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Oestrous Cycle Pharmacological Manipulation - Anatomy & Physiology (view source)
Revision as of 11:41, 12 September 2008
, 11:41, 12 September 2008→Pharmacological: Synthetic Progestagens
=== Pharmacological: Progesterone ===
=== Pharmacological: Progesterone ===
=== Pharmacological: Synthetic Progestagens ===
=== Pharmacological: Synthetic Progestogens ===
* Used to suppress oestrus.
* Commonly used progestogens include:
** Megoestrol acetate
** Proligestone
** Medroxyprogesterone
* These are available orally or for injection.
* They can be used to postpone the onset of oestrus when administered during anoestrus.
** Can be postponed for up to a year by injecting progestogens at intervals of 3-5 months or giving a 40 day course of oral tablets twice a week.
* Another use is to prevent oestrus from occuring if administered at the fist signs of pro-oestrus.
** This is achieved by a single injection or oral progestogen at a higher dose rate than for postmonement, but for a shorter duration.
* Following administration of progestogens, the interval before onset of the next oestrus is unpredictable if treatment is not continued.
* Frequent use can predispose the bitch to reproductive disorders, particularly cystic glandular hyperplasia of the endometrium.
* First generation progestogens such as Medroxyprogesterone acetate (MPA) carry the risk of stimulating growth hormone (GH) secretion. This leads to an increased risk of acromegaly, mammary tumours and diabetes mellitus.
==== Proligestone (PRG) ====
==== Proligestone (PRG) ====
* A new drug specifically designed to prevent oestrus in bitches and queens.
* It is particularly suitable because:
** Strongly anti-gonadotrophic
** Weakly progestagenic
** Antioestrogenic, so effectively controls vulval swelling and bleeding.
=== Pharmacological: Testosterone ===
=== Pharmacological: Testosterone ===