Median eminence lesions reveal separate hypothalamic control of pulsatile follicle-stimulating hormone and luteinizing hormone release.
Proc Soc Exp Biol Med
; 220(3): 139-46, 1999 Mar.
Article
em En
| MEDLINE
| ID: mdl-10193441
The effects of hypothalamic lesions designed to destroy either the anterior median eminence (ME) or the posterior and mid-ME on pulsatile release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were determined in castrated male rats. In sham-operated animals, mean plasma FSH concentrations rose to peak at 10 min after the onset of sampling, whereas LH declined to a nadir during this time. In the final sample at 120 min, the mean FSH concentrations peaked as LH decreased to its minimal value. In rats with anterior ME lesions, there was suppression of LH pulses with continuing FSH pulses in 12 of 21 rats. On the other hand, in animals with posterior to mid-ME lesions, 3 out of 21 rats had elimination of FSH pulses, whereas LH pulses were maintained. Fifteen of 42 operated rats had complete ME lesions, and pulses of both hormones were abolished. The remaining 12 rats had partial ME lesions that produced a partial block of the release of both hormones. The results support the concept of separate hypothalamic control of FSH and LH release with the axons of the putative FSH-releasing factor (FSHRF) neuronal system terminating primarily in the mid- to caudal ME, whereas those of the LHRH neuronal system terminate in the anterior and mid-median eminence. We hypothesize that pulses of FSH alone are mediated by release of the FSHRF into the hypophyseal portal vessels, whereas those of LH alone are mediated by LHRH. Pulses of both gonadotropins simultaneously may be mediated by pulses of both releasing hormones simultaneously. Alternatively, relatively large pulses of LHRH alone may account for simultaneous pulses of both gonadotropins since LHRH has intrinsic FSH-releasing activity.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Hormônio Luteinizante
/
Hormônio Foliculoestimulante
/
Eminência Mediana
Limite:
Animals
Idioma:
En
Revista:
Proc Soc Exp Biol Med
Ano de publicação:
1999
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Estados Unidos