Journal ArticleDOI
Superfusion of Rat Anterior Pituitary Cells Attached to Cytodex Beads: Validation of a Technique
Mark A. Smith,Wylie Vale +1 more
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TLDR
The cocarcinogen phorbol myristate acetate (12-O-tetradecanoyl-phorbol-13-acetate) induced secretion of all pituitary hormones and continued to do so for hours after a short pulse.Abstract:
A superfusion method consisting of fully recovered, dissociated pituitary cells adhering to Cytodex beads has proved useful in monitoring the dynamics of hormone secretion over time. Male rat anterior pituitaries were dissociated with collagenase and Viokase, then cultured in the presence of Cytodex beads for 3-5 days, during which time the cells attached firmly to the surface of the beads. The bead-attached cells were stable and could be transferred to any vessel without the need for centrifugation or further trypsinization. For this application, the bead-attached cells were packed in a column and superfused with a low bicarbonate buffer requiring no CO2 gassing. Viability was more than 95% after 48 h in the column. The cells responded in a normal physiological manner to hypothalamic releasing and inhibitory peptides. The ED50 was 0.3 nM for somatostatin and 1.2 nM for gonadotropin-releasing hormone. A postinhibitory rebound of GH secretion was observed after the discontinuation of large doses of somatostatin. LH secretion reached maximal levels within 6 min after 10 nM gonadotropin-releasing hormone, but started declining after 2 h of continuous stimulation and dropped close to baseline within 18 h. GH release was significantly increased by prostaglandin E2, 3-isobutyl-1-methylxanthine, and 8-bromo-cAMP. LH secretion increased 5-fold in response to 1 mM 8-bromo-cAMP, but showed little increase during prostaglandin E2 or 3-isobutyl-1-methylxanthine stimulation. The cocarcinogen phorbol myristate acetate (12-O-tetradecanoyl-phorbol-13-acetate) induced secretion of all pituitary hormones and continued to do so for hours after a short pulse. The superfusion system is simple to operate and has proven effective in studying transient phenomena, desensitization, and short term kinetics of secretagogues.read more
Citations
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Journal ArticleDOI
Neuroendrocrine regulation of prolactin release
TL;DR: In this paper, a synthese sur la regulation neuroendocrinienne de la liberation de la prolactine is presented, along with facteurs de liberation de the prolactines.
Journal ArticleDOI
Independent effects of growth hormone releasing factor on growth hormone release and gene transcription
Marcia Barinaga,Marcia Barinaga,Marcia Barinaga,Louise M. Bilezikjian,Wylie Vale,Michael G. Rosenfeld,Ronald M. Evans +6 more
TL;DR: It is demonstrated here that GHRF stimulates GH gene transcription independently of GH release and, conversely, that other agents can stimulate GH release without affecting transcription of the GH gene.
Journal ArticleDOI
Hormone-induced redistribution of calcium-activated phospholipid-dependent protein kinase in pituitary gonadotrophs.
TL;DR: Findings suggest that hormonal activation of protein kinase C is an intermediate step in the stimulation of pituitary LH secretion by GnRH, and the ability of GnRH to cause rapid translocation of cytosolic protein Kinase C to a membrane-associated form is suggested.
Journal ArticleDOI
Mechanism of action of gonadotropin-releasing hormone. Involvement of phospholipid turnover in luteinizing hormone release.
TL;DR: It is demonstrated that GnRH increases arachidonic acid formation from the phospholipids of pituitary gonadotrophs, and indicates that the fatty acid or its metabolites can initiate LH release.
Journal ArticleDOI
Desensitization to gonadotropin-releasing hormone observed in superfused pituitary cells on Cytodex beads.
Mark A. Smith,Wylie Vale +1 more
TL;DR: Results demonstrate that continuous, but not intermittent, exposure to GnRH is capable of producing desensitization in superfused anterior pituitary cells.
References
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Journal ArticleDOI
Hypophysial responses to continuous and intermittent delivery of hypopthalamic gonadotropin-releasing hormone
TL;DR: The initiation of continuous GnRH administration in animals with lesions and in which gonadotropin secretion is reestablished by intermittent GnRH replacement can result in a "desensitization" or "down regulation" of the processes responsible for gonadotropic hormone release.
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Journal ArticleDOI
Culture of Enzymatically Dispersed Anterior Pituitary Cells: Functional Validation of a Method
TL;DR: The sensitivity of the cultured cells to TRF and LRF is maintained for more than 2 weeks in culture although the magnitude of the secretory response and the intracellular hormone content declines with time in culture.
Journal ArticleDOI
Hormonal regulation of peptide receptors and target cell responses
TL;DR: Receptor number is determined by hormone-induced changes in membrane conformation, irreversible ligand binding, and processing of ligand–receptor complexes during hormone action.
Journal ArticleDOI
Action of growth-hormone-release inhibitory hormone in healthy men and in acromegaly
R. Hall,Andrew V. Schally,D.C. Evered,Abba J. Kastin,C. H. Mortimer,W. M. G. Tunbridge,G. M. Besser,David H. Coy,D.J Goldie,McNeilly As,C Phenekos,D Weightman +11 more
TL;DR: The synthetic growth-hormone-release inhibitory hormone inhibits G.R.R.-I.H. response to insulin-induced hypoglycaemia without affecting the prolactin or corticosteroid responses, but the effects are short-lived.
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Desensitization to gonadotropin-releasing hormone observed in superfused pituitary cells on Cytodex beads.
Mark A. Smith,Wylie Vale +1 more