Estrogen modulates neuromedin B effects on thyrotropin and prolactin release in vitro

Estrogen modulates neuromedin B effects on thyrotropin and prolactin release in vitro

Neuromedin B(NB), a bombesin-like peptide, has been shown to inhibit thyrotropin (TSH) release in pituitary explants of male rats and to stimulate Prolactin (PRL) release in male pituitary cell cultures. We investigated the effect of estrogen status of female rats on the response of thyrotrophs and...

Full description

Saved in:
Bibliographic Details
Published in:Life sciences (1973) Vol. 72; no. 8; pp. 917 - 923
Main Authors: Moreira, Rachel Moraes, Curty, Flavio Henrique, Lisboa, Patricia Cristina, Amaral, Daniele, Ortiga-Carvalho, Tania Maria, Pazos-Moura, Carmen C
Format: Journal Article
Language:English
Published: Netherlands Elsevier Inc 10-01-2003
Subjects:
Animals
Dose-Response Relationship, Drug
Drug Antagonism
Estradiol - analogs & derivatives
Estradiol - pharmacology
Estrogen
Female
In Vitro Techniques
Neurokinin B - analogs & derivatives
Neurokinin B - metabolism
Neuromedin B
Ovariectomy
Pituitary Gland, Anterior - drug effects
Pituitary Gland, Anterior - metabolism
Prolactin
Prolactin - metabolism
Radioimmunoassay
Rats
Thyrotropin
Thyrotropin - metabolism
Thyrotropin
Neuromedin B
Prolactin
Estrogen
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Neuromedin B(NB), a bombesin-like peptide, has been shown to inhibit thyrotropin (TSH) release in pituitary explants of male rats and to stimulate Prolactin (PRL) release in male pituitary cell cultures. We investigated the effect of estrogen status of female rats on the response of thyrotrophs and lactotrophs to neuromedin B (NB) in vitro. Ovariectomized rats were treated with near-physiological or high doses of 17β estradiol benzoate (0.7 or 14 EB μg/100 gBW/daily, 10 days) or with vehicle (OVX). EB treatment induced a dose-dependent increase in serum prolactin and an increase in pituitary NB content, measured by specific RIA, that was similar in both EB groups (P < 0.05). TSH release from isolated hemipituitaries of OVX rats was significantly reduced (P < 0.05) in the presence of 10 −7 M NB. OVX + EB0.7 glands responded to NB with a not statistically significant dose-dependent decrease in TSH release. However, glands from hyperestrogenized rats (OVX + EB14) required a higher dose (10 −5 M) of NB to inhibit TSH release (P < 0.05). PRL release was highly increased (p < 0.001) by the presence of 10 −5 M NB only in glands of hyperestrogenized rats, while no effect of NB was observed in the other groups. In conclusion, estrogen status of female rats modulates the inhibitory effect of NB on TSH release in vitro and hyperestrogenism is required for stimulatory effect of NB on PRL release in vitro. It is suggested that the induction of PRL release by neuromedin B is a pharmacological rather than a physiological effect, but neuromedin B may contribute to the increased release of PRL associated with hyperestrogenism.
ISSN:0024-3205
1879-0631
DOI:10.1016/S0024-3205(02)02351-2