Adrenal steroid-secreting cells express endothelin-1

Endothelin-1 (ET-1) is involved in adrenal steroid secretion but its cell origin remains unclear. We showed, using RT-PCR the expression of the mRNAs for preproET-1 and ECE-1 in primary cultures of human adrenal cells enriched in glomerulosa cells. Since these expressions could be due to contamination of steroid secreting cells by other cells, we also used the human adrenocortical cell line H295R, which was shown to produce steroids. This cell line also expressed preproET-1-RNA and released mature ET. Functional ET receptors were shown on H295R and cultured human adrenocortical cells. These findings indicate that adrenal steroid-secreting cells synthesize and release ET-1, raising the possibility for an autocrine-paracrine effect of ET-1 on adrenocortical functions.