INVESTIGADORES
GIOVAMBATTISTA Andres
artículos
Título:
Gender-dependent characteristics of the hypothalamo-corticotrope axis function in glucocorticoid-replete and glucocorticoid-depleted rats.
Autor/es:
CHISARI, A; PERONE M; GIOVAMBATTISTA A; SPINEDI, E
Revista:
JOURNAL OF ENDOCRINOLOGICAL INVESTIGATION
Editorial:
..
Referencias:
Año: 1998 vol. 21 p. 737 - 743
ISSN:
0391-4097
Resumen:
The aim of the present study was to determine the role of the endogenous
sex steroid environment in the hypothalamo-corticotrope (HC) function in both
sham-operated (SHAM) and bilaterally adrenalectomized (ADX) rats. For this
purpose adult rats of both sexes were used 3 and 6 weeks after either SHAM or
ADX. The results indicate that: a) in SHAM animals, basal plasma ACTH levels
were significantly higher in females than in males, and this sexual dimorphism
was overridden by ADX, regardless of the time post-surgery; b) although basal
anterior pituitary (AP) ACTH content was similar in SHAM animals of both sexes,
3- and 6-week ADX induced higher AP ACTH in males than in females; c) at 3- and
6-weeks, ADX rats of hoth sexes had an AVP:CRH ratio (r), in the median
eminence (ME) and medial basal hypothalamus (MBH), increased several fold over
the respective SHAM-value and, although no sexual dimorphism was found at week
3 post-ADX, by 6-weeks post ADX, these ratios were significantly higher in both
brain tissues of females than in those of males; and d) the in vitro ME CRH and
AVP output in response to high potassium concentrations (hK+; 28 and 56
mmol/I), was concentration-related, regardless of sex and surgery, and was
characterized by enhanced secretion of neuropeptides by MEs from ADX in
comparison to SHAM rats of both sexes, and a sexual dimorphism was found in
this parameter, consisting in general, in greater neuropeptide output from
tissues of female than of male animals. Our results indicate that: 1) there is
a gender-dependent characteristic of the HC axis function in glucocorticoid-replete
rats and 2) the absence of the glucocorticoid negative feedback mechanism is
responsible for either the expression or for the override of the sexual
dimorphism in different parameters, a phenomenon which dependent on the time
elapsed after ADX.