title: Expression of the mu-opioid receptor in the anterior pituitary gland is influenced by age and sex.
abstract: To analyze whether opioids are able to modulate endocrine regulation by acting directly on rat pituitary cells, an immunohistochemical study of micro-opioid receptor expression in these cells was performed, with attention given to the analysis of potential age- and sex-related variations in receptor expression patterns. In both sexes, the micro-opioid receptor was detected in the pituitary pars distalis. However, significant age-related differences were observed. Both in male and female rats, the percentage of micro-opioid receptor-expressing cells decreased significantly from postnatal week one through the 24 months of our study. Interestingly, pituitary cells containing the micro-opioid receptor were significantly more numerous in male than in female, with exception of the pre-pubertal phase and old rats. According to two-way analysis of variance, the gender-related differences in micro-receptor expression were independent of age-related variations. Thus, without excluding hypothalamic actions, our results suggest that opioids may exert their endocrine function by acting directly on pituitary cells.
authors.affiliation: Department of Human Anatomy and Histology, Lab. Neuroendocrinología experimental y Diabetes, InCyL, Faculty of Medicine, University of Salamanca, Avda. Alfonso X el Sabio, s/n, E-37007, Spain. jcar@gugu.usal.es
authors.forename: J
authors.initials: J
authors.lastname: Carretero
authors.forename: P
authors.initials: P
authors.lastname: Bodego
authors.forename: R E
authors.initials: RE
authors.lastname: Rodríguez
authors.forename: M
authors.initials: M
authors.lastname: Rubio
authors.forename: E
authors.initials: E
authors.lastname: Blanco
authors.forename: D J
authors.initials: DJ
authors.lastname: Burks
mesh_terms: D000367:Age Factors; D000818:Animals; D005260:Female; D007150:Immunohistochemistry; D008297:Male; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D017450:Receptors, Opioid, mu / Q000096:biosynthesis*; D012737:Sex Factors
chemical_list: D017450:Receptors, Opioid, mu