Oestrogens
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There are a number of sources of estrogens produced in the body
- They are produced from the granulose cells of the follicle, the corpus luteum of primates, the placenta the adrenals and the testes.
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Oestrogens influence the female sex characteristics such as an increase in the growth, protein synthesis and fluid secretions of oviduct, uterus, cervix and vagina.
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They also affect mammary development.
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They induce the expression of behavioural estrus in the female and libido in the male.
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Oestrogens also have many effects on general body metabolism including fat distribution and content within the body, mineral metabolism, bone growth and protein synthesis in may tissues including the muscle.
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They influence gonadotrophin secretion and at low concentrations have a negative feed back effect on the hypothalamus, while at high doses, in the absence of progesterone they have a positive feed back effect in females resulting in the preovulatory surge in gonadotrophin output.
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The testes of both the boar and the stallion produce oestrogens in high quantities and pregnant mares produce a wide range of estrogens like equilin, hippulin and equilenin.
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Equine male urine and testes contain enormous quantities of estrogens.
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The natural estrogens include 17 beta - estradiol, estrone and estriol.
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They have low oral activity.
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Synthetic steroidal estrogens include simple esters such as estradiol benzoate or valerate.
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The most common non-steroidal estrogens, which have a high affinity for the estradiol receptor, are the stilbenes.
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They are orally active, highly potent and are not easily metabolized.
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Some are genotoxic carcinogens and hence their use is prohibited.
Clinical uses
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Misalliance in the bitch
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Induction of oestrus and ovulation in anoestrus animals
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Control of the time of ovulation
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Control of life-span of the corpus luteum
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Treatment of pyometra and mummified foetus
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Obesity due to hypogonadism in bitches
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Urinary incontinence in old and spayed bitches
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Anal oedema in dogs
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Regression of hypertrophied prostrate glands
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Caponization of young and old cockerels
Side effects
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This includes gastrointestinal upsets, feminization in male, sodium retention and oedema.
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In chronic overdosage genital erythema, irritation, polydipsia and polyuria are noticed.
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Last modified: Thursday, 26 April 2012, 5:14 AM