Regulation of aldosterone secretion by several aberrant receptors including for glucose-dependent insulinotropic peptide in a patient with an aldosteronoma.
BACKGROUND
Primary adrenal Cushing's syndrome can result from the aberrant adrenal expression of several hormone receptors; this mechanism has not been explored in detail in aldosterone-producing tumors.


OBJECTIVE
The objective of the study was to evaluate a 56-yr-old male patient with an aldosteronoma for the regulation of aldosterone secretion by aberrant hormone receptors.


RESULTS
Renin-independent stimulation of aldosterone secretion was observed in vivo after a mixed meal, oral glucose, or administration of glucose-dependent insulinotropic peptide (GIP), vasopressin, and tegaserod. The mixed meal-mediated stimulation of aldosterone was not present in five other cases of aldosteronoma. A smaller response of aldosterone after GIP infusion was observed in a normal subject. Aldosterone secretion was stimulated by GIP in primary cultures of this patient's aldosteronoma. Increased expression of GIP receptor was found in this aldosteronoma by real-time RT-PCR and immunohistochemistry. The GIP receptor protein was also found at lower levels in zona glomerulosa cells of the normal adjacent adrenal gland. Increased expression of serotonin 4 and ACTH receptors was also present in this aldosteronoma.


CONCLUSIONS
This case report provides new evidence of the implication of aberrant hormone receptors in the regulation of this aldosteronoma and suggests that further detailed studies of the role of aberrant hormone receptors in this frequent pathology should be undertaken.
Lampron
Antoine
A
Division of Endocrinology, Centre Hospitalier de l'Université de Montré al, Montré al, Qué bec, Canada H2W 1T8.
Bourdeau
Isabelle
I
Oble
Sylvie
S
Godbout
Ariane
A
Schürch
Walter
W
Arjane
Philippe
P
Hamet
Pavel
P
Lacroix
André
A
D000306:Adrenal Cortex Neoplasms / Q000378:metabolism*; D018246:Adrenocortical Adenoma / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000450:Aldosterone / Q000378:metabolism*; D005749:Gastric Inhibitory Polypeptide / Q000494:pharmacology; D006801:Humans; D008297:Male; D008875:Middle Aged; D018043:Receptors, Corticotropin / Q000502:physiology; D011964:Receptors, Gastrointestinal Hormone / Q000032:analysis / Q000502:physiology*; D044422:Receptors, Serotonin, 5-HT4 / Q000502:physiology; D017483:Receptors, Vasopressin / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction
D018043:Receptors, Corticotropin; D011964:Receptors, Gastrointestinal Hormone; D017483:Receptors, Vasopressin; D044422:Receptors, Serotonin, 5-HT4; D000450:Aldosterone; D005749:Gastric Inhibitory Polypeptide; D000324:Adrenocorticotropic Hormone; C041086:gastric inhibitory polypeptide receptor