Case study on obesity: A 19-year-old female college student sought medical help because she was 30 kg overweight. Most of her excess weight was in the form of adipose tissue. A medical history revealed that her diet was extremely poor. She consumed virtually no vegetables, whole grains or legumes. Much of her caloric intake was comprised of simple carbohydrates - crackers, white rice, white bread, pastries, desserts, soft drinks, and beer. However, her dietary fat intake was actually quite moderate.

 

1. What clinical test could would indicate whether this patient could mobilize the triglyceride that is stored in her adipose tissue?
2.  What kind of unsaturated fatty acid can be synthesized from glucose? What metabolic reactions would be involved in this process?

Q1. The clinical tests that can indicate whether the patient can mobilize triglycerides stored in adipose tissue are:

-Glycerol levels

-Insulin levels

-Lipidic profile

Glycerol is found as part of vegetable and animal oils and fats such as mono, di or triacylglycerides (glycerol and one, two or three molecules of saturated or unsaturated fatty acids, respectively) and also of phospholipids, specifically phosphoglycerides or phosphoacylglycerols (glycerol, fatty acids and phosphate group) that are members of the cell membrane of animals and plants.

When the human body uses these fats, stored in the liver and adipose tissue, as a source of energy, lipases hydrolyze triglycerides, releasing glycerol and fatty acids into the bloodstream. Glycerol is taken up by the liver, converted into glyceraldehyde-3-phosphate and, depending on the body's needs (Figure 2), used to provide energy for cell metabolism (glycolysis) or to be transformed into glucose (gluconeogenesis).

Insulin is a hormone released from the pancreas and its main function is to help cells take up sugar (glucose). Insulin also stimulates the synthesis and storage of triglycerides and proteins.

Q2.

The synthesis of unsaturated fatty acids depends on the generating reaction of the synthesis of saturated fatty acids. In addition to the essential fatty acids, linoleic and α-linoleic, the production of fatty acids from simple precursors is possible.

The GLUT4 transporter enters glucose by crossing the cell membrane and phosphorylation by hexokinase occurs.

Glucose is transformed into glucose-6-phosphate by a process called glycolysis, which eventually results in pyruvate where it is oxidized to acetyl-CoA. Acetyl-CoA has in common that it brings together the catabolism of fats and carbohydrates. In the synthesis of fatty acids, acetyl-CoA is formed into Malonyl-CoA, catalyzed by acetyl-CoA carboxylase. This process is generated in the cytosol, we know that desaturases form unsaturated fatty acids. Humans lack Δ12 and Δ15 desaturases, therefore linoleic acid (18: 2 Δ9,12) and α-linolenic acid (18: 3 Δ9,12,15) are essential because they create double bonds at these positions . The reaction can be generated to obtain palmitoleic acid and oleic acid, monounsaturated fatty acids Δ9 through the desaturation of fatty acids, palmitate and stearate, this product is obtained by the reaction of mixed oxidases, which are those that cause the oxidation of 2 different substrates such as NADPH and fatty acid, the fatty acid, when oxidized, releases hydrogen and generates double bonds, and the oxygen that when joined with the hydrogen produces water