Biomaterial Database

Rat Prl and TSH secretion are regulated differently by K(+)-channel blockers. 1994

X Wang, and T Inukai, and M A Greer, and S E Greer

Department of Medicine, Oregon Health Sciences University, Portland 97201.

All four different K(+)-channel blockers [tetraethylammonium (TEA), a nonselective K(+)-channel blocker; tolbutamide, an ATP-sensitive K(+)-channel blocker; quinine and 4-aminopyridine, both primarily voltage-dependent K(+)-channel blockers] stimulated prolactin (Prl) secretion by acutely dispersed anterior pituitary cells but had no effect on thyroid-stimulating hormone (TSH) secretion. TEA stimulated Prl secretion in a dose-dependent manner between 1 microM and 20 mM, but even as high as 20 mM, TEA did not induce TSH secretion. Valinomycin (2 microM), a K+ ionophore, inhibited both basal and TEA-induced Prl secretion. TEA-stimulated Prl secretion was abolished by using a Ca(2+)-depleted medium or adding 10 microM dopamine. TEA did not reverse the inhibitory effect of dopamine on thyrotropin-releasing hormone-induced Prl secretion. Our data indicate that K+ channels may play a role in the secretion of adenohypophysial hormones that is idiosyncratic for each hormone. Differences in the role of K+ channels may reflect differences between the various pituitary cell types in plasma membrane ion channel composition, membrane potential, or the mechanism of exocytosis.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D011388	Prolactin	A lactogenic hormone secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). It is a polypeptide of approximately 23 kD. Besides its major action on lactation, in some species prolactin exerts effects on reproduction, maternal behavior, fat metabolism, immunomodulation and osmoregulation. Prolactin receptors are present in the mammary gland, hypothalamus, liver, ovary, testis, and prostate.	Lactogenic Hormone, Pituitary,Mammotropic Hormone, Pituitary,Mammotropin,PRL (Prolactin),Hormone, Pituitary Lactogenic,Hormone, Pituitary Mammotropic,Pituitary Lactogenic Hormone,Pituitary Mammotropic Hormone
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D003470	Culture Media	Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.	Media, Culture
D004298	Dopamine	One of the catecholamine NEUROTRANSMITTERS in the brain. It is derived from TYROSINE and is the precursor to NOREPINEPHRINE and EPINEPHRINE. Dopamine is a major transmitter in the extrapyramidal system of the brain, and important in regulating movement. A family of receptors (RECEPTORS, DOPAMINE) mediate its action.	Hydroxytyramine,3,4-Dihydroxyphenethylamine,4-(2-Aminoethyl)-1,2-benzenediol,Dopamine Hydrochloride,Intropin,3,4 Dihydroxyphenethylamine,Hydrochloride, Dopamine
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013757	Tetraethylammonium Compounds	Quaternary ammonium compounds that consist of an ammonium cation where the central nitrogen atom is bonded to four ethyl groups.	Tetramon,Tetrylammonium,Compounds, Tetraethylammonium
D013972	Thyrotropin	A glycoprotein hormone secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Thyrotropin stimulates THYROID GLAND by increasing the iodide transport, synthesis and release of thyroid hormones (THYROXINE and TRIIODOTHYRONINE). Thyrotropin consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the pituitary glycoprotein hormones (TSH; LUTEINIZING HORMONE and FSH), but the beta subunit is unique and confers its biological specificity.	Thyroid-Stimulating Hormone,TSH (Thyroid Stimulating Hormone),Thyreotropin,Thyrotrophin,Hormone, Thyroid-Stimulating,Thyroid Stimulating Hormone
D014634	Valinomycin	A cyclododecadepsipeptide ionophore antibiotic produced by Streptomyces fulvissimus and related to the enniatins. It is composed of 3 moles each of L-valine, D-alpha-hydroxyisovaleric acid, D-valine, and L-lactic acid linked alternately to form a 36-membered ring. (From Merck Index, 11th ed) Valinomycin is a potassium selective ionophore and is commonly used as a tool in biochemical studies.
D015221	Potassium Channels	Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.	Ion Channels, Potassium,Ion Channel, Potassium,Potassium Channel,Potassium Ion Channels,Channel, Potassium,Channel, Potassium Ion,Channels, Potassium,Channels, Potassium Ion,Potassium Ion Channel