PubMed · 169207
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T G Brien, D J Hingerty. 1975. The free cortisol index.. https://pubmed.ncbi.nlm.nih.gov/169207/
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Vascular endothelial growth factor (VEGF), also known as vascular permeability factor or vasculotropin, is a recently characterized endothelial-specific mitogen which is angiogenic in vivo. Here we demonstrate that VEGF is angiogenic in vitro: when added to microvascular endothelial cells grown on the surface of three-dimensional collagen gels, VEGF induces the cells to invade the underlying matrix and to form capillary-like tubules, with an optimal effect at approximately 2.2nM (100ng/ml). When compared to basic fibroblast growth factor (bFGF) at equimolar (0.5nM) concentrations, VEGF was about half as potent. The most striking effect was seen in combination with bFGF: when added simultaneously, VEGF and bFGF induced an in vitro angiogenic response which was far greater than additive, and which occurred with greater rapidity than the response to either cytokine alone. These results demonstrate that like bFGF, VEGF induces an angiogenic response via a direct effect on endothelial cells, and that by acting in concert, these two cytokines have a potent synergistic effect on the induction of angiogenesis in vitro. We suggest that the synergism between VEGF and bFGF plays an important role in the control of angiogenesis in vivo.
Galanin, a 28-amino-acid peptide originally isolated from pig intestine, was found to cause dose-dependent rises in the plasma concentration of corticosterone in hypophysectomized rats and in both basal and submaximally ACTH-stimulated in vitro corticosterone production by adrenal quarters and isolated zona fasciculata/reticularis cells. These findings indicate that galanin exerts a direct glucocorticoid secretagogue effect on the inner adrenocortical zones and suggest that galanin, high concentrations of which are contained in adrenal chromaffin cells, may be included in that group of regulatory peptides, by way of which adrenal zona medullaris is thought to exert a paracrine control on the function of the zona corticalis. Galanin was also found to increase the plasma level of aldosterone in hypophysectomized rats in a dose-dependent manner without inducing changes in natremia, kalemia, plasma renin activity, or ACTH plasma concentration. Galanin did enhance both basal aldosterone output and that following submaximal ACTH or angiotensin II stimulation aldosterone output from adrenal quarters, but not from isolated zona glomerulosa cells. This last, rather unexpected, result suggests that galanin exerts an indirect mineralocorticoid secretagogue action, which seems to require the structural integrity of the adrenal cortex and the presence of the adrenal medulla. The hypothesis is advanced that galanin may control the release of some medullary peptides, which in turn may affect mineralocorticoid secretion of the zona glomerulosa in a paracrine manner.
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