Gonane

Gonane

0Gonane, also known as perhydrocyclopentanophenanthrene, is the fundamental steroid nucleus consisting of 17 carbon atoms arranged in three rings, without any functional groups or side chains. It is the simplest steroid and the nucleus of all steroids and sterols. Gonane exists as one of two stereoisomers, 5α-gonane and 5β-gonane.

Structure and Nomenclature

The structure of gonane consists of three cyclohexane rings (A, B and C in the diagram) and a cyclopentane ring (D). The junctions of the B/C rings are cis, while the A/B and C/D ring junctions are trans, giving it a decalin structure. The two different arrangements of the hydrogen atoms at C5 lead to two different stereoisomers of gonane, referred to as 5α-gonane and 5β-gonane.

The name "gonane" comes from the Greek root "gonia", meaning angle, which is a reference to the angular structure of the steroid nucleus.

Biological Importance

Gonane is the core structure for all steroids, including corticosteroids, glucocorticoids, mineralocorticoids, progestogens, androgens, estrogens, and progestins. These compounds are critical for a variety of biological functions, including inflammation control, immune response, metabolism regulation, water balance, and reproductive processes.

Synthesis

The biosynthesis of gonane in nature starts with the conversion of squalene to lanosterol by the enzyme squalene epoxidase. Lanosterol is then converted to gonane by the removal of three methyl groups and the reduction of the double bond in the B ring.

See Also

• Steroid
• Steroid hormone
• Steroidogenesis
• Lanosterol
• Squalene