help button home button Endocrine Society Endocrinology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Article
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Copyright Permission
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Login, I. S.
Right arrow Articles by MacLeod, R. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Login, I. S.
Right arrow Articles by MacLeod, R. M.

Endocrinology, Vol 116, 622-627, Copyright © 1985 by Endocrine Society

ARTICLES

The effects of maitotoxin on 45Ca2+ flux and hormone release in GH3 rat pituitary cells

IS Login, AM Judd, MJ Cronin, K Koike, G Schettini, T Yasumoto and RM MacLeod

Maitotoxin has been reported to activate calcium channels and stimulate calcium-dependent functions in several tissues, but a thorough investigation of 45Ca2+ fluxes is lacking. To characterize the influence of maitotoxin on 45Ca2+ flux in greater detail, we incubated dispersed GH3 pituitary tumor cells in 45Ca2+ with maitotoxin and other agents affecting calcium channels. Within 10 sec of exposure, maitotoxin induced a net calcium influx in cells at isotopic equilibrium. Calcium uptake was concentration dependent between 0.4 and 40 ng/ml maitotoxin and was inhibited by antagonists of voltage- dependent calcium channels but not by inhibitors of sodium channels. PRL and GH release from perifused GH3 cells was stimulated within 1 min by maitotoxin. We conclude that maitotoxin causes a rapid, concentration-dependent influx of calcium through presumed voltage- dependent endogenous calcium channels, culminating in enhanced hormone release. This potent toxin may provide a more precise understanding of the role of calcium in the stimulus-secretion coupling process.




HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Endocrinology Endocrine Reviews J. Clin. End. & Metab.
Molecular Endocrinology Recent Prog. Horm. Res. All Endocrine Journals
Copyright © 1985 by The Endocrine Society