Bovine Neurophysin II Has Prolactin-Releasing Activity in the Estradiol-Primed Male Rat
作者:
Seon H. Shin,
Marc C. Obonsawin,
期刊:
Neuroendocrinology
(Karger Available online 1985)
卷期:
Volume 41,
issue 4
页码: 276-282
ISSN:0028-3835
年代: 1985
DOI:10.1159/000124190
出版商: S. Karger AG
关键词: Neurophysin II;Prolactin-releasing factor;Neurohypophysis;Prolactin
数据来源: Karger
摘要:
In the course of the search for the prolactin-releasing factor (PRF), we noticed that the posterior pituitary contained strong PRF activity and subsequently traced this activity to that of bovine neurophysin-II (NP-II). NP-II prepared in our lab was judged to be a homogeneous preparation according to Sephadex G-75 gel filtration, DEAE ion exchange chromatography and polyacrylamide gel electrophoresis. While neurophysin-I (NP-I) injections of 100 µg/kg and 1,000 µg/kg elevated plasma prolactin in estradiol-primed male rats to 30% and 50% over the control value, respectively, NP-II doses of 100, 1,000 µg/kg increased plasma prolactin concentration in estradiol-primed male rats to 130% and 170% over the control value, respectively. The lowest dose of NP-II needed to increase plasma prolactin concentration was 10 µg/kg. Since neurophysin does not stimulate prolactin release from the ectopic pituitary under the kidney capsule nor from lactotrophs in a primary monolayer culture system, neurophysin is believed to act indirectly on the pituitary, presumably through a neurotransmitter and/or hypothalamic releasing (or inhibiting) factor. We propose that NP-II may be one element in the complex chain of the prolactin-releasing mechan
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