LUTEINIZING HORMONE RECEPTOR IS PRESENT IN HUMAN ALDOSTERONE PRODUCING ADENOMAS AND MAY HAVE A ROLE IN THE REGULATION OF THE STEROID PRODUCTION

LUTEINIZING HORMONE RECEPTOR IS PRESENT IN HUMAN ALDOSTERONE PRODUCING ADENOMAS AND MAY HAVE A ROLE IN THE REGULATION OF THE STEROID PRODUCTION. S. Balzan*, F. Forini*, G. Nicolini*, L. Sabatino*, P. Iacconi†, A. Iervasi*, S. Turchi*, P. Di Cecco*, E. Fommei*‡. Fondazione G. Monasterio CNR-Regione Toscana*; Dept. of Internal Medicine‡, Dept. of Surgery†, Pisa University; Pisa, Italy. Objective. Luteinizing hormone (LH) receptor (LHR) is a G protein-coupled receptor which plays a critical role in the regulation of steroid hormones in gonadal tissues. The relationships of aldosterone with gonadal steroids have long being studied in normal and hypertensive subjects and LHR has been sporadically reported in Conn adenomas (primary aldosteronism). However, LHR role in the regulation of aldosterone production is still unclear. Aim of this study was to confirm the presence of LHR in aldosterone producing adenomas and to assess in vitro (adrenal cells in culture) the effects of LH on aldosterone production. Design. We investigated hypertensive patients who underwent laparoscopic adrenalectomy for Conn disease. During surgery fragments from adenomas were excised to obtain tissue homogenates and cell cultures for assessing LHR presence and steroid responsiveness to LH stimulation. Method. Tissue fragments from adenomas of five consecutive hypertensive patients (2F, 3M) were obtained and analyzed by real time PCR and western blot for LHR presence and expression. Cell cultures were also obtained and incubated for 24 hours. After assessing for cells viability, LH stimulation (300 ng/ml culture medium) was performed in 3 cases and aldosterone production in the culture medium evaluated after 6 hours; immunofluorescence of cultured cells with anti-LHR antibody was also performed. Results. 1. LHR mRNA and protein were detected in 4/5 patients and confirmed in cell cultures by immunofluorescence in 3/3. 2. In 2/3 patients, cells treated with LH increased their aldosterone production two-to-five folds after 6 hrs of stimulation compared to control conditions. Conclusions. These preliminary data confirm LHR presence and expression in aldosterone producing adenomas of hypertensive patients and suggest a role of LH in the regulation of the steroid production. These observations are to be confirmed in larger series of experiments and compared with results in normal adrenals.