steroid

(noun)

a class of organic compounds having a structure of 17 carbon atoms arranged in four rings; they are lipids, and occur naturally as sterols, bile acids, adrenal and sex hormones, and some vitamins

Related Terms

Examples of steroid in the following topics:

  • Steroids

    • Unlike phospholipids and fats, steroids have a fused ring structure.
    • Many steroids also have the –OH functional group, and these steroids are classified as alcohols called sterols.
    • Therefore, steroids play very important roles in the body's reproductive system.
    • Thus, steroids also play an important role in the structure and function of membranes.
    • Steroids, such as cholesterol and cortisol, are composed of four fused hydrocarbon rings.

  • Signaling Molecules

    • Important members of this class of ligands are the steroid hormones.
    • Steroids are lipids that have a hydrocarbon skeleton with four fused rings; different steroids have different functional groups attached to the carbon skeleton.
    • Steroid hormones include the female sex hormone, estradiol, which is a type of estrogen; the male sex hormone, testosterone; and cholesterol, which is an important structural component of biological membranes and a precursor of steriod hormones .
    • Steroid hormones have similar chemical structures to their precursor, cholesterol.

  • Lipid-Derived, Amino Acid-Derived, and Peptide Hormones

    • The primary class of lipid hormones in humans is the steroid hormones.
    • Examples of steroid hormones include estradiol, which is an estrogen, or female sex hormone, and testosterone, which is an androgen, or male sex hormone.
    • Other steroid hormones include aldosterone and cortisol, which are released by the adrenal glands along with some other types of androgens.
    • Steroid hormones are insoluble in water; they are carried by transport proteins in blood.
    • The structures shown here represent (a) cholesterol, plus the steroid hormones (b) testosterone and (c) estradiol.

  • Intracellular Hormone Receptors

    • Lipid-derived (soluble) hormones such as steroid hormones diffuse across the lipid bilayer membranes of the endocrine cell.
    • The cell signaling pathways induced by the steroid hormones regulate specific genes within the cell's DNA.
    • In this way, the steroid hormone regulates specific cell processes .
    • Other lipid-soluble hormones that are not steroid hormones, such as vitamin D and thyroxine, have receptors located in the nucleus.
    • The hormone-receptor complex stimulates transcription of specific genes in the same way that steroid hormones do.

  • Plant Defenses Against Herbivores

    • Foxgloves produce several deadly chemicals, namely cardiac and steroidal glycosides.
    • Foxgloves produce several deadly chemicals, namely cardiac and steroidal glycosides.

  • Connecting Lipids to Glucose Metabolism

    • Cholesterol contributes to cell membrane flexibility and is a precursor to steroid hormones.

  • The Endoplasmic Reticulum

    • Functions of the SER include synthesis of carbohydrates, lipids, and steroid hormones; detoxification of medications and poisons; and storage of calcium ions.

  • Zygomycota: The Conjugated Fungi

    • The metabolic products of other species of Rhizopus are intermediates in the synthesis of semi-synthetic steroid hormones.

  • Pineal Gland and Gonads

    • Their main role is the production of steroid hormones.

  • Plasma Membrane Hormone Receptors

    • Unlike steroid hormones, lipid-insoluble hormones do not directly affect the target cell because they cannot enter the cell and act directly on DNA.