Inositol lipid turnover and adenosine 3,5 cyclic monophosphate in the salt-secreting rectal gland of the dogfish (Scyliorhinus canicula).
The rectal gland of the dogfish is rich in inositol lipids. Total phospholipids from the gland contained 9.1 mol% of phosphatidylinositol (PtdIns), 1.0 mol% of phosphatidylinositol 4-phosphate (PtdIns4P) and 0.9 mol% of phosphatidylinositol 4,5-biphosphate (PtdIns4,5P2). [32P]Orthophosphate was readily incorporated into PtdIns, phosphatidic acid (PtdA) and especially into PtdIns4P and PtdIns4,5P2 in salt gland slices incubated in elasmobranch Ringer with glucose and no other additions over a 2 hr period. The calcium ionophore A23187 stimulated incorporation into PtdIns and PtdA, but not into PtdIns4P or PtdIns4,5P2. Oxygen uptake by rectal gland slices was maximally stimulated by 0.08mM forskolin, 2.5mM 8-chlorophenylthio cyclic AMP, 2.0mM dibutyryl cyclic AMP and 0.25mM theophylline. Stimulated oxygen uptake was inhibited by 0.1mM ouabain in all cases. Incorporation of [32P]orthophosphate into PtdIns, PtdA, PtdIns4P and PtdIns4,5P2 was inhibited by 0.08mM forskolin and 2.0mM dibutyryl cyclic AMP over a 2 hr period. The results are discussed in relation to the control of salt secretion by the rectal gland.
D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D004284:Dogfish; D066298:In Vitro Techniques; D007700:Kinetics; D010710:Phosphates / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D010761:Phosphorus Radioisotopes; D012491:Salt Gland / Q000378:metabolism; D012965:Sodium Chloride / Q000378:metabolism; D013806:Theophylline / Q000494:pharmacology; D013873:Thionucleotides / Q000494:pharmacology
D010710:Phosphates; D010716:Phosphatidylinositols; D010743:Phospholipids; D010761:Phosphorus Radioisotopes; D013873:Thionucleotides; D005576:Colforsin; D000001:Calcimycin; C015929:8-((4-chlorophenyl)thio)cyclic-3',5'-AMP; D012965:Sodium Chloride; D003994:Bucladesine; D013806:Theophylline; D000242:Cyclic AMP