Altered expression of G proteins in thyroid gland adenomas obtained from hyperthyroid cats.
OBJECTIVE
To determine whether expression of G proteins (G(i) and G(s)) is altered in thyroid gland adenomas obtained from hyperthyroid cats.


METHODS
Adenomatous thyroid glands obtained from 8 hyperthyroid cats and thyroid glands obtained from 4 age-matched euthyroid cats.


METHODS
Expression of G(i) and G(s) was quantified in enriched membrane preparations of thyroid gland tissue, using immunoblotting with G(i) and G(s) antibodies and toxin-catalyzed ADP-ribosylation.


RESULTS
Expression of G(i) was significantly reduced in thyroid gland adenomas from hyperthyroid cats, compared with normal thyroid gland tissue from euthyroid cats. Expression of G(s) was similar between the 2 groups.


CONCLUSIONS
A decrease in expression of G in adenomatous thyroid glands of cats may reduce the negative inhibition of the cAMP cascade in thyroid cells, leading to autonomous growth and hypersecretion of thyroxine. Understanding the molecular mechanisms for hyperthyroidism in cats may lead to better treatment or, ultimately, prevention of the disease.
Hammer
K B
KB
Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104-6010, USA.
Holt
D E
DE
Ward
C R
CR
D020727:ADP-Ribosylation Factors / Q000737:chemistry; D000236:Adenoma / Q000378:metabolism / Q000503:physiopathology / Q000662:veterinary*; D000276:Adjuvants, Immunologic / Q000737:chemistry; D000818:Animals; D015153:Blotting, Western / Q000662:veterinary; D002371:Cat Diseases / Q000503:physiopathology*; D002415:Cats; D002772:Cholera Toxin / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D019204:GTP-Binding Proteins / Q000378:metabolism* / Q000502:physiology; D005786:Gene Expression Regulation; D006980:Hyperthyroidism / Q000209:etiology / Q000662:veterinary*; D008163:Luminescent Measurements; D037342:Pertussis Toxin; D018709:Statistics, Nonparametric; D013961:Thyroid Gland / Q000473:pathology; D013964:Thyroid Neoplasms / Q000378:metabolism / Q000503:physiopathology / Q000662:veterinary*; D010566:Virulence Factors, Bordetella / Q000737:chemistry
D000276:Adjuvants, Immunologic; D010566:Virulence Factors, Bordetella; D002772:Cholera Toxin; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D020727:ADP-Ribosylation Factors