Steroids are known to occur in more than one manifestation, as well as in different categories. Some of these categories include animal steroids, plant steroids and fungus steroids. This means that steroids are manifested in natural ecosystems as well as occurring as chemical compounds in natural substances.
These categories are also known as functional categories, as well taxonomic characterization of steroids in the sphere of occurrence, depicted by the animals, plants and fungus components.

Animal steroids

Animal steroids occur in different unique categories characterized by Insect steroids and Vertebrate steroids.

Insect steroids

Insect steroids occur in a substance characterized by Ecdystereroid which shows itself forthwith in ecdsterone hormone.

It is in Vertebrate steroids that the functional importance as well as occurrence of steroids is obtrusive. These categories include steroid hormones which make up a large chunk of the vertebrate steroids. In essence, these hormones include sex steroids, which happen to be a subset of sex hormones which also produce sex differences referred to as support reproduction in different circles. These hormones include estrogens, progestagens as well as androgens.
On the other hand, corticosteroids also occur as vertebrate steroids which include mineral corticoids as well as gluco-corticoids.

Mineral corticoids have a function of maintaining the blood volume as well as controlling the renal excretion of the chemical electrolytes. Gluco-corticoids have the important function of regulating the many aspects of
immune functions and also the metabolism of the body.

Anabolic steroids are also another functional category of vertebrate steroids that happen to bring about the interaction of androgen receptors in the instance of increasing bone and muscle synthesis in the body of a steroid user. In fact in popular terms, 'steroids' is a word that is mostly used to refer to these anabolic steroids when referring to general steroids.

Cholesterol is another type of vertebrate steroids which helps in the modulation of the fluidity that occurs in cell membranes as well as being the important principle constituent of most plaques that are implicated in the process of atherosclerosis.

In plant steroids the occurrence is manifested mostly in phytosterols and the substance Brassinosteroids that are elements in the composition of plants containing them.

In fungus steroids, the manifestation of steroids is mostly in Ergosterols.
All in all, steroids have been known to vary by these functional groups which are chemically attached the rings of the compounds as well as in the oxidation form of the steroid rings. All steroids have been found to be made in the cell domain from what is called the sterol lanosterol in animals as well as in fungi or similarly in sterol cyclo-artenol which is specific in plants. These two sterols are a derivative of process of cyclization of the component triterpene squalene.

Some neurons that are found in the central nervous systems have a function that is requires neuro-steroids to be synthesized which takes place in the periphery of some derived sources. Lastly, the rate that limits the synthesis of steroids is when cholesterol is being converted to pregnenolone which takes place inside a mitochondrion.