Telfairia occidentalis stimulates hepatic glycolysis and pyruvate production via insulin-dependent and insulin-independent mechanisms

Toyin Mohammed Salman; Mayowa Adewale Iyanda; Abdul-Musawwir Alli-Oluwafuyi; Sheu Oluwadare Sulaiman; Abdullateef Isiaka Alagbonsi

doi:10.1016/j.metop.2021.100092

Telfairia occidentalis stimulates hepatic glycolysis and pyruvate production via insulin-dependent and insulin-independent mechanisms

Metabol Open. 2021 Apr 14:10:100092. doi: 10.1016/j.metop.2021.100092. eCollection 2021 Jun.

Authors

Toyin Mohammed Salman¹, Mayowa Adewale Iyanda¹, Abdul-Musawwir Alli-Oluwafuyi², Sheu Oluwadare Sulaiman^{3

4}, Abdullateef Isiaka Alagbonsi⁵

Affiliations

¹ Department of Physiology, College of Health Sciences, University of Ilorin, Ilorin, Nigeria.
² Department of Pharmacology and Therapeutics, College of Health Sciences, University of Ilorin, Ilorin, Nigeria.
³ Physiology Department, Kampala International University - Western Campus, Ishaka-Bushenyi, Uganda.
⁴ Department of Morphology (Cell Biology), Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
⁵ Department of Clinical Biology (Physiology), School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Huye Campus, Rwanda.

Abstract

Background: Telfairia occidentalis (TO), a plant consumed for its nutritional and medicinal values, exhibits hypoglycaemic effect. However, the metabolic fate of the glucose following TO-induced insulin secretion and consequent hypoglycaemia is not clear.

Objective: This study determined the effect of ethyl acetate and n-hexane fractions of TO leaf extracts on some biochemical parameters in the glucose metabolic pathway to explain the possible fate of blood glucose following TO-induced hypoglycaemia.

Methods: Eighteen male Wistar rats (180-200 g) divided into control, n-hexane TO fraction- and ethyl acetate TO fraction-treated groups (n = 6/group) were used. The control animals received normal saline while the treated groups received TO at 100 mg/kg for seven days. After 24 h following the last dose, the animals were anaesthetised using ketamine; blood samples were collected and livers harvested to determine some biochemical parameters.

Results: Ethyl acetate TO fraction significantly increased plasma insulin, liver glucokinase activity and plasma pyruvate concentration, but significantly decreased plasma glucose and liver glycogen, without significant changes in plasma lactate, glucose-6-phosphate, liver glucose-6-phosphatase and lactate dehydrogenase activities when compared with control. N-hexane TO fraction significantly reduced liver glucose-6-phosphatase activity and glycogen but significantly increased plasma pyruvate, without significant changes in plasma glucose, insulin, glucose-6-phosphate and lactate concentrations; and liver glucokinase and lactate dehydrogenase activities.

Conclusion: The present study showed that insulin-mediated TO-induced hypoglycaemia resulted in the stimulation of glycolysis and pyruvate production via insulin-dependent and insulin-independent mechanisms.

Keywords: ANOVA, Analysis of Variance; ATP, Adenosine triphosphate; EATO, Ethyl acetate TO fraction; ELISA, Enzyme-linked immunosorbent assay; G6P, Glucose-6-phosphate; G6PD, Glucose-6-phosphate dehydrogenase; G6Pase, Glucose-6-phosphatase; GCK, Glucokinase; GLUT, Glucose transporter; GSIS, glucose-stimulated insulin secretion; Glucoregulatory enzymes; Glucose metabolites; Glycogen; HClO4, Perchloric acid; HRP, Horseradish Peroxidase; IMGU, Insulin-mediated glucose uptake; Insulin; KOH, Potassium hydroxide; LDH, Lactate dehydrogenase; MCT, Monocarboxylate transporters; NAD, Nicotinamide adenine dinucleotide; NHTO, N-hexane TO fraction; Plasma glucose; SEM, Standard error of mean; TCA, Tricarboxylic acid cycle; TO, Telfairia occidentalis; Telfairia occidentalis.