Month: August 2013

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Leuprorelin acetate is a GnRH sequence that acts as an antagonist for pituitary GnRH receptors in animals. Using this to interrupt the regular pulsatile of this chemical desensitizes GnRH receptors, to down-regulate the gonadotropins of LH and FSH. This will lead to hypogonadism which will dramatically reduce testosterone and estradiol.

Research of leuprorelin acetate typically revolves around its potential use in managing hormone responsive cancers such as breast or prostate cancer as well as conditions that are dependent on estrogen such as endometriosis. Some research indicates that leuprorelin may have use in managing precocious puberty or controlling the stimulation of the ovaries. Some research has looked into the potential for using leuprorelin acetate to reduce sexual urges as displayed by pedophiles or sex offenders.

Non-sexual research into leuprorelin includes the potential management of Alzheimer’s disease. Research involving ferrets has implied that chronic adrenal disease could also be managed by administering leuprorelin acetate. Some research focuses on the potential to use leuprorelin acetate as a means to manage autism, but this was based on the assumption that testosterone or mercury played a hand in developing this disease, which has been revealed to be untrue.

Injectable Microspheres

Biodegradable polymers were used to contain LH-RH superantagonist (leuprorelin acetate) in an experimental environment.

• A W/O/W emulsion solvent evaporation was used to aid in the preparation of the msp. This contained a water soluble peptide to achieve high efficiency of the entrapment and help to sustain the drug release over a predominantly thanks to a polymer bio-erosion.
• The msp was found in microcapsules along with polycores that contain the high concentrations of leuprorelin so they would be easy to apply via injection to the animals used in the study.

Leuprporelin was applied to persistently suppress the gonadal pituitary system for 1-3 months. Results of these actions indicated that these formulations may be helpful in therapy for the endocrine system, particularly in treating such diseases in humans.

Sustained Suppression of Pituitary Gonadal Axis

During this study researchers hoped to develop a depot system for leuprolide acetate based on an existing drug delivery system in order to suppress the pituitary gonadal axis to transform the serum of testosterone to a chemical castration level for 3 months.

• Biodegradable forms of the peptide were formulated by molecular weight and hydropilicity in rats and were rates for the efficacy of measuring this system by testosterone levels.
• Initial studies in rats indicated that a formulation that contained a 75/25 ratio of lactide/glycolide with leuprolide acetate could suppress serum testosterone for over three months.

This formulation has high biocompatibility, biogradability and is easy to apply which may prove beneficial in using this formula to better manage cancers and other diseases that are controlled or increased by the presence of testosterone.

Leuprorelin acetate for research is largely designed to be applied to animal test subjects via injection every 3-4 months. Vials are available in a variety of sizes based on what type of animal will be exposed to this chemical and the nature of the research that will be applied.

Sources:

http://www.sciencedirect.com/science/article/pii/S0169409X97000501
http://onlinelibrary.wiley.com/doi/10.1002/%28SICI%291520-6017%28200006%2989:6%3C732::AID-JPS4%3E3.0.CO;2-D/abstract?deniedAccessCustomisedMessage=&userIsAuthenticated=false

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Ornipressin acetate may act as a haemostatic, vasoconstrictor and renal agent. This is a general term for the synthetic version for the natural chemical vasopressin which is produced in the body. The synthetic version of this chemical has an ornithine in the eighth position of the cyclic octapeptide chain. Much of the research regarding potential uses or understanding of the chemical is ongoing.

When purchasing ornipressin for research purposes it is vital to invest in a pure sample. Because there are many chemicals similar to ornipressin acetate on the market it can be difficult to determine if you are purchasing a sample that will behave the way you have hoped during clinical research.

Purchasing from a licensed dealer can help to ensure that you receive the proper chemical for your research as well as a sample that is sure to be pure to help guarantee accurate results during testing.

Effects on Lignocaine Nerve Blocks

Using an electrophysiogical method of measuring the conduction of nerves after an electrical stimulation of the sciatic nerve branches, anaesthetized rats were evaluated under controlled conditions to determine the effects of ornipressin on the system.

Factors compared included the duration of the lignocaine anesthesia as well as the speed of onset.

Research determined that compared to lignocaine on its own, lignocaine combined with ornipressin during applications would produce shorter onsets of anesthesia with an improved duration and depth.

During the adrenaline exposure to lignocaine this simple extended the action of the chemical while ornipressin, even at very low concentrations during application produced satisfactory results. This implies that ornipressin may be considered a satisfactory vasoconductor for adrenaline, though this may still produce undesirable results in some candidates.

Effects on Ovariectomized Rats in Vivo

Over a two week period of oral raloxifene therapy on nitric oxide at the cardio level, ovariectomized rats were monitored for the susceptibility of the angina.

This ovariectomy caused a decrease in the nitric oxide synthase activity following this application and again after an application of phentolamine. After reloxifene was applied these effects were reversed.

The ST segment depression was augmented in the rats and this abolished the anti-ischaemic effects following the raloxifene.

Oestrogen deficiency can down regulate cardiac constitutive nitric oxide synthase that can increase the heart’s susceptibility to ishaemia. Both of these actions can be prevented using exogenous administration of a natural oestrogen product or by applying a selective oestrogen-receptor modulator such as raloxfiene in vivo as raloxifene exerts the oestrogen antagonist properties.

In order to keep samples of ornipressin acetate pure during long-term testing all instructions on the container should be followed explicitly. Keep this chemical in a sealed container and take care when storing the chemical to ensure that it is not being exposed to extreme temperatures that can cause the peptide to break down more quickly.

Avoid freezing and re-thawing the peptide repetitively if you will be using it for multiple experiments that will take long periods of time as this will also work to break down the peptide more quickly, which may alter its performance.

Sources:

http://onlinelibrary.wiley.com/doi/10.1111/j.1399-6576.1986.tb02493.x/abstract?deniedAccessCustomisedMessage=&userIsAuthenticated=false
http://www.sciencedirect.com/science/article/pii/S0014299904005588

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This is a hormone that helps the body to manage the endocrine system by impacting cell proliferation and neurotransmission by interacting with somatostatin receptors (G protein-coupled) to inhibit the release of secondary hormones throughout the body.

There are two active forms that are often produced by preproprotein, one containing 28 amino acids and one that contains 14 amono acids. Vertebrates have six different genes that participate in somostatin production, allowing it to perform a variety of functions depending on the animal in which it is displayed.

Somatostatin may be produced in an animal’s digestive system to encourage acid producing parietal cells while decreasing production of histamine, gastrin and secretin. It is also present in the gastrointestinal system to stop the release of overactive gastrointestinal hormones to suppress pancreatic hormones or decrease the rate in which the gastric system empties while improving blood flow to the intestines.

This is classified as an inhibitory hormone which can be spread to many other areas of the body in an animal, particularly in inhibiting the release of thyroid stimulating hormone.

Preparing Somatostatin

Somatostatin is used in therapeutic peptide applications that have become entrapped in polymeric microspheres from a molecular weight with a variety of modifications using an O/W solvent evaporation method.

This chemical can be dispersed in a solid or dissolved at the aid of the co-solvent or it can be emulsified and dissolved into a co-solvent. It may also be emulsified within an aqueous solution with an organic polymer solution.
Encapsulation efficiencies can be obtained with all of these methods regardless of the polymer type used or the state of the chemical once it has begun.

In more cases lipophilic solvent systems can be used to favor an efficient drug encapsulation. This has largely been replacing toxic methylene chloride lower drug loadings and has affected the morphology of this chemical release.

Inhibition of Experimental Angiogenesis

A study has investigated the effects of somatostatin on experimental angiogenesis in vivo and in vitro.

It was found that applying octreotide reduced the proliferation of endothelial cells while the density of this vascular network would chick chorioallantoic membranes.

The proliferation of endothelial and smooth muscle cells in the rat aorta were reduced by octerotide. A similar cell sprout was seen in the fibrin cells.

Topical administration of the octerotide was inhibited rat cornea neovascularization that was induced by these controls. This could be used as an angiogenesis for rat mesentery in mast cells deregulating agents. These chemicals may also be able to reduce neovascularization tendencies, compared to traditional controls. This implies that octerotide may be more effective in managing these conditions than somatostatin.

Within the brain somatostatin is produced by neuroendocrine neurons in the hypothalamus where it is then released in the hypthalamo-hypophysial system and carried through the anterior pituitary gland.

Sources:

http://clincancerres.aacrjournals.org/content/3/2/265.short
http://www.sciencedirect.com/science/article/pii/S0939641197001252

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Click here to view/download the PDF version of this article