In:
Acta Endocrinologica, Oxford University Press (OUP), Vol. 114, No. 3 ( 1987-03), p. 383-388
Abstract:
Abstract. The effect of β-endorphin, met-enkephalin and leu-enkephalin on cold-stimulated TSH and prolactin secretion after infusion of the drugs into the 3rd ventricle or into the posterior hypothalamus (PH) was investigated in male rats. β-endorphin (0.25 μg/rat, but not 0.05, 0.5 and 1 μg/rat) increased and met-enkephalin (20 and 100 μg/rat) decreased TSH secretion when infused into the 3rd ventricle. After bilateral infusion into the PH, β-endorphin (0.25 μg/side, but not 0.05 and 1 μg/side) increased TSH secretion, but met-enkephalin (1 and 10 μg/side) induced no changes. β-endorphin (0.05–1 μg/rat) and met-enkephalin (100 μg/rat) both increased prolactin secretion when infused into the 3rd ventricle, but only a high dose of β-endorphin (1 μg/side) was effective after infusion into the PH. Leu-enkephalin had no effect on TSH or prolactin secretion at the hypothalamic level. These results favour the hypothesis that μ-receptors mediate the inhibitory effect and other types (possible ε-receptors) of opiate receptors mediate the stimulatory effect of opioid peptides on TSH secretion at periventricular sites. However, only stimulatory μ-receptors affect prolactin secretion at these sites. After infusion into the PH, the effect of a high dose of β-endorphin on prolactin secretion may also be mediated through periventricular sites, but its effect on TSH secretion is evidently mediated through opiate receptors in the PH.
Type of Medium:
Online Resource
ISSN:
0804-4643
,
1479-683X
DOI:
10.1530/acta.0.1140383
Language:
Unknown
Publisher:
Oxford University Press (OUP)
Publication Date:
1987
detail.hit.zdb_id:
1485160-X
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