Tuesday, January 9, 2018

Amino Acids, Growth Hormone, Oxidative Phosphorylation, and Symptomatic PSSM Horses

Here is some miscellaneous info and links that I've found interesting.  I'm posting them, partially so I'll review them again later, and partially for anyone who may also find this information helpful.  As always, be careful when trying diet changes, supplements, etc. with these sensitive horses.

Arginine, Asparctic Acid, and Glutamic Acid are all amino acids that help release growth hormone.

Pituitary hormone and insulin responses to infusion of amino acids and N-methyl-D,L-aspartate in horses.
"...In the horse, aspartic acid, glutamic acid, and NMA seem to stimulate GH release; arginine and lysine seem to stimulate prolactin and insulin release; and NMA seems to stimulate LH and FSH release. It seems that N-methyl-D-aspartate glutamate receptors are involved in controlling GH, LH, and FSH secretion, whereas other mechanisms are involved with prolactin secretion. These results also indicate that gonadal steroids interact with amino acid-induced pituitary hormone release in adult horses..."

"...The disruption of GHR in skeletal muscle and the consequent histomorphometric changes in myofiber type and size and myonuclei number result in functionally impaired skeletal muscle. In agreement with these effects, the histology of muscles of untreated GHD patients is strongly altered, and glucose and triglyceride uptake and metabolism in skeletal muscle of GHR mutant mice are affected..."

Regulation of mitochondrial oxidative phosphorylation through cell signaling
"The mitochondrial oxidative phosphorylation (OxPhos) system plays a key role in energy production, the generation of free radicals, and apoptosis. A lack of cellular energy, excessive radical production, and dysregulated apoptosis are found alone or in combination in most human diseases, including neurodegenerative diseases, stroke, cardiovascular disorders, ischemia/reperfusion, and cancer..."

Here's a couple more articles related to growth hormone, glutamine, and asparctic acid:
Only the last link pertains to horses, the others are on humans and mice. Some of the growth hormone info may point to why studs seem more likely to be asymptomatic.  

Here are a couple of articles pertaining to arginine, the 1st one is particularly interesting for horses suffering from IR, and the insulin/arginine issue may only pertain to mares (see the 4th link):

"...The link between excessive muscle glycogen, abnormal polysaccharide and rhabdomyolysis during sub-maximal exercise is less clear. To evaluate the changes in muscle that lead to this energy deficit, muscle gene expression profiles before and after a controlled exercise trial were evaluated in PSSM1 cases and controls by RNASeq... Gene set enrichment analysis revealed enrichment in pathways involving mitochondria biogenesis, oxidative phosphorylation, fatty acid metabolism, glycogen and glucose metabolism..."

"...In the PSSM muscles, histological data revealed PAS positive amylase resistant abnormal polysaccharides, inflammation, necrosis, and lipomatosis and active regeneration of fibers. Ultrastructural evaluation revealed a decrease of mitochondrial number and structural disorders. Extensive accumulation of an abnormal polysaccharide displaced and partially replaced mitochondria and myofibrils..."

Enhancement of Muscle Mitochondrial Function by Growth Hormone
"...The 4-fold increase in plasma GH caused elevations in plasma IGF-I, insulin, glucose, and free fatty acids and a shift in fuel selection, with less carbohydrate (−69%) and leucine (−43%) oxidation and 29% more fat oxidation..."  NOTE: Leucine is an amino acid that has circulated some PSSM informational sites/forums as being vital to muscles - it's interesting that the findings in this study saw a decrease in Leucine usage...

"However, clinical testing with subjects (both genders) ingesting at least 5 grams of BCAA shortly prior to high-intensity resistance training are reasonably straightforward: BCAA substantially decrease muscle soreness, enhance recovery from exercise and consequently improve long-term performance. See:

Chronic Protein Deficiency In Horses
"Proteins basically provide the structure that makes us and every living animal we know into their unique shapes through the connective tissue of bones, ligaments, tendons, and muscle. They also make up a lot of other things in our bodies including defense mechanisms, sensors, and hair. I know this is basic, but I really want to get a few points across about protein in our horses..."


More stuff of interest:

Amino acid polarity:

Amino acid metabolism, biosynthesis, and catabolism:

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