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There have been no detailed in-vitro studies of PRL secretion by human macroprolactinoma cells exposed to bromocriptine (BC) to within a few days of surgical removal. We have studied cells from four such tumours (serum PRL 7.05-247 U/l) and six untreated tumours (serum PRL 4-80.35 U/l) using a
The extracellular ion milieu determines the exocytosis mechanism that is coupled to spontaneous electrical activity. The K(+) ion plays crucial role in this mechanism: as the potassium current is associated with membrane hyperpolarization and hormone release through protein cascade activation. The
Human prolactinoma cells were maintained in culture for a period of at least 8 days and were able to secrete PRL in large amounts. This secretion was inhibited by bromocriptine, an agonist of dopaminergic receptors, in a dose-dependent manner. The cells showed electrical activity (action potentials)
The oral non-ergot D2-dopamine agonist quinagolide (CV 205-502, CAS 87056-78-8) has proven to be highly effective in suppressing elevated prolactin (PRL) levels. It was the aim of this study to search for possible interference of the drug with other endocrine systems which are partly under
The activity of T4 5'-monodeiodinase (5'D) in the pituitary was measured in 12 patients with pituitary adenoma (3 patients with acromegaly, 2 with prolactinoma, 1 with Cushing's disease, 1 with TSH-producing tumor, and 5 with nonfunctioning tumor) and, as a control, in a patient who died of parotid
Dopamine receptors of D2 type present on lactotroph cells are coupled to a large series of transduction mechanisms. Beside their negative coupling with adenylate cyclase, they are also coupled with potassium and calcium channels, leading to a decreased intracellular calcium concentration. In
Dopamine receptors of D2 type present on lactotroph cells are coupled to a large series of transduction mechanisms. Beside their negative coupling with adenylate cyclase, they are also coupled with potassium and calcium channels, leading to a decreased intracellular calcium concentration. In
Previous in vitro studies have demonstrated zinc (Zn++) inhibition of basal and of potassium (K+) or thyrotropin-releasing hormone (TRH)-stimulated prolactin (PRL) secretion, in a selective, reversible, and dose-dependent manner. Thus, Zn++ may regulate physiologically pituitary PRL secretion.
Prolactin is known to have renal sodium retention properties in animals. In man, only two studies have suggested a similar effect in healthy volunteers or in patients with microprolactinoma. Since hyperprolactinemia is frequently observed in liver disease, this prospective study of 19 patients