The expression of the POMC gene in the adrenal gland and adrenocortical tumors causing hypercortisolism in dogs

Abstract

Introduction: Hypercortisolism the most common endocrine disease in dogs. Chronic elevated plasma levels of cortisol result in clinical signs such as polyuria and polydipsia, polyphagia and alopecia. One of the causes for cortisol expression is an adrenocortical tumor (AT). So far, it was believed that AT secrete cortisol independently from the pituitary and ACTH. However, human research has shown that there is expression of adrenocorticotropic hormone (ACTH) and its precursor POMC in the tumors. In this research, the expression of POMC in ATs in dogs was studied in 26 carcinomas and 12 adenomas. For comparison also 15 normal adrenal cortexes served as control. Materials and methods: RT-PCR was performed on all the adrenal tissue samples. PCR products have been sequenced. After this, a qPCR was performed. Finally immunohistochemistry was done. Results: In the PCR, POMC expression was found in different samples, in both ATs and normal adrenal tissue. qPCR gave no reliable results. Results of the immunohistochemistry seemed to match with the results of the PCR, except for the normal tissue slides.