Effects of Hypothyroidism on Serum Immunoreactive Insulin, Free Fatty Acids and Blood Sugar in the Dog as Tested for Oral Glucose Tolerance - Corrective Effects of Thyroxine Therapy

Abstract

The effect of T therapy (T 0.5 and T 10) on BS, serum IRI and FFA levels of thyroidectomized dogs during an OGTT was studied.Either T dose failed to res tore the BS profiles in these animals: T 10 corrected the delayed onset of hyperglycemia after glucose load but it definitely raised the BS baseline; T 0.5 also enhanced this baseline and, also, reduced the magnitude of hyperglycemia.Both T doses reduced the overnormal serum IRI levels observed in the thyroidectomized dogs both in the post-absorptive condition and during the test; T 10 was more effective than T 0.5; normal serum IRI levels, however, were not achieved during the test.T therapy only partially corrected the serum FF A profiles of the thyroidectomized dogs. Both T 0.5 and T 10 restored both serum FF A baseline and return to baseline at the end of the test, but they overshot to overnormal serum FFA values du ring the fall early after glucose load.

Associations between cardiovascular risk, insulin resistance, β-cell function and thyroid dysfunction: a cross-sectional study in She ethnic minority group of Fujian Province in China

“…In most other studies, the concentration of insulin in hypothyroidism is reported to be normal (28) or decreased (29,30), which is similar to our result. Insulin sensitivity in hypothyroid patients has been found to be normal (31) or decreased (32)(33)(34).…”

Prevalence of thyroid dysfunction in patients with Type 2 diabetes mellitus and its correlation with insulin resistance and serum markers for autoimmune thyroiditis

“…In most other studies, the concentration of insulin in hypothyroidism is reported to be normal 23 or decreased, 24,25 which is similar to our result. In hypothyroidism, glucose homeostasis is affected due to reduced intestinal glucose absorption, hepatic gluconeogenesis and glycogenolysis and peripheral tissue glucose disposal.…”

Effect of hypothyroidism on insulin sensitivity and glucose tolerance in dogs

“…61,62 The reason for the association is not entirely clear, but an increase in plasma free fatty acids and alterations in adipocytokines and inflammatory cytokines have been proposed as possible mediators. Although these factors were not evaluated in the present study, free fatty acids are reportedly unchanged or decreased in hypothyroid dogs 5,7 ; therefore, their role in hypothyroid-mediated insulin resistance is unclear.…”

“…[4][5][6][7] Low S I and impaired glucose use associated with hypothyroidism have been identified in other animal species as well. 8,9 Whether the glucose intolerance in hypothyroidism is the direct result of thyroid hormone deficiency or whether hormones with counter-regulatory effects on insulin mediate the development of insulin resistance is unclear.…”