Exposure of dog thyroid slices to acetylcholine induces refractoriness to its subsequent stimulation of glucose oxidation

• Published in: Archives of biochemistry and biophysics Vol. 225; no. 1; pp. 66 - 74
• Main Authors: Arem, Ridha, Chayoth, Reuben, Shenkenberg, Todd D., Miller, Samuel I., Chou, Margaret C.Y., Field, James B.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.08.1983
• Subjects: Acetylcholine - pharmacology; Animals; Cyclic AMP - metabolism; Dogs; Glucose Oxidase - metabolism; In Vitro Techniques; Thyroid Gland - drug effects; Thyroid Gland - enzymology; Time Factors
• ISSN: 0003-9861; 1096-0384
• DOI: 10.1016/0003-9861(83)90007-3

An initial incubation of dog thyroid slices with 0.1 or 1 μ m acetylcholine (ACH) for at least 2 h decreases its subsequent stimulation of [1- 14C]glucose oxidation. Refractoriness persists for as long as 6 h in the absence of ACH. While new protein synthesis is essential for recovery, it is not necessary for its induction. Refractoriness is prevented when 25 μ m tropicamide, an atropine-like drug, is present from the beginning of the initial incubation, but not when it is added after 2 h of incubation of slices with ACH, indicating that at this time ACH is no longer necessary for refractoriness. During refractoriness induced by ACH, stimulation of glucose oxidation by thyroid-stimulating hormone, prostaglandin E 1, dibutyryl cyclic AMP, and cholera toxin, but not menadiol, is also significantly diminished. Incubation of thyroid slices with ACH does not modify its stimulation of iodide organification or 32P i incorporation into phospholipids. These results suggest that the desensitization is not due to changes in the ACH receptor but rather to intracellular metabolic effects. This phenomenon may be important in the regulation of cholinergic effects on the thyroid.