Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Growth hormone-releasing factor (GRF) and vasoactive intestinal peptide (VIP) are two structurally homologous peptides sharing common target cell receptor and known to enhance FSH-induced steroidogenesis of undifferentiated granulosa cell in vitro. Although VIP, has been reported to stimulate plasminogen activator (PA) activity in rat granulosa cells, our knowledge on the actions and interactions of these two peptides with FSH in the regulation of rat granulosa cell PA system during follicular development remains incomplete. Undifferentiated and differentiated rat granulosa cells from pre-antral (DES-treated rats) and antral (eCG-treated rats) follicles, respectively, were cultured in a chemically defined medium in the absence and presence of FSH (400 ng/ml), GRF (10(-8)-10(-5) M) and/or VIP (10(-9)-10(-5) M). Net secreted (PAs) and cell-associated (PAc) PA activities was measured by the fibrinolysis assay and characterized by the fibrin overlay method. Granulosa cell differentiative (progestin secretion) and proliferative (DNA synthesis) responses were analyzed by radioimmunoassay and [3H]thymidine incorporation, respectively. Both GRF and VIP stimulated PAs and PAc activities in a concentration-dependent manner in 24-h cultures of granulosa cells from the two stages of follicular development. They (10(-5) M) enhanced FSH-stimulated PAs activity in granulosa cell cultures of pre-antral follicles, with GRF being more effective than VIP. On the contrary, only GRF (10 microM) potentiated FSH-induced PAs and PAc activities in cultures of granulosa cell from antral follicles. The stimulation of PA activity by these agonists decreased with the duration of culture irrespective of the stage of follicular development.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Growth hormone releasing factor and vasoactive intestinal peptide stimulate rat granulosa cell plasminogen activator activity in vitro during follicular development. 779 29

The basal in vitro release of amylase was similar from rat parotid lobules of innervated and chronically denervated glands and was unaffected by the inhibitors used in this study. The secretion of amylase induced by isoprenaline or vasoactive intestinal peptide (VIP) was reduced by one-third to one-half from the lobules of the innervated glands and even more so from the lobules of the denervated glands by ODQ, an inhibitor of soluble guanyl cyclase which is activated by nitric oxide (NO) and catalyses the cGMP production. The use of N (omega)-propyl-L-arginine (N-PLA) revealed that the evoked secretion of amylase in the denervated glands depended on the activity of neuronal type NO synthase to synthesize NO. Since the denervated gland is virtually devoid of NO synthase-containing nerve fibres, the neuronal type NO synthase was most probably of a non-neuronal source. NO-dependent amylase secretion was agonist related, since amylase secretion evoked by bethanechol and neuropeptide Y was not reduced by ODQ or N-PLA. Hence, under physiological conditions, activation of beta-adrenoceptors (sympathetic activity) and VIP receptors (parasympathetic activity) is likely to cause secretion of parotid amylase partly through a NO/cGMP-dependent intracellular pathway involving the activity of neuronal type NO synthase, possibly of acinar origin.
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PMID:Nitric oxide-dependent in vitro secretion of amylase from innervated or chronically denervated parotid glands of the rat in response to isoprenaline and vasoactive intestinal peptide. 1271 62

The external layer of the median eminence is comprised of nerve fibres that terminate on the primary plexus of the hypophysial portal vessels. This system is a unique neurovascular synapse which can be used as a window through which may be studied the characteristics of central neurotransmission. The heterogeneity of the neuropil of the external layer of the median eminence, in terms of neurotransmitter types, carries the advantage that interactions between different classes of neurons can be investigated. These points are illustrated by physiological and pharmacological studies on the release into hypophysial portal blood of several neuropeptides including luteinizing hormone releasing hormone, thyrotrophin releasing hormone, vasoactive intestinal peptide, somatostatin 14, 28 and (1-12) 28, vasopressin and oxytocin. The portal vessels convey these neurohormones to the anterior pituitary gland where they stimulate or inhibit the release of pituitary hormones. The way in which the pituitary gland may be used to investigate the "post synaptic" effects of neuropeptides is illustrated with special reference to luteinizing hormone releasing hormone. In addition to the "established" neurohormones, attention is also focused on a recently discovered hypothalamic pituitary system that controls the release of plasminogen activator and on thyrocalcitonin and the calcitonin gene related peptide which demonstrate the way in which studies of the hypothalamus have led to the discovery of new neural control mechanisms.
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PMID:The external layer of the median eminence: A neurovascular synapse. 2049 12