Effect of Melatonin on Adrenal Steroid Secretion in Human Adrenocortical Carcinoma Cells

Presentation Number: MON 395
Date of Presentation: April 3rd, 2017

Kellie Fecteau*, Luca Giori and Hugo Eiler
University of Tennessee, Knoxville, TN

Abstract

Medical treatment for Cushing’s syndrome is recommended when either surgery is not an option or has been unsuccessful, or for those awaiting surgery (1). Enzyme inhibitors of steroidogenesis, such as metyrapone and mitotane, are central to medical treatment of Cushing’s however, as with most medical treatments, there may be adverse side effects (2). Melatonin, an over the counter hormone commonly used to treat jet lag and sleep disturbances, has been reported to inhibit ACTH-stimulated cortisol production in primate adrenal glands (3), and has an anti-gonadotropic effect in various species (4) however its effect on adrenocortical steroids in human is scarce.

To investigate the effect of melatonin on adrenal steroid production, human adrenocortical carcinoma cells (NCI-H295R) were counted, plated in 100 mm tissue culture plates, and divided into the following groups: (1) Control; media only, (2) 100 µM cyclic adenosine monophosphate (cAMP), (3) 100 µM melatonin, (4) 100 µM cAMP plus 1 µM melatonin, (5) 100 µM cAMP plus 10 µM melatonin, (6) 100 µM cAMP plus 100 µM melatonin for 24 and 48 hours. Analysis of cell culture media (n=18 per group) was performed using radioimmunoassay methodology. Concentrations of cortisol, progesterone, 17-hydroxyprogesterone, androstenedione, testosterone, and estradiol were determined. Groups 3 and 6 decreased androstenedione, testosterone, and estradiol concentrations at 24 and 48 hours compared to group 2 (P ≤ 0.05). Groups 3 and 6 decreased cortisol concentration at 24 hours compared to group 2 (P ≤ 0.05). Groups 3 through 6 failed to decrease progesterone and 17-hydroxyprogesterone concentrations and caused an increase in these hormones compared to groups 1 and 2 (P ≤ 0.05). Western blot analysis on cell pellets harvested from the different treatment groups revealed cAMP increased the content of steroidogenic enzymes 21-hydroxylase and aromatase compared to group 1. Group 3 decreased enzyme content by 50% at 48 hours while groups 4 through 6 did not decrease content of enzymes. Results of this study indicate that melatonin is effective in lowering several adrenal steroids in vitro and may yield similar effects on adrenal steroid concentrations in humans with Cushing’s syndrome.

 

Nothing to Disclose: KF, LG, HE