DEVELOPMENTAL CHANGES IN THE EXPRESSION OF AROMATASE (ARO), ESTROGEN RECEPTOR (ER) AND ALTERNATIVE EXON 1 OF ARO GENE IN PREPUBERTAL AND PUBERTAL HUMAN ADRENAL TISSUES (HAT)

BAQUEDANO MS, SARACO N, BERENSZTEIN E, PEPE C, RIVAROLA M, BELGOROSKY A

Viña del Mar, Chile.

Congreso; XVIII Reunión de la Sociedad Latinoamericana de Endocrinología Pediátrica; 2006

Sociedad Latinoamericana de Endocrinología Pediátrica (SLEP)

The postnatal adrenal zonation remains unclear. To provide a clue to the cellular function of Estrogen (Es) at adrenarche, we studied the expression of ERa, ERâ and ARO in HAT HAT were divided in 3 postnatal age groups: Gr1 <3m, n=13, fetal zone (FeZ) involution period; Gr2 3m to 6yr, n=13, pre-adrenarche; and Gr3 >6yr to 20yr, n=11, adrenarche ERâ mRNA in Gr3 (1.54±0.34 AU) was higher than in Gr2 (0.79±0.28), p<0.05, while in Gr1 was variable. By Immunohistochemistry, ERâ was restricted to zona reticularis (ZR) and FeZ but ERa mRNA and protein were undetectable in HAT ARO mRNA in Gr3 (1.79±0.73) was higher than in Gr1 (0.99±0.29) and Gr2 (1.17±0.61), p<0.05. Strong ARO immunostained signal was observed in AM in the 3 Gr and in zona glomerulosa (ZG) of Gr3. Double immunofluorescence studies revealed that ARO and chromogranin A only colocalize in AM of subjects younger than 2 yr old. In this samples exon 1.b and 1.6-derived transcripts were 3.5 and 1.2-fold higher than in Gr3, while 1.a, 1.c and 1.d-derived transcripts increased 3.3, 1.9 and 1.7-fold in Gr3, respectively. In addition, E2 (0.1µM) stimulated DHEAS production in human adrenal cell cultures. Our results suggest that Es produced locally in AM, would play a role in the regulation of ZR functional differentiation throughout ERâ The high ARO expression in ZG, colocalizing with a high cell proliferation index previously reported, might suggest a local ER-independent Es action in proliferation and migration of progenitor adrenal cells. A switch in promoter utilization with age is suggested. Finally, the implicancy of the developmental changes of ARO expression in chromaffin cells has to be elucidated.