Contact US
Address: South Time 16 building 1 Unit Room 1102 Nansha, Guangzhou, Guangdong
TEL: 86-20-28125195
FAX : 86-20-28125195
Home > Exhibition > Content
HORMONES | Steroid Hormones
- May 15, 2018 -

Introduction

Steroid hormones are well known both physiologically and clinically as regulators of diverse biological responses, including profound effects on cellular metabolism, development, and physiology. The steroid hormones are the estrogens (female sex steroids), androgens (male sex steroids), progestins, mineralocorticoids, glucocorticoids, and vitamin D with its daughter metabolites.

All these different steroid hormones are synthesized from the common precursor, cholesterol, and structurally differ only in the pattern of chemical bonds within the rings and modifications on the side chain. The exquisite specificity of physiological effects that these steroid hormones evoke is mediated by high-affinity intracellular receptor proteins that are exclusively localized in the specific target tissues for each steroid hormone. Specific interaction of the hormone–receptor complex with DNA sequences of the hormone-responsive gene(s) results in the tissue-specific expression of proteins which either directly or indirectly generate the biological responses attributable to the steroid hormones. The application of cellular and molecular biological techniques has allowed greater understanding of the way in which such small molecules exert diverse biological effects with exquisite specificity.

Steroid hormones are measured clinically in different matrices including serum, plasma, and urine. Testosterone, free testosterone, estradiol, free estradiol, estrone, estriol, DHEA, DHEAS, progesterone, 17-hydroxyprogesterone, 17-hydroxypregnenolone, 11-deoxycorticosterone, 11-deoxycortisol, and androstenedione are measured in serum or plasma. Aldosterone and cortisol are measured in serum, plasma, and urine.

It is important to document acceptable tube types for each analyte, the time the sample should be collected, and how the sample should be stored so that the analyte remains stable (see Sections 7.2, 7.5, and 7.6). There are also other preanalytical variables that also have to be taken into account for the steroid hormones (see Sections 7.3 and 7.4 later).


Steroid hormones are derived from cholesterol. Consequently, steroid hormones are generally poorly soluble in water and, following secretion, are transported bound to plasma-binding proteins. Steroids diffuse across the plasma membrane and bind to a cytoplasmic binding protein. The steroid—binding protein complex diffuses to the nucleus and activates a hormone response element, which initiates DNA transcription and translation. The reliance on DNA transcription and translation means that steroid hormones generally have a long lag time between secretion and effect. Some steroids, like aldosterone and estrogen, can produce acute effects independent of any nuclear effects. This allows such hormones to have both acute and chronic actions.


Steroid hormones are derived from a common precursor molecule, cholesterol, via the metabolic pathway schematically outlined in Figure 21-1. More than 1500 biologically active steroids have been isolated from biological material or have been produced synthetically. The molecular weight of steroid hormones is low, usually below 500 (Table 21-1). Examples of steroids that play an important role in reproductive processes are estrogens, androgens, and progestagens, with the main source being the gonads. The structure of the most important sex steroids is presented in Figure 21-2. The most common steroid hormones are usually designated by a trivial name (e.g., estradiol, testosterone, or progesterone). The International Union of Pure and Applied Chemistry (IUPAC; www.iupac.org) has recommended systemic names for steroid hormones. These systemic names describe the chemical and stereoisomeric characteristics of the particular steroid hormone (Table 21-1).