Adult-onset hypogonadotropic hypogonadism caused by aberrant expression of aromatase in an adrenocortical adenocarcinoma.

Estrogen-secreting adrenal cancers are extremely rare, with feminizing symptoms attributed to aromatase expression in the adrenal tumor. We describe a case of hypogonadotropic hypogonadism as a consequence of aberrant aromatase expression in a patient with adrenocortical adenocarcinoma. A 54 year-old man presented with a two month history of gynecomastia and reduced libido. Endocrine biochemistry at presentation showed hypogonadotropic hypogonadism (LH 2.4 U/L, FSH <1.0 IU/L, testosterone 2.8 nmol/L) with increased serum estrone (E(1), 821 pmol/L) and estradiol (E(2), 797 pmol/L) and subclinical ACTH-independent hypercortisolism (serum cortisol post 1mg overnight dexamethasone suppression test, 291 nmol/L). A right adrenal mass was identified on CT scanning and the patient underwent an open adrenalectomy. Post-operative evaluation showed normalization of serum levels of E(1) (95 pmol/L), E(2 )(109 pmol/L), testosterone (11.4 nmol/L), LH (4.1 U/L) and FSH (5.9 IU/L), and of cortisol dynamics. Immunohistochemistry of the adrenal cancer confirmed aberrant expression of aromatase in most, although not all, carcinoma cells. Transcripts associated with utilization of promoters II, I.1 and I.3 were prominently represented in the tumor aromatase mRNA. This case highlights that clinical features of feminizing adrenocortical carcinomas can be secondary to estrogen production by aberrantly transcribed and translated aromatase within the tumor. Even in males, gonadotropin secretion is subject to predominantly estrogen-mediated feedback-inhibition. The diagnosis of adrenocortical adenocarcinoma should be considered in men presenting with low testosterone and gonadotropins, particularly in the presence of feminizing features.

Estrogen biosynthesis in human H295 adrenocortical carcinoma cells.

Adrenocortical carcinoma is an uncommon malignancy and feminizing symptoms secondary to adrenal estrogen-secretion are extremely rare. The direct secretion of estradiol by adrenocortical tumors requires, in addition to the expression of aromatase (CYP19), the expression of one or more of the reductive 17beta-hydroxysteroid dehydrogenases. The expression of CYP19 transcripts and protein were markedly induced in the H295 adrenocortical carcinoma cell line after treatment with either forskolin or vasoactive intestinal peptide (VIP). Western immunoblotting demonstrated a marked induction of the CYP19 protein of characteristic size after only a short (6h) treatment period with VIP or forskolin. The CYP19 mRNA transcripts were derived from both promoters PII (Ic) and I.3 (Id) after treatment with both agents. The reductive type 5 17beta-hydroxysteroid dehydrogenase (AKR1C3) was also constitutively expressed in the H295 cells but neither its mRNA transcript nor protein levels were altered after forskolin or VIP treatment. Western immunoblotting of an estrogen-secreting adrenal carcinoma revealed notable levels of both aromatase and AKR1C3 expression while an aldosterone-producing adrenal adenoma lacked aromatase expression and showed a reduced level of AKR1C3 expression. Immunohistochemistry of the carcinoma-bearing adrenal revealed localization of AKR1C3 not only in the tumor but also principally in the zona reticularis of the normal adrenal tissue. Adrenal aromatase and AKR1C3 expression therefore appear to be features of adrenocortical malignancies that are associated with biosynthesis of active estrogen.

GnRH-mediated DAN production regulates the transcription of the GnRH receptor in gonadotrope cells.

The primary function of gonadotropin-releasing hormone (GnRH) is the regulation of pituitary gonadotropin hormone gene transcription, biosynthesis and release. These effects are mediated through intracellular mobilization of Ca2+ and activation of PKC isoforms and MAP kinases. We show here that DAN (differential screening-selected gene aberrative in neuroblastoma) which is a secreted bone morphogenic protein (BMP) antagonist belonging to the TGFbeta protein superfamily, is controlled by GnRH in murine gonadotrope cells. Acute GnRH stimulation induced a rapid, 27-fold, elevation of DAN mRNA, accompanied by an approximate 3-fold increase in the amount of mature DAN glycoprotein in the cell cytoplasm and in DAN secretion into the culture medium. Incubation of L beta T2 cells in DAN-containing medium altered the levels of a number of cellular proteins. Two of these were identified as the steroidogenic acute regulatory protein (StAR) and the actin-related protein 2/3 complex subunits 2 (p34-ARC) which are primarily involved in steroidogenesis and cytoskeleton remodelling, respectively. DAN caused an approximate 2-fold specific elevation in the cytoplasmic levels of both these proteins in L beta T2 cells. We further tested the effects of DAN on classical GnRH effects viz. gonadotropin and GnRH receptor gene expression. Co-transfection of L beta T2 cells with DAN and gonadotropin subunit promoter luciferase reporter genes had no effect on GnRH stimulation of alpha GSU and LH beta or on the additive GnRH and activin induction of FSH beta subunit transcription. However, co-transfection of DAN markedly inhibited the synergistic activation of GnRH and activin on GnRH receptor gene expression thus implicating DAN as a novel autocrine/paracrine factor that modulates GnRH function in pituitary gonadotropes.