4-Bromodiphenyl Ether Causes Adrenal Gland Dysfunction in Rats during Puberty

Area of Science:

• Environmental Toxicology
• Endocrinology
• Developmental Biology

Background:

• Polybrominated diphenyl ethers (PBDEs) are widely used flame retardants known as endocrine disruptors.
• PBDEs can degrade into 4-bromodiphenyl ether (BDE3), a metabolite whose effects on adrenal function during development are unknown.

Purpose of the Study:

• To investigate the impact of BDE3 exposure on adrenal cortical cell function in male Sprague-Dawley rats during postnatal development.

Main Methods:

• Male Sprague-Dawley rats (35 days old) were administered BDE3 (0, 50, 100, 200 mg/kg/day) for 21 days.
• Serum hormone levels (aldosterone, corticosterone, ACTH) and adrenal gene expression (Cyp11b1, Scarb1, Star, Cyp11b2, Cyp21, Nr5a1) were analyzed.
• Cellular signaling pathways involving AMP-activated protein kinase (AMPK) and cyclic AMP-responsive element-binding protein (CREB) were assessed.

Main Results:

• BDE3 significantly increased serum aldosterone and corticosterone levels at 200 mg/kg, without affecting ACTH.
• Upregulation of key steroidogenic genes (Cyp11b1, Scarb1, Star, Cyp11b2, Cyp21, Nr5a1) was observed at 200 mg/kg.
• BDE3 decreased AMPK phosphorylation while increasing PGC-1α and CREB phosphorylation.

Conclusions:

• BDE3 exposure stimulates adrenal cortical cell function in developing male rats.
• The mechanism involves reduced AMPK phosphorylation and enhanced CREB activation.
• BDE3 represents a potential endocrine disruptor affecting adrenal steroidogenesis.