Volume 6, Spring 2008 - Saddleback College

Fall 2007 Biology 3A Abstracts
Department of Biological Science
Saddleback College
Mission Viejo, CA 92692
Creatine is a natural occurring amino acid that is found in muscle and nervous
tissue in all vertebrates. Along with its associated enzyme, creatine kinase, creatine and
phosphocreatine create a new energy transport chain that is twelve times faster than
oxidative phosphorylation. In this experiment the run time until exhaustion was measured
of the Western Fence lizard (Sceloporus occidentalis) prior to consumption of creatine and
after the consumption creatine. Runs were done using a table treadmill kept at a constant
speed until the lizards reached exhaustion. The results showed that the hypothesis was
confirmed and that there was a significant difference between the two groups. This shows
that creatine plays a role in the formation of energy in the lizards and allowed them to
utilize it more readily.
Introduction
Creatine and phosphocreatine are present in
all vertebrates along with the enzyme creatine kinase.
Creatine can keep the ATP to ADP ratio high while
acting as a buffer with the reaction [ATP + Creatine ↔
Phosphocreatine + ADP] through the creatine kinase
enzyme (Lee Fillers and Lyengar, 1988). Creatine
kinase also plays a key role in energy metabolism in
cells catalyzing the reversible transfer of phosphoryl
group from phosphocreatine to MgADP to form
creatine and MgATP (Woods and Guan, 1988)
(Andres, Ducray, Schlattner, and Wallimann 2008).
High energy phosphate buffers in the form of
phosphocreatine are also known as phosphagens
(Bessman and Geiger, 1981). In the form of
phosphocreatine, a common phosphagen, creatine, can
act as an intracellular energy pathway to help deliver
ATP. Further studies performed by, Rae, Digney,
McEwan, and Bates (2003), have showed that creatine
supplementation has a significant positive effect on
working memory and processing speed, this effect was
found along with ATP which can be re-synthesized
from phosphocreatine 12 times faster than via oxidative
phosphorylation. This is because ATP synthesis is
more complex than a direct phosphoryl transfer
reaction catalyzed by the enzyme creatine kinase
(Powers and Riordan, 1975). Phosphocreatine is an
important source of chemical energy in the heart, brain,
skeletal muscle, and macrophages; although no muscle
cells or macrophages can synthesize creatine. Cells
must take in creatine via the plasma by means of up hill
reaction (Loike, Azalutsky, Kaback, Miranda and
Silverstein, 1988). Creatine kinase has been identified
as a key enzyme in the homeostasis of maintaining
energy in vertebrates (Feng, Xu and Yan 2008).
Creatine is available in almost every nutrition
center and has many different forms in which can be
found as. Creatine is commonly taken by weight lifters
to have more energy in their muscles during exercise.
Some studies have shown that creatine loading during
exercise generates muscle mass (Gallo, MacLean and
Tyreman, 2008). Other cases added that creatine can
generate more energy in a system (Young, Bertram,
Theil, Petersen, Poulsen, Rasmussen, Malmendal,
Neilsen and Vestergaard 2007). For this experiment we
will use creatine monohydrate as our source of
creatine. By over loading Western Fence lizards with
creatine monohydrate the reaction involving
phosphocreatine will shift and enable the use of the
creatine pathway to help synthesize and re-synthesize
ATP from phosphocreatine. We hypothesize that if we
give creatine monohydrate to Western Fence lizards
(Sceloporus occidentalis) they will then be able to run
for a much longer period of time demonstrating greater
endurance.
Materials and Methods
Western Fence lizards (S. occidentalis) were
collected from Serrano Creek Park in Lake Forest,
California. The lizards (N=10) were housed in a glass
aquarium, which contained sand suitable for their
environment. Temperature was kept well regulated
between 75º and 85º Fahrenheit with a heat lamp and
Ultra Violet Lamp lighting the aquarium from above.
For an entire period of one month, the lizards were fed
three times a week and water was provided
accordingly.
Prior to obtaining the lizards, 500 pinhead
crickets were purchased from Pet Smart in Rancho
Santa Margarita, Ca, and 600 grams of Creatine
Monohydrate pure powder was purchased from the
Now Sport Nutrition website. Furthermore, for the first
two consecutive weeks of the experiment the lizards
were fed 40 pinhead crickets three times a week.
Before running the lizards, to obtain the control run
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Saddleback Journal of Biology
Spring 2008