Cytokine Expression in the Rat Adrenal Cortex

The rat adrenal cortex produces the cytokines interleukin-6, tumor necrosis factor, interleukin-1β, interleukin-1α, macrophage migration inhibitory factor, interferon-gamma inducing factor, and transforming growth factor-β₁. Interleukin-6, tumor necrosis factor, and macrophage migration inhibitory factor are localized to the zona glomerulosa. In contrast, interferon-gamma inducing factor is localized to the zona reticularis and fasciculata. Transforming growth factor-β₁ is localized to the zona fasciculata. Endotoxin and interleukin-1 increase interleukin-6 and tumor necrosis factor release from adrenal cells. In contrast, adrenocorticotrophic hormone, adenosine, serotonin, and dopamine increase adrenal interleukin-6 release, but inhibit tumor necrosis factor release. These secretagogues also increase interleukin-6 mRNA content of adrenal cells. Adrenocorticotrophic hormone decreases transforming growth factor β₁ content of adrenal glands. Endotoxin increases adrenal expression of mRNA for macrophage migration inhibitory factor, but decreases the tissue content of this protein. Endotoxin increases the expression of interleukin-1β mRNA. Cold stress increases the expression of mRNA for interferon-gamma inducing factor. Therefore, cytokines are differentially expressed in the adrenal cortex and the release and production of these cytokines are regulated selectively. Because cytokines have effects on adrenal function and are differentially regulated, they may play autocrine/paracrine roles in regulating the adrenal gland.

Key words

Interleukin-1 - Interleukin-6 - Tumor Necrosis Factor - Endotoxin