Biomaterial Database

Prostaglandin E2-induced luteinizing hormone-releasing hormone release involves mobilization of intracellular Ca+2. 1985

S R Ojeda, and A Negro-Vilar

The present in vitro experiments were performed to examine the involvement of Ca+2 in the mechanism by which prostaglandin E2 (PGE2) induces LHRH release from the median eminence (ME) of the hypothalamus. Stepwise decreases in the Ca+2 concentration of the incubation medium reduced the LHRH response to PGE2. Nevertheless, neither complete omission of Ca+2 (residual Ca+2 concentration, 3.5 microM) nor chelation of residual Ca+2 with EGTA prevented the stimulatory effect of the PG, suggesting that a significant portion of the PGE2 effect on LHRH release is independent of extracellular Ca+2. Blockade of Ca+2 influx with verapamil, a Ca+2 entry blocker, demonstrated that this component of the PGE2 effect is completely independent of inward Ca+2 movement. Depletion of intraterminal Ca+2 stores by exposure of the MEs to the Ca+2 ionophore A23187 in medium without Ca+2 containing EGTA almost completely obliterated the subsequent LHRH response to PGE2, indicating that normal intraterminal Ca+2 levels are important for the PGE2 effect to occur. Preloading the ME terminals with 45Ca+2 and subsequent stimulation with PGE2 demonstrated that even in the absence of extracellular Ca+2, PGE2 stimulates Ca+2 efflux from the terminals, and this Ca+2 movement occurs temporarily associated with LHRH release. Depolarization of ME terminals with 56 mM K+ in the presence of normal Ca+2 concentration resulted in massive efflux of 45Ca+2 and a greater LHRH response than that produced by PGE2, suggesting that the effect of PGE2 is not the consequence of a nonspecific general depolarization of ME nerve terminals. Thus, although a full LHRH response to (exogenous) PGE2 necessitates normal extraterminal Ca+2 concentrations, the results indicate that translocation of Ca+2 from intracellular stores is an event involved in the mechanism by which PGE2 releases LHRH.

UI	MeSH Term	Description	Entries
D007987	Gonadotropin-Releasing Hormone	A decapeptide that stimulates the synthesis and secretion of both pituitary gonadotropins, LUTEINIZING HORMONE and FOLLICLE STIMULATING HORMONE. GnRH is produced by neurons in the septum PREOPTIC AREA of the HYPOTHALAMUS and released into the pituitary portal blood, leading to stimulation of GONADOTROPHS in the ANTERIOR PITUITARY GLAND.	FSH-Releasing Hormone,GnRH,Gonadoliberin,Gonadorelin,LH-FSH Releasing Hormone,LHRH,Luliberin,Luteinizing Hormone-Releasing Hormone,Cystorelin,Dirigestran,Factrel,Gn-RH,Gonadorelin Acetate,Gonadorelin Hydrochloride,Kryptocur,LFRH,LH-RH,LH-Releasing Hormone,LHFSH Releasing Hormone,LHFSHRH,FSH Releasing Hormone,Gonadotropin Releasing Hormone,LH FSH Releasing Hormone,LH Releasing Hormone,Luteinizing Hormone Releasing Hormone,Releasing Hormone, LHFSH
D008297	Male		Males
D008473	Median Eminence	Raised area at the infundibular region of the HYPOTHALAMUS at the floor of the BRAIN, ventral to the THIRD VENTRICLE and adjacent to the ARCUATE NUCLEUS OF HYPOTHALAMUS. It contains the terminals of hypothalamic neurons and the capillary network of hypophyseal portal system, thus serving as a neuroendocrine link between the brain and the PITUITARY GLAND.	Eminentia Mediana,Medial Eminence,Eminence, Medial,Eminence, Median,Eminences, Medial,Eminentia Medianas,Medial Eminences,Mediana, Eminentia,Medianas, Eminentia
D011458	Prostaglandins E	(11 alpha,13E,15S)-11,15-Dihydroxy-9-oxoprost-13-en-1-oic acid (PGE(1)); (5Z,11 alpha,13E,15S)-11,15-dihydroxy-9-oxoprosta-5,13-dien-1-oic acid (PGE(2)); and (5Z,11 alpha,13E,15S,17Z)-11,15-dihydroxy-9-oxoprosta-5,13,17-trien-1-oic acid (PGE(3)). Three of the six naturally occurring prostaglandins. They are considered primary in that no one is derived from another in living organisms. Originally isolated from sheep seminal fluid and vesicles, they are found in many organs and tissues and play a major role in mediating various physiological activities.	PGE
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
D000242	Cyclic AMP	An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.	Adenosine Cyclic 3',5'-Monophosphate,Adenosine Cyclic 3,5 Monophosphate,Adenosine Cyclic Monophosphate,Adenosine Cyclic-3',5'-Monophosphate,Cyclic AMP, (R)-Isomer,Cyclic AMP, Disodium Salt,Cyclic AMP, Monoammonium Salt,Cyclic AMP, Monopotassium Salt,Cyclic AMP, Monosodium Salt,Cyclic AMP, Sodium Salt,3',5'-Monophosphate, Adenosine Cyclic,AMP, Cyclic,Adenosine Cyclic 3',5' Monophosphate,Cyclic 3',5'-Monophosphate, Adenosine,Cyclic Monophosphate, Adenosine,Cyclic-3',5'-Monophosphate, Adenosine,Monophosphate, Adenosine Cyclic
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
D015232	Dinoprostone	The most common and most biologically active of the mammalian prostaglandins. It exhibits most biological activities characteristic of prostaglandins and has been used extensively as an oxytocic agent. The compound also displays a protective effect on the intestinal mucosa.	PGE2,PGE2alpha,Prostaglandin E2,Prostaglandin E2alpha,PGE2 alpha,Prepidil Gel,Prostaglandin E2 alpha,Prostenon,E2 alpha, Prostaglandin,E2, Prostaglandin,E2alpha, Prostaglandin,Gel, Prepidil,alpha, PGE2,alpha, Prostaglandin E2
D051381	Rats	The common name for the genus Rattus.	Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus
D066298	In Vitro Techniques	Methods to study reactions or processes taking place in an artificial environment outside the living organism.	In Vitro Test,In Vitro Testing,In Vitro Tests,In Vitro as Topic,In Vitro,In Vitro Technique,In Vitro Testings,Technique, In Vitro,Techniques, In Vitro,Test, In Vitro,Testing, In Vitro,Testings, In Vitro,Tests, In Vitro,Vitro Testing, In