When we say Steroids, our mind unconsciously thinks of the Anabolic steroids used by bodybuilders or weight lifters. We also think them to be just Steroidal Contraceptives for the prevention of pregnancy. However, steroids have a broader definition than just sex hormones or substances used for sports.
Steroids are a class of biological organic compounds that has 4 rings of carbon atoms ( 3 Cyclohexane rings and 1 cyclopentane ring) in a cyclic pattern.
Nevertheless, The four rings (A, B, C, and D) of the asteroid are known as the steroidal nucleus or Gonane. It contains 17 carbon atoms and 28 hydrogen atoms. Because of this configuration, they are hardly soluble in water.
Modification of this gonane by addition, replacement, or substitution with different functional groups can produce different types of steroids that exist in microorganisms, Plants, and Animals.
Synthesis of Steroids
The plant and animal steroids ( Lanosterol and Cycloartenol ) are synthesized via the Mevalonic acid Pathway (MVA). This pathway starts with Acetyl-CoA which is converted to acetoacetyl-CoA by the enzyme Acetoacetyl-CoA thiolase. Further conjugation with another molecule of Acetyl-CoA produces the compound called 3-Hydroxymethylglutaryl-CoA ( HMG-CoA) by the HMG-CoA synthase. This HMG-coA further produces the mevalonic acid with the help of the HMG reductase enzyme – Statins ( Lipid-lowering drugs) acts here.
The Mevalonic acid is split to produce the Isopentenyl Pyrophosphate (IPP) and Dimethylallyl pyrophosphate (DMAPP). The fusion of these two compounds forms Farnesyl Pyrophosphate (FPP). FPP is further converted to Squalene and then to Sterols.
The sterols from squalene produce cycloartenol and lanosterol. The cycloartenol is the building block of all Phytosterols ( plant sterol) while the lanosterol is the precursor to zoosterol (Animal sterols). Examples of Phytosterols from plants are Carotenoids and Phytoestrogen while examples of zoosterols are, Sex hormones, Adrenocortical hormones, Cholesterol, and bile acids.
Types of Steroids
Steroids in animals can exist as a Corticosteroid or Anabolic steroids. These two types of steroids exist as hormones and have a variety of life-saving functions.
The corticosteroids are located in the Adrenal cortex of the kidney and are divided into three; the Mineralocorticoids, the Glucocorticoids, and the sex hormones.
The corticosteroids
Mineralocorticoids e.g., the Aldosterone is responsible for the balance of the electrolytes in the body, especially Sodium and Potassium which helps in the proper functioning of the heart and kidneys. Aldosterone regulates the volume of the blood through excretion and retention of sodium and, therefore, plays a very important role in Hypertension.
Glucocorticoids e.g., Cortisol focuses on the metabolism of glucose. It is usually known as a stress hormone since it can help an individual withstand Stress. Glucocorticoids also help to stop inflammation, hence, the synthetics of glucocorticoids such as hydrocortisone is used to manage Arthritis, Asthma, insect bites, Dermatitis, and Skin rash.
Synthetic corticosteroids such as Prednisolone, hydrocortisone, and cortisone are used in life-threatening issues. They help in the treatment of so many allergic reactions and also suppress the immune system during the transplant of organs. However, long-term use of corticosteroids can cause infections because they tend to suppress the immune system that fights diseases.
Addison’s disease results from insufficient production of the Glucocorticoids and mineralocorticoids. it is a life-threatening disease that can lead to hypertension, low blood sugar, depression, sexual and mood dysfunction e.t.c.
Anabolic steroids
The sex hormones are produced also in small quantities in the adrenal cortex while the bulk of it is from the ovaries and testes. The anabolic is synthetics of the male sex hormone – Testosterone. This hormone regulates so many activities in males. They help in building a strong muscle mass, production of sperm, developing secondary sexual characteristics, and improving in sports.
The anabolic steroids are usually, in cases of Hypogonadism, in some cancers and muscle wasting syndromes. However, it’s likely and easily abused when used indiscriminately for a long term without a doctor’s prescription. Steroid abuse has so many side effects that are very detrimental to health.
Furthermore, another class of steroids known as Steroidal contraceptives is used to prevent unwanted pregnancy. They are the Oestrogen and Progesterone synthetics (sex hormones).
Other steroids
Steroids such as Cardenolides and Bufanolides, also known as Cardiac glycosides are used in medicine to help a failing heart. Carotenoids also found in plants are a rich source of vitamin A for the eye.
The human skin helps manufacture Vitamin D from ultraviolet rays of the sun using 7-dehydrocholesterol which is converted to Cholecalciferol (vitamin D3). Cholecalciferol helps in Calcium reabsorption in the intestine and also deposition of calcium to the bones. The disease called Rickets results from a deficiency of Vitamin D3 which is characterized by softening of bones.
Choleric acids from bile form esters with sulphuric acids, amino acids, or bile alcohols in the intestine and act as fats emulsifiers. Emulsification of fats helps in the absorption of fats you eat and is the work of bile acids.
Finally, the Phytochemistry of some plants proves the presence of a Phytoestrogen. It is a hormone-like compound in plants that can bind to human estrogen receptors and illicit functions similar to estrogen.
