelled with a skull signifying danger or death. Toxicology is simply the study of the chemicals which have adverse effects to human beings. This field of science measures the risks and circumstances of these harmful chemical ranging from short to long term results.

DRUG TESTING

Cocaine, marijuana and heroin – these are some of the abused substances that had gain many issues and law-related violations in our generation. These had caused many individuals to lose their track in life, destroyed many families, and even brought disarray to our community. Usually, drug testing is very helpful to combat drug usage. Drug testing is a way to determine people who had taken specified drugs or substances. It can even quantify the amount of taken substances. This test usually includes many biological specimens like blood, urine, saliva, sweat and even hair.

REFERENCES:
Clinical Chemistry: A Fundamental Textbook by Donald Calbreath