Defective Glucose and Water Transport in Two Forms of Diabetes (Part 3 of 3)
Insulin: Discovery, Purification, and Mechanism
Insulin is accidentally discovered in 1889 by
Oscar Minkowski and Josef von Mering after a friendly disagreement about
whether the pancreas contains lipase. They surgically remove the pancreas of a
dog for the study which eventually observed to urinate more. However, they
failed to extract substance to reverse the effect of removing the pancreas
(Nelson).
Not until 1921 when Frederick Banting, Charles
Best, and JJR MacLeod took up the problem and found anti-diabetic factors in
the pancreas. They called it insulin from the Latin word “insula”, meaning
islands since insulin was extracted from the islets of Langerhans. The same
year, purification was successful (“Insulin | Definition, Structure, and
Function”).
In 1922, they tested the purified insulin on
Leonard Thompson and within a few days, they observed a drop of glucose and
ketone in the body (Nelson).
A Nobel Prize was awarded to Banting and
MacLeod in 1923 and since then insulin was isolated from the porcine pancreas.
In 1980, through genetic engineering techniques, the mass production of insulin
was developed (“Insulin | Definition, Structure, and Function”).
Insulin is composed of two chains of amino
acids derived from preproinsulin. Preproinsulin is an inactive substance of
Chain A, Chain B, C-peptide, and a signal peptide. When the preproinsulin
reached the Endoplasmic reticulum, the signal peptide will be cleaved off leaving
the still inactive proinsulin. As it procced to the Golgi apparatus, a
disulfide bond in the cysteine residue is formed and the C-peptide will
eventually cleave off producing the active insulin while the C-peptide will be
degraded and excreted. (Vasiljević, et al.).
 |
Figure 4. Synthesis of insulin from preproinsulin. |
Diabetes is often related to blood sugar with the early signs or
symptoms of excessive urination. However, there are two forms of diabetes –
diabetes mellitus and diabetes insipidus. The urine in diabetes mellitus is
sweet while in diabetes insipidus is very dilute or tasteless.
Both forms of diabetes are hormone-related. Insulin is secreted by the
pancreas for diabetes mellitus while vasopressin is secreted by the pituitary
glands for diabetes insipidus.
Diabetes prevalence in the Philippines is quite alarming. This only gives us the warning to keep our health monitored and choose a lifestyle that will keep us fit.
References:
Baclig, Cristina Eloisa. “Diabetes: A Bitter Health Crisis for Filipinos.” INQUIRER.Net, 21 July 2021, newsinfo.inquirer.net/1461980/diabetes-a-bitter-health-crisis-for-filipinos.
Bryant, Nia J., et al. “Regulated Transport of the Glucose Transporter GLUT4.” Nature Reviews Molecular Cell Biology, vol. 3, no. 4, 2002, pp. 267–77. Crossref, https://doi.org/10.1038/nrm782.
“Diabetes Insipidus and Diabetes Mellitus.” The Diabetic Voice.Com, www.the-diabetic-voice.com/diabetes-insipidus-and-diabetes-mellitus.html. Accessed 26 Apr. 2022.
Felman, Adam. “What’s to Know about Diabetes Insipidus?” Medical News Today, 7 Apr. 2022, www.medicalnewstoday.com/articles/183251.
“Glucose Regulation and Utilization in the Body.” Nutrition FN 225, media.lanecc.edu/users/powellt/FN225OER/Carbohydrates/FN225Carbohydrates5.html. Accessed 26 Apr. 2022.
“Insulin | Definition, Structure, and Function.” Encyclopedia Britannica, www.britanica.com/science/insulin.
Nelson, David. Lehninger Principles of Biochemistry. 7th ed., W.H. Freeman, 2017.
Qureshi, Sana, et al. “Diabetes Insipidus: Celebrating a Century of Vasopressin Therapy.” Endocrinology, vol. 155, no. 12, 2014, pp. 4605–21. Crossref, https://doi.org/10.1210/en.2014-1385.
Tahrani, Abd A., et al. “Management of Type 2 Diabetes: New and Future Developments in Treatment.” The Lancet, vol. 378, no. 9786, 2011, pp. 182–97. Crossref, https://doi.org/10.1016/s0140-6736(11)60207-9.
Vasiljević, Jovana, et al. “The Making of Insulin in Health and Disease.” Diabetologia, vol. 63, no. 10, 2020, pp. 1981–89. Crossref, https://doi.org/10.1007/s00125-020-05192-7.
“What Is Diabetes?” Centers for Disease Control and Prevention, 2 Mar. 2022, www.cdc.gov/diabetes/basics/d
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