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Sexual Dimorphism in the Distribution of a‐Neoendorphin‐Like Immunoreactivity in the Anterior Pituitary of the Rat
Author(s) -
Bello Aixa R.,
Kah Olivier,
Croix Dominique,
Ciofi Philippe,
Tramu Gérard
Publication year - 1993
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1111/j.1365-2826.1993.tb00488.x
Subject(s) - medicine , endocrinology , gonadotropic cell , thyrotropic cell , anterior pituitary , castration , luteinizing hormone , biology , immunostaining , corticotropic cell , testosterone (patch) , follicle stimulating hormone , hormone , sexual dimorphism , immunohistochemistry
The localization of the opioid peptide α‐neoendorphin (α‐Neo‐E) was studied in the anterior pituitary of normal and castrated male and normal female rats, Immunoreactive (ir) cells were noted in both sexes. These α‐Neo‐E‐ir cells were further characterized using double immunostaining with an elution‐restaining procedure. It was seen that in males, α‐Neo‐E‐ir cells corresponded mainly to luteinizing hormone/follicle‐stimulating hormone cells and a few thyroid‐stimulating hormone (TSH) cells, whereas in females, virtually all α‐Neo‐E‐ir cells corresponded to TSH cells. Castration of male rats caused, within 3 to 5 days, a dramatic decrease in the number of α‐Neo‐E‐ir gonadotrophs, whereas the number of a‐Neo‐E‐ir TSH cells tended to increase. Two weeks after castration, however, most α‐Neo‐E‐ir cells were also follicle‐stimulating hormone‐ir. This study demonstrates that in the anterior lobe of the rat, α‐Neo‐E‐ir is located within gonadotrophs and/or thyrotrophs, depending on the sex. In addition, results obtained following castration suggest that the expression of this peptide in the anterior pituitary depends upon the steroid environment, possibly indicating that α‐Neo‐E is implicated in the regulation of the pituitary‐gonadal axis.