Detail of "1821-47-2"

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5-Hydroxytryptamine stimulates inositol phosphate production in a cell-free system from blowfly salivary glands

5-Hydroxytryptamine stimulates inositol phosphate production in a cell-free system from blowfly salivary glands. Evidence for a role of GTP in coupling receptor activation to phosphoinositide breakdown. Litosch, Irene; Wallis, Christopher; Fain, John N. (Dep. Biochem., Brown Univ., Providence, RI 02912, USA). J. Biol. Chem., 260(9), 5464-71 (English) 1985. CODEN: JBCHA3. ISSN: 0021-9258. DOCUMENT TYPE: Journal CA Section: 2 (Mammalian Hormones) In a cell-free system prepd. from [3H]inositol-labeled blowfly salivary glands, 5-hydroxytryptamine (I) [50-67-9] stimulated the rapid prodn. of inositol phosphates. Within 30 s of I addn., there was a 100% increase in inositol trisphosphate [27121-73-9] formation, a 70% increase in inositol bisphosphate [27216-57-5] formation, and a 90% increase in inositol monophosphate [15421-51-9] formation as compared to control homogenates incubated for the same length of time. I did not stimulate inositol or glycerol phosphoinositol formation. Half-maximal activation of inositol phosphate prodn. was obtained with 0.33 mM I. EGTA (0.3 mM) inhibited the basal formation of inositol phosphates and decreased the net accumulation of inositol bisphosphate and inositol trisphosphate due to I as compared to homogenates incubated in the absence of added Ca2+. EGTA, however, had little effect on the per cent stimulation of inositol phosphate prodn. due to I. In homogenates, ATP [56-65-5], GTP [86-01-1], or guanyl-5'-yl imidodiphosphate (Gpp(NH)p) [34273-04-6] was required for a hormone effect. Gpp(NH)p, unlike ATP or GTP, increased the basal formation of inositol phosphates. In membranes, GTP, Gpp(NH)p, or guanosine 5'-(3-O-thio)trisphosphate (GTPgS) [37589-80-3] sustained a hormone effect whereas ATP was ineffective. GTP did not affect prodn., whereas Gpp(NH)p and GTPgS increased inositol phosphate prodn. Half-maximal effects of Gpp(NH)p and GTPgS on I-stimulated inositol phosphate formation occurred at 10 mM and 100 nM, resp. In the presence of 1 mM GTPgS, 5-methyltryptamine [1821-47-2] stimulated inositol phosphate formation within 2 s in membranes. In a cell-free system, GTP is apparently involved in mediating the effects of Ca2+-mobilizing hormones on phosphoinositide breakdown.