Abstract
Vasoactive intestinal peptide (VIP) is a prolactin-releasing hormone which is involved in the multifactorial modulation of prolactin secretion in mammals. Intravenous injection of VIP (1 μg/kg) to fertile women increased plasma prolactin levels and heart rate and reduced diastolic pressure. The same treatment to menopausal women caused similar cardiovascular effects but did not modify prolactin levels. In contrast, TRH (200 μg, i.v.) induced a significant increase in plasma prolactin levels in both fertile and menopausal women. The relevance of oestrogens in affecting VIP-stimulated prolactin secretion was evaluated in vitro by measuring prolactin release from pituitary cells of control and ovariectomized rats. The sensitivity of rat mammotrophs to VIP, but not to TRH, was completely suppressed 3 or 4 weeks after ovariectomy. Furthermore, implantation of rats with a silastic capsule containing oestradiol-17β during ovariectomy, preserved the cell responsiveness to VIP. The prolactin-releasing property of VIP was also restored when pituitary cells from ovariectomized rats were cultured for 3 days in the presence of 10 nmol oestradiol-17β/l before being used for prolactin release experiments. The present study shows that the ability of prolactin-secreting cells to respond to the stimulatory action of VIP requires high levels of circulating oestrogens, both in man and rats.
| Original language | English |
|---|---|
| Pages (from-to) | 311-316 |
| Number of pages | 6 |
| Journal | Journal of Endocrinology |
| Volume | 132 |
| Issue number | 2 |
| Publication status | Published - 1992 |
Fingerprint
ASJC Scopus subject areas
- Endocrinology
Cite this
Requirement of oestrogens for the sensitivity of prolactin cells to vasoactive intestinal peptide in rats and man. / Pizzi, M.; Rubessa, S.; Simonazzi, E.; Zanagnolo, V.; Falsetti, L.; Memo, M.; Spano, P. F.
In: Journal of Endocrinology, Vol. 132, No. 2, 1992, p. 311-316.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Requirement of oestrogens for the sensitivity of prolactin cells to vasoactive intestinal peptide in rats and man
AU - Pizzi, M.
AU - Rubessa, S.
AU - Simonazzi, E.
AU - Zanagnolo, V.
AU - Falsetti, L.
AU - Memo, M.
AU - Spano, P. F.
PY - 1992
Y1 - 1992
N2 - Vasoactive intestinal peptide (VIP) is a prolactin-releasing hormone which is involved in the multifactorial modulation of prolactin secretion in mammals. Intravenous injection of VIP (1 μg/kg) to fertile women increased plasma prolactin levels and heart rate and reduced diastolic pressure. The same treatment to menopausal women caused similar cardiovascular effects but did not modify prolactin levels. In contrast, TRH (200 μg, i.v.) induced a significant increase in plasma prolactin levels in both fertile and menopausal women. The relevance of oestrogens in affecting VIP-stimulated prolactin secretion was evaluated in vitro by measuring prolactin release from pituitary cells of control and ovariectomized rats. The sensitivity of rat mammotrophs to VIP, but not to TRH, was completely suppressed 3 or 4 weeks after ovariectomy. Furthermore, implantation of rats with a silastic capsule containing oestradiol-17β during ovariectomy, preserved the cell responsiveness to VIP. The prolactin-releasing property of VIP was also restored when pituitary cells from ovariectomized rats were cultured for 3 days in the presence of 10 nmol oestradiol-17β/l before being used for prolactin release experiments. The present study shows that the ability of prolactin-secreting cells to respond to the stimulatory action of VIP requires high levels of circulating oestrogens, both in man and rats.
AB - Vasoactive intestinal peptide (VIP) is a prolactin-releasing hormone which is involved in the multifactorial modulation of prolactin secretion in mammals. Intravenous injection of VIP (1 μg/kg) to fertile women increased plasma prolactin levels and heart rate and reduced diastolic pressure. The same treatment to menopausal women caused similar cardiovascular effects but did not modify prolactin levels. In contrast, TRH (200 μg, i.v.) induced a significant increase in plasma prolactin levels in both fertile and menopausal women. The relevance of oestrogens in affecting VIP-stimulated prolactin secretion was evaluated in vitro by measuring prolactin release from pituitary cells of control and ovariectomized rats. The sensitivity of rat mammotrophs to VIP, but not to TRH, was completely suppressed 3 or 4 weeks after ovariectomy. Furthermore, implantation of rats with a silastic capsule containing oestradiol-17β during ovariectomy, preserved the cell responsiveness to VIP. The prolactin-releasing property of VIP was also restored when pituitary cells from ovariectomized rats were cultured for 3 days in the presence of 10 nmol oestradiol-17β/l before being used for prolactin release experiments. The present study shows that the ability of prolactin-secreting cells to respond to the stimulatory action of VIP requires high levels of circulating oestrogens, both in man and rats.
UR - http://www.scopus.com/inward/record.url?scp=0026557272&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0026557272&partnerID=8YFLogxK
M3 - Article
VL - 132
SP - 311
EP - 316
JO - Journal of Endocrinology
JF - Journal of Endocrinology
SN - 0022-0795
IS - 2
ER -