Month: June 2013

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Letrozole is an aromatase inhibitor that may have benefits in managing hormonally-responsive breast cancer in animals. In scientific studies it has been indicated that letrozole may be used for ovarian stimulation because it has fewer side effects than Clomiphene Citrate and fewer changes of causing multiple gestation. Some studies indicate that letrozole may have a lower risk of birth defects in lab rats than chemicals applied for similar purposes.

Studies have also focused on letrozole as a potential option to address gynecomasstia if this disease is in the early stages of treatment, as well as a potential way to manage spermatogenesis.

However, it is important to note that this chemical should not be used outside of a scientific setting and is not yet approved for use on humans or studies on humans.

Influence on Complexation and Hydroxybutenyl-beta Cyclodextrin

• This study worked to examine the in-vitro effects of three various CDs on the chemical letrozole because this chemical is insoluble in water.

• This study indicated that the most promising chemical, hydroxybutenyl-beta cyclodextrin could be used in-vivo in both male and female rats in spite of the fact that letrozole has dramatic gender-based difference when applied as a pharmacokinetic.

• The terminal half-life of the chemical letrozole in male rats is 11.5 while it is 42.3 in female rats.

• Creating a more complex chemical by combining letroxole with the HBenbetaCD helps to improve oral absorption in male rat subjects and helped to maximize the abortion in female rat subjects. In both genders, the presence of HBenbeta CD helped to improve in-vivo rates of absorbtion.

When letrozole was applied in the rat test subjects in capsule form the HBenbetaCD, presence resulted in a higher absolute oral bioavailability. This implies that the solubility limits in the extent and rate of letrozole absorption exist for male rats, but are not limited in the rate of absorption for female rats.

Induced Polycystic Ovaries in the Rat

• This study attempted to develop new models in animals for the study of what’s known as polycystic ovaries by using aromatase inhibitor letrozole(non-steroidal).

• Thirty-four rats were taken as subjects and divided into a control group and three test groups of 10 rats each. Each of these treatment groups were given concentrations of letrozole in .1, .5 and 1 mg respectively. The chemical was administered to the rats once a day for 21 days.

• Throughout the testing period, the rats were collected for vaginal spears and estrus cycle determination. On the subsequent day letrozole administrations, the rats were killed and the ovaries and uteri were weighed and excised while serum hormone levels in the ovaries were examined.

• Compared to the rats in the control group, the ovaries in the study groups had a higher incidence of subcapsular ovarian cysts with capsular thickening with incomplete luteinization. A decreased number of corporea lutea was also seen.

These results are not fully convincing in the study of polycystic ovaries or PCOS. However, this is a vital step in developing an animal model that could be used to study polycystic ovary syndrome in humans without the need for human test subjects.

Letrozole is still in the testing phase. There are no approved doses or applications of this chemical that are approved for use in humans or outside of a research setting.

Sources:

http://www.ncbi.nlm.nih.gov/pubmed/17637172

http://www.ncbi.nlm.nih.gov/pubmed/15010188

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GHRP-6 is a peptide which comprises the AA sequence of H-His-D-Trp-Ala-Trp-D-Phe-Lys-NH2. In studies GHRP-6 has shown biological actions similar to the naturally occurring hunger stimulating peptide ghrelin.

GHRP-6 contains D-amino acids that are entirely synthetic, lacks opioid activity, and shares no sequence relation with GHRH.

It has also been shown that GHRP-6 can lead to re-stimulation of the natural production of GH.

Studies have shown that GHRP-6 increases the secretion of IGF-1 by the liver of some lab rats (Insulin-Like Growth Factor 1), which is speculated to be a required component in the anabolic mechanisms leading to the action of GH. It also appears that GHRP-6 has positive implications for the central nervous system, as ghrelin is known to protect neurons.

What may be the most interesting aspect of ghrelin (and therefore GHRP-6) is the huge variety of roles it plays in biological functions. It is involved in processes in lab rats that include appetite regulation, cardiac functions, gastrointestinal functions, metabolism of carbohydrates, and even has some behavioral effects.

GHRP-6 fills many of ghrelin’s roles, but does not fill all of them. It has been largely shown to focus on the release of GH. Of all synthetic peptides, GHRP-6 is the most ghrelin-like.

When ordering GHRP-6, be sure to choose a research company that:

• Provides MS and HPLC reports on its products.

• Has the ability for large scale production thereby lowering cost and improving efficiency.

• Is committed to customer satisfaction and customer service.

Settle for nothing less than the best in quality peptides.

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(Click here to buy T4 (Levothyroxine) 400 mcg per ml x 30ml in our store)

Levothyroxine is often used in research environments to better understand the treatment options for thyroid hormone deficiency in animals. Some studies have indicated that this chemical may have a future use in helping to prevent reoccurring thyroid cancer in such subjects.

In the past, dextrothyroxine was used to treat conditions such as hypercholesterolemia but levothyroxine is being studied as a potential replacement, as dextrothyroxine is known for causing cardiac side effects in the abovementioned subjects.

Levothyroxine, used in research settings, is typically a synthetic chemical that attempts to mimic the natural secretions which exist in the body. Research is ongoing to better determine the proper way to manufacture these chemicals so they are as accurate as possible when compared to their natural counterparts. This will help both to get accurate results in studies while minimizing side effects in test subjects.

Effects on Maternal Subclinical Hypothyroidism

The study aimed to determine whether maternal subclinical hypothyroidism would impair the spatial learning in the subsequent offspring.

• Wistar female adult rats were divided into six test groups including a control, subclinical hypothyroid, hypothyroid, subclinical hypothyroid treated with levothyroxine. Groups were treated on the 10^th, 13^th or 17 gestational days with a view to restoring what’s called as normal thyroid levels.

• Spatial learning in the offspring was determined by assessing the progenies in a water maze test, a potentiating induction (long term) assay and excitatory postsynaptic potential recording.

• The hypothyroid and subclinical hypothyroid groups showed a longer mean latency in water maze tests as well as a lower amplifaction percentage in the slope and amplitude of the field excitatory postsynaptic potential recording than those in the control group.

Groups that were exposed to levothyroxine saw minimal effects on the offspring’s spatial learning as compared to the control groups. While it was determined that maternal subclinical hypothyroidism would impair the spatial learning of the offspring, treatment early on in the pregnancy could potentially offset this effect.

Levothyroxine in Pregnant Rats with Subclinical Hypothyroidism

The study aimed to investigate how maternal subclinical hypothyroidism would influence a developing brain in subjects and whether levothyroxine has potential as a treatment option for this condition.

• A set of 75 thyroidectomized Wistar female rats were randomly divided into groups that had hypothyroism and were treated with levothyroxine either from the embryonic delay at day 10, 13 17 or post-natal day 21. Fifteen of the rats were sham operated controls.

• The results from the levothyroxine groups showed significantly lower body weights than those in the euthyroid groups. Those from the groups treated at day 10, 13 and 17 showed a normal body weight compared to the other groups. Latencies in these groups were longer than those in the controls.

• The barrel cortex of those in the day 10 and 13 groups was very similar to the control group. Distributions of the hypothyroid groups and those treated at day 17 saw a more widespread level of bromodeoxyuridinelabeled cells than those in the other groups.

These conclusions indicate that the maternal presence of hypothyroidism will affect memory and learning in the offspring. However, treating with levothyroxine early in the pregnancy may help to prevent these cells from migrating to the brain where they can cause such damage.

Currently, levothyroxine is not approved for use in humans or study on humans. Dosages and official usage information is not available.

Sources:

http://www.ncbi.nlm.nih.gov/pubmed/22192600

http://www.ncbi.nlm.nih.gov/pubmed/22024639

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