Muscular Hypertrophy

This bison bull is already well-muscled. Just imagine what he might look like with double the muscle mass. Such a thing is possible.

---

When I read my first novel about Jack Reacher, a larger-than-life character created by British author, Lee Child, I was struck by several things. First, he was huge, at 6’5” and 250 pounds. He seemed anti-social, appearing to perhaps be on the “spectrum” of autism, he seemed to live on coffee, hamburgers and pie, and he was really strong. That is the part that confused me. Child described him as having rippling body-builder type muscles, yet he never ever worked out. He was that way naturally. Well, that didn’t sound natural to me as I considered my mostly failed attempts at increasing my own body strength.

While researching last week’s column on muscle though, I ran across a possible explanation for Reacher’s size and body condition. I don’t know if author Lee Child knew about this or not, but it really seems to fit. It is a condition known to the medical world as myostatin-related muscle hypertrophy, hypertrophy meaning “the increase in the volume of an organ or tissue due to the enlargement of its component cells (Wikipedia).” While hypertrophy refers only to muscle fiber size, myostatin also controls the number of muscle fibers, which may increase with decreased myostatin. In addition, the condition is characterized by a decrease in body fat and an increase in muscle strength, making for a body-builder physique and Herculean strength with little or no effort.

Myostatin-related muscle hypertrophy is a rare condition, but has been known for over 200 years. It was first described in 1807, then found to occur in several breeds of cattle including Piedmontese (first discovered in Italy, 1897) and the Parthenais (first discovered in France, 1893) as well as the Belgian Blue and Limousin cattle. Here it is called double-muscle and in the more extreme cases, the animals are beyond huge to the point where all the extra muscle is an impediment to locomotion.

Myostatin is a protein produced by the MSTN gene and found only in skeletal, not smooth or cardiac, muscle. Its purpose is to limit muscle growth, to make sure that muscles don’t grow so large as to become a liability to the animal. For instance, imagine a double-muscled prey animal of almost any kind. To be sure, it is strong and dangerous, but it would also be so slow and ponderous that it would be an easy target. Lean and agile is the preferred strategy for avoiding predation.

When myostatin is suppressed or ineffective, double-muscling (mostly increasing size, but adding extra muscle fibers does occur) or hypertrophy occurs. There are at least nine ways for this to happen. The most extreme is when both parents contribute a variant or mutated MSTN gene that does not produce myostatin at all. The muscles of offspring that have virtually no myostatin can grow to enormous size, so large that movement is difficult. Heterozygous individuals, humans included, have one mutant gene and one regular gene. These individuals may just have better muscle definition and significantly more strength than normal.

One of the interesting things about myostatin deficiency is that it doesn’t seem to otherwise challenge the individual with other health issues. All other bodily functions work well and it does not influence intelligence.

Shortly after the discovery of myostatin in 1997, researchers were convinced that they had found the key to reversing, or at least stalling, the impacts of devastating muscle-wasting diseases such as muscular dystrophy. They theorized that if the myostatin gene could be turned off, then the resulting increased growth of muscle could counteract the losses. To date, though, these trials have not shown much promise.

On the animal side, double-muscled livestock have shown potential for increased commercial meat production. The meat is typically leaner and even more tender than normal. Research continues to determine if double-muscling might help with protein shortages across the globe. This may require the deletion of a single gene rather than recombination of genes or mixing of genes from different species and may be more acceptable to regulators.

One of the most interesting things about the myostatin pathway is that it regulates muscle mass in virtually all species of vertebrates, from fish to humans, tested to this point. This is a very common and obviously very important gene and demonstrates that we have more in common that we might have thought.

---

Help Idaho Wildlife

When we traveled across the state in October 2017, most of the vehicles we saw using the wildlife management areas did not have wildlife plates. Buying wildlife plates is a great way for non-hunters and hunters alike to support wildlife-based recreation like birding.

C'mon folks, let's help Idaho's wildlife by proudly buying and displaying a wildlife license plate on each of our vehicles! 

See below for information on Idaho plates. Most states have wildlife plates so if you live outside Idaho, check with your state's wildlife department or vehicle licensing division for availability of state wildlife plates where you live. 

And tell them that you heard about it from Nature-track.com!

Wildlife License Plates

Great news! as of 2024, there are three NEW designs for license plates. They still are bluebird, cutthroat trout and elk, but they are beautiful.

Idaho Wildlife license plates provide essential funding that benefits the great diversity of native plants and wildlife that are not hunted, fished or trapped—over 10,000 species or 98% of Idaho’s species diversity. Game species that share the same habitats (such as elk, deer, antelope, sage-grouse, salmon, trout) also benefit from these specialty plates.

No state tax dollars are provided for wildlife diversity, conservation education and recreation programs. Neither are any revenues from the sale of hunting or fishing licenses spent on nongame species. Instead, these species depend on direct donations, federal grants, fundraising initiatives—and the Idaho Wildlife license plates.

Both my vehicles have Bluebird Plates. I prefer the bluebird because the nongame program gets 70 percent of the money from bluebird plates, but only 60 percent of the money from elk and trout plates - 10 percent of the money from elk plates supports wildlife disease monitoring and testing programs (to benefit the livestock industry) and 10 percent from cutthroat plates supports non-motorized boat access.

Incidentally, in 2014, the Idaho Legislature denied the Department of Fish and Game the ability to add new plates or even to change the name of the elk and cutthroat plates (very specific) to wildlife and fish plates, a move that would have allowed for changing images occasionally and generating more revenue. It would seem that they believe that we Idahoans don't want a well funded wildlife program.

I think it is time we let the Legislature know that Idahoan support wildlife funding and that we would like to see these generic plates come to fruition.