Role of calcium ion in hormone-stimulated lipolysis.
Using the flask-incubated fat cell system, the effects of Ca2+ removal from the incubation medium on the lipolytic system were studied. The removal of Ca2+ resulted in a total abolition of the lipolytic response and the increased cyclic AMP accumulation produced by ACTH. The lipolytic response to isoproterenol and forskolin were reduced approximately 40% by Ca2+ removal, but cyclic AMP accumulation was not altered in the presence of either of these agents using a Ca2+-free medium. The lipolytic response to the dibutyryl analog of cyclic AMP was also reduced by omission of Ca2+ from the incubation medium. It is concluded the Ca2+ is required for the interaction of ACTH with its receptor and the resultant activation of adenylate cyclase. Ca2+ also is required at some step in the lipolytic process distal to cyclic AMP.
D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000502:physiology*; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005990:Glycerol / Q000378:metabolism; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D007700:Kinetics; D008053:Lipid Mobilization / Q000187:drug effects*; D008297:Male; D051381:Rats
D005576:Colforsin; D000324:Adrenocorticotropic Hormone; D000242:Cyclic AMP; D007545:Isoproterenol; D005990:Glycerol; D002118:Calcium