title: Melanophore stimulating hormone (MSH) release: inhibition by cytochalasin B and "stimulation" by dimethyl sulfoxide.
abstract: Incubation of rat or frog pituitaries in cytochalasin B (10-4 minus 10-8 g/ml) for 2, 4 or 6 hr produces a time-dependent inhibition of MSH release. This inhibition is reversible and, again, time-dependent since longer incubations of pituitaries returned to normal media result in greater hormone secretion. Cytochalasin B inhibits MSH release even at a high concentration (10%) of dimethylsulfoxide (DMSO) which, itself, is "stimulatory" to hormone release. MSH release in high DMSO concentration is also inhibited by ouabain or by the absence of Ca2+ from the medium. In amphibian Ringer enriched with glucose, and in Medium 199, cytochalasin B fails to inhibit the release of MSH from the frog pituitary. Colchicine, vinblastine, and vincristine (10-3 minus 10-6 g/ml) were without effect on MSH release. These data suggest a possible role for microfilaments in the control of MSH release but fail to provide information on the exact nature of the mechanisms involved.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology; D003078:Colchicine / Q000494:pharmacology; D003571:Cytochalasin B / Q000494:pharmacology*; D003864:Depression, Chemical; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D005260:Female; D005947:Glucose / Q000494:pharmacology; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D010902:Pituitary Gland / Q000378:metabolism*; D011894:Rana pipiens; D051381:Rats; D013268:Stimulation, Chemical; D013997:Time Factors; D014747:Vinblastine / Q000494:pharmacology; D014750:Vincristine / Q000494:pharmacology
chemical_list: D003571:Cytochalasin B; D010042:Ouabain; D014750:Vincristine; D014747:Vinblastine; D009074:Melanocyte-Stimulating Hormones; D005947:Glucose; D003078:Colchicine; D002118:Calcium; D004121:Dimethyl Sulfoxide