Author/Editor		Rituper, Boštjan
Title		Elektrofiziološke meritve fuzije posameznega mešička s plazmalemo v primarni kulturi podganjih laktotrofov
Type		monografija
Place		Ljubljana
Publisher		Univerza v Ljubljani, Medicinska fakulteta
Publication year		2005
Volume		str. 32
Language		slo
Abstract		BACKGROUND. Hyperprolactinemia, increased plasma concentration of prolactin, is accompanied with symptoms such as impotence, amenorrhea and galactorrhea. It can be caused by pituitary tumors (usually adenomas), antipsychotic therapy and stress, which acts on prolactin secreting lactotrophs indirectly via neuronal system. However, in lower vertebrates lactotrophs may respond directly to stress. Whether such direct responsiveness to stress stimuli exists in mammalian cells, has not yet been studied in detail. Anvt. The aim of our research was to determine whether mammalian pituitary cells can directly respond to osmotic changes in their environment by changing their secretory activity. For that we measured the incidence of elementary events of fusion of secretory vesicles with the plasma membrane at normal and hypoosmotic extracellular conditions. HYPOTHESIS. Since prolactin is a hormone that in lower vertebrates participates in osmoregulation, we have compared secretory activity before and after stimulation with hypoosmotic medium to test the following hypothesis: Mammalian lactotrophs respond directly to osmotic stress. METHODS. We have measured the activity of isolated lactotrophs, prepared as primary cultures, by electrophysiological monitoring of changes in membrane capacitance, a parameter related to changes in surface area of cell membrane. The surface area of plasmalemma increases when the membrane of an exocytotic vesicle fuses with the plasma membrane. Detection probability of vesicle fusion with the plasma membrane is very high, if measurements are preformed in a small patch of membrane, since background noise is relatively low is such a recording configuration. (Abstract trunacted at 2000 characters)
Descriptors		EXOCYTOSIS PROLACTIN PITUITARY GLAND OSMOTIC PRESSURE ELECTRIC CONDUCTIVITY RATS PATCH-CLAMP TECHNIQUES CELLS, CULTURED