Volume 5 Issue 2, December 1995: 197-207
ORIGINAL ARTICLES
Substance P enhances the proliferation of rat anterior pituitary cells in vitro.
ZHANG WANHUI, YUNLONG ZHU, FUZHOU WANG, YUZHEN HU, QI MEI, CHAO ZHAO, JINGKANG CHEN.
Laboratory of Neuroendocrinology, Department of Physiology, The 4th Military University, Xi’an 710032,China.
Correspondence: ZHANG WANHUI
The undecapeptide substance P(SP) was shown to be intimately involved in both the structural and functional aspects of the anterior pituitary. Yet, in addition to its influences on hormonal secretion, SP ay well possess more actions in this master gland. The present study was therefore aimed to investigate the effect of SP on the proliferation of rat anterior pituitary cells in primary culture. It was found that SP could dose-dependently increase the incorporation of tritiated thymidine (3H-TdR) in to cultured anterior pituitary cells. Other mammalian tachykinins such as neurokinin A and neurokinin B had similar effect but to varying degrees. The equipotent analogue of SP, Norleucine11-SP(Nle11-SP), also acted like-wise, with its action antagonizable by spantide, a SP receptor blocker. To further characterize the nature of cells responsive to the challenge of SP, immunocytochemical staining against S-100 protein and some adenohypophyseal hormones was performed alone of plus autoradiography. The results showed that the percentage of S-100 protein immunoreactive cells was apparently elevated by the addtion of Nle11-SP for 48h, which indicates a preferential proliferation of folliculo-stellate cells under the regime. This was confirmed by increases in immunocytochemical or autoradiographical labeling indices of anterior pituitary cells treated similarly. Taken together, these results reveal that the trophic action of SP observed previously in other tissues is also present at least in cultured rat anterior pituitary cells, with responding cells being predominantly folliculo-stellate cells as typified by S-100 protein-immunoreactivity. Therefore, an intra-pituitary trophic action of SP in vivo could be anticipated.
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