Effect of hypothyroidism on glucose transport and metabolism in rat small intestine

• Published in: Biochimica et biophysica acta Vol. 1179; no. 1; pp. 76 - 80
• Main Authors: Khoja, Samir M., Kellett, George L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 07.10.1993; Elsevier Science
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Biological Transport; Body Weight; Carbohydrates; Fundamental and applied biological sciences. Psychology; Glucose - metabolism; Glucose transport; Hexokinase - metabolism; Hypothyroidism; Hypothyroidism - blood; Hypothyroidism - metabolism; Intestinal Mucosa - metabolism; Jejunum - metabolism; Male; Organ Size; Oses; Other biological molecules; Phosphofructokinase-1 - metabolism; Pyruvate Kinase - metabolism; Rat small intestine; Rats; Rats, Wistar; FT 3; FT 4; TT 4; TT 3; Glucose transport; Hypothyroidism; Rat small intestine; Endocrinopathy; Vertebrata; Mammalia; Rat; Biological transport; Rodentia; Thyroid diseases; Glucose; Metabolism; Small intestine
• ISSN: 0167-4889; 0006-3002; 1879-2596
• DOI: 10.1016/0167-4889(93)90073-X

The effect of experimental hypothyroidism on the absorption, transmural transport and metabolism of glucose was studied by perfusion of isolated loops of rat jejunum in vitro. When expressed on a dry weight basis, the rate of absorption was enhanced by 32% ( P < 0.01); when expressed on a length basis there was no significant change, since the enhancement per unit weight was almost exactly compensated by a diminution in mass per unit length in the hypothyroid state. When expressed in either units, there was a significant enhancement in transmural transport (+123% and +77%, respectively, both P < 0.001), which reflected in part a diminution in the rate of glucose utilization (−29%, P < 0.01 and −43%, P < 0.001, respectively). The changes in glucose utilization were matched by changes in lactate production. Three factors contributed to the diminution in glucose utilization in the hypothyroid state: a diminution in the concentration of 6-phosphofructo-1-kinase (−35%, P < 0.05), and increase in the S 0.5 of 6-phosphofructo-1-kinase for fructose 6-phosphate from 0.4 to 0.6 mM and a fall in the mucosal concentration of fructose 2,6-bisphosphate (−56%, P < 0.05). From the point of view of the whole animal, there is little if any change in the capacity of the intestine to absorb glucose from the lumen, but there is a large enhancement of transmural transport that is metabolically driven.