INVESTIGADORES
BELGOROSKY Alicia
artículos
Título:
Expression of the IGF and the aromatase/estrogen receptor systems in human adrenal tissues from early infancy to late puberty: implications for the development of adrenarche
Autor/es:
BELGOROSKY, A; BAQUEDANO,MS ;; GUERCIO G.,; RIVAROLA, MA.
Revista:
REVIEWS IN ENDOCRINE & METABOLIC DISORDERS
Editorial:
SPRINGER
Referencias:
Año: 2009 vol. 10 p. 51 - 61
ISSN:
1389-9155
Resumen:
Adrenarche is a process of postnatal sexual maturation occurring in higher
primates, in which there is an increase in the secretion of adrenal androgens. It
is the consequence of a process of postnatal organogenesis characterized by
the development of a new zone in the adrenal cortex, the zona reticularis (ZR).
The mechanism of this phenomenon remains poorly understood, suggesting
that it might be a multifactorial event. A relationship between circulating IGF-I,
insulin sensitivity, and adrenal androgens has been postulated. Boys and girls
have different patterns of changes in insulin sensitivity at puberty, perhaps
secondary to differences in the estrogen milieu. Estrogen effects may also play
a role in premature adrenarche. Peripheral or local IGF-1 actions could regulate
adrenal progenitor cell proliferation and migration. Since adrenal progenitor
cells as well as IGF-I and the IGF-R1 are located in the outer zone of the
adrenal cortex during childhood and adolescence, this peripheral cell layer,
below the capsule, may contain undifferentiated progenitor cells. Therefore, the
IGF-R1 signaling pathway might positively modulate the proliferation and
migration of adrenal progenitor cell to stimulate the development of adrenal
zones, including ZR. However, no evidence of a direct action of IGF-I on ZR
was found. In addition, a role for estrogens in the ontogenesis of ZR is
suggested by the presence of aromatase (CYP19) in the subcapsular zona
glomerulosa and in the adrenal medulla. Estrogens produced locally could act
on ZR by interacting with estrogen receptor beta (ERâ), but not alpha, and
membrane estrogen receptor GPR-30. An estradiol-induced increase in
DHEA/cortisol ratio was indeed seen in cultures of adrenocortical cells from
post-adrenarche adrenals. In summary, several lines of evidence point to the
action of multiple factors, such as local adrenal maturational changes and
peripheral metabolic signals, on postnatal human adrenal gland ZR formation.