Adrenal Gland: Structure, Function, and Mechanisms of Toxicity

Abstract

The adrenal gland is one of the most comm on endocrine organs affected by chemically induced lesions. In the adrenal cortex, lesions are more frequent in the zona fasciculata and reticularis than in the zona glomerulosa. The adrenal cortex produces steroid hormones with a 17-carbon nucleus following a series of hydroxyla tion reactions that occur in the m itochondria and endoplasm ic reticulum. Toxic agents for the adrenal cortex include short-chain aliphatic compound s, lipidosis inducers , amphiphilic compounds , natural and synthetic steroids, and chemicals that affect hydroxyla tion. Morphologic evaluation of cortical lesions provides insight into the sites of inhibition of steroidogenesis. The adrenal cortex response to injury is varied. Degeneratio n (vacuolar and granular), necrosis, and hem orrhage are common ndings of acute injury. In contrast, chronic reparative processes are typically atrophy, brosis, and nodular hyperplasia. Chem ically induced proliferative lesions are uncom m on in the adrena l cortex. The adrenal medulla contains chrom af n cells (that produce epinephrine, norepineph rine, chromogranin, and neuropeptides) and ganglion cells. Proliferative lesions of the medulla are common in the rat and include diffuse or nodular hyperplasia and benign and malignant pheochrom ocytoma. Mechanism s of chromaf n cell proliferation in rats include excess growth hormone or prolactin, stimulation of cholinergic nerves, and diet-induced hypercalcem ia. There often are species speci city and age dependenc e in the developme nt of chemically induced adrenal lesions that should be considered when interpreting toxicity data.

Prolactin induces adrenal hypertrophy

“…Its cells are polyhedral and have many intracytoplasmic lipid droplets (18). These lipids, mostly cholesterol and cholesterol esters, are used as substrates for steroidogenesis (19). These lipid droplets can be mobilized from these stores to mitochondria for the synthesis of Rats received 4 mg/kg domperidone, sc.…”

The stress of being contaminated? Adrenocortical function and reproduction in relation to persistent organic pollutants in female black legged kittiwakes

“…The adrenal gland is one of the most common target for chemically induced lesions (Rosol et al 2001). Because of several characteristics as: its large blood supply, its lipophilicity (allowing the accumulation of lipophilic compounds), its high concentration of cytochrome P450 that can also bioactivate toxicants, and its capacity to synthesize all major classes of steroids (Falco et al 2007;Harvey and Everett 2003;Hinson and Raven, 2006;Rosol et al 2001).…”

“…The adrenal gland is one of the most common target for chemically induced lesions (Rosol et al 2001). Because of several characteristics as: its large blood supply, its lipophilicity (allowing the accumulation of lipophilic compounds), its high concentration of cytochrome P450 that can also bioactivate toxicants, and its capacity to synthesize all major classes of steroids (Falco et al 2007;Harvey and Everett 2003;Hinson and Raven, 2006;Rosol et al 2001). Adrenal cells concentrate a number of toxic agents, as DDT (Lund et al 1988) and PCB metabolites (Brandt and Bergman, 1987) that may remain inactive caught into the adrenal tissue until a period of particularly high adrenal steroid demand, as the breeding period.…”

Mechanisms involved in regulation of Systemic Blood Pressure

“…The adrenal medulla is unique in that the gland is innervated by preganglionic SNS fi bres which originate directly from the spinal cord [25]. The adrenal medulla secretes adrenaline and NA in response to stimulation and function as hormones by entering the bloodstream and exerting distant effects on target organs.…”