Natural Hormones
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| Adrenal |
Situated along the perimeter of the adrenal gland, the adrenal cortex mediates the stress response through the production of mineralocorticoids and glucocorticoids, including aldosterone and cortisol respectively.
It is also a secondary site of androgen synthesis. |
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Hormone synthesis All adrenocortical hormones are synthesized from cholesterol. Cholesterol is transported into the inner mitochondrial membrane by steroidogenic acute regulatory protein (STAR), where it is converted into pregnenolone by the enzyme CYP11A1. Accordingly, production of hormones in all three layers of the adrenal cortex is limited by the transportation of cholesterol into the mitochondria and by its conversion into pregnenolone. Pregnenolone can be either dehydrogenated to progesterone, or hydroxylated to 17-alpha-hydroxypregnenolone.
The steps up to this point occur in many steroid-producing tissues. Subsequent steps to generate aldosterone and cortisol, however, primarily occur in the adrenal cortex:
Progesterone → (hydroxylation at C21) → 11-Deoxycorticosterone → (two further hydroxylations at C11 and C18) → Aldosterone
Progesterone → (hydroxylation at C17) → 17-alpha-hydroxyprogesterone → (hydroxylation at C21) → 11-Deoxycortisol → (hydroxylation at C11) → Cortisol
As the production of these hormone products is zone-dependent, so too is the distribution of the key enzymes involved in their synthesis. Aldosterone synthase expression is primarily limited to the glomerulosa while 17alpha-hydroxylase is absent from this layer. As noted above, this enzyme is also absent throughout the cortex of rodents. DHEA synthesis by the human reticularis depends on the absence of 3 beta-hydroxysteroid dehydrogenase.
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| Estrogen |
Estrogens (U.S., otherwise oestrogens or œstrogens) are a group of steroid compounds, named for their importance in the estrous cycle, and functioning as the primary female sex hormone, their name comes from estrus/oistros (period of fertility for female mammals) + gen/gonos = to generate.
Estrogens are used as part of some oral contraceptives, in estrogen replacement therapy for postmenopausal women, and in hormone replacement therapy for transwomen.
Like all steroid hormones, estrogens readily diffuse across the cell membrane. Once inside the cell, they bind to and activate estrogen receptors which in turn up-regulate the expression of many genes.Additionally, estrogens have been shown to activate a G protein-coupled receptor, GPR30. |
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| DHEA |
Dehydroepiandrosterone (DHEA) is an endogenous steroid that has been implicated in a broad range of biological effects in humans and other mammals. Together with its sulfate ester (DHEA-S), it is the most abundant steroid in humans.[citation needed] DHEA is produced by adrenal glands, but also synthesized de novo in the brain. It acts on the androgen receptor both directly and through its metabolites, which include androstenediol and androstenedione, which can undergo further conversion to produce the androgen testosterone and the estrogens estrone and estradiol. DHEA is also a potent sigma-1 agonist. It is
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| GH |
Growth hormone (GH) is a protein-based poly-peptide hormone. It stimulates growth and cell reproduction and regeneration in humans and other animals. It is a 191-amino acid, single-chain polypeptide hormone that is synthesized, stored, and secreted by the somatotroph cells within the lateral wings of the anterior pituitary gland. Somatotropin refers to the growth hormone produced natively and naturally in animals, whereas the term somatropin refers to growth hormone produced by recombinant DNA technology, and is abbreviated "rhGH" in humans.
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| Testosterone |
Testosterone is a steroid hormone from the androgen group. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands. It is the principal male sex hormone and an anabolic steroid.
In men, testosterone plays a key role in health and well-being as well as preventing osteoporosis. On average, an adult human male body produces about forty to sixty times more testosterone than an adult human female body, but females are, from a behavioral perspective (rather than from an anatomical or biological perspective), more sensitive to the hormone. However, the overall ranges for male and female are very wide, such that the ranges actually overlap at the low end and high end respectively.
The stereotype of testosterone as the driver of lust and aggression in men is dismissed by researchers in the field as an over-simplification. |
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| Thyroid |
The thyroid is one of the largest endocrine glands in the body. This gland is found in the neck inferior to (below) the thyroid cartilage (also known as the Adam's apple in men) and at approximately the same level as the cricoid cartilage. The thyroid controls how quickly the body burns energy, makes proteins, and controls how sensitive the body should be to other hormones.
The thyroid participates in these processes by producing thyroid hormones, principally thyroxine (T4) and triiodothyronine (T3). These hormones regulate the rate of metabolism and affect the growth and rate of function of many other systems in the body. Iodine and tyrosine are used to form both T3 and T4.
The thyroid also produces the hormone calcitonin, which plays a role in calcium homeostasis.
The thyroid is controlled by the hypothalamus and pituitary. The gland gets its name from the Greek word for "shield", after the shape of the related thyroid cartilage. Hyperthyroidism (overactive thyroid) and hypothyroidism (under active thyroid) are the most common problems of the thyroid gland. |
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