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001-es BibID:	BIBFORM033900
035-os BibID:	PMID:8251954 WOS:A1993MB41500002
Első szerző:	Halmos Gábor (gyógyszerész, receptorfarmakológus, experimentális onkológus)
Cím:	Use of radioreceptor assay and cell superfusion system for in vitro screening of analogs of growth hormone-releasing hormone / Gabor Halmos, Zoltan Rekasi, Balazs Szoke, Andrew V. Schally
Dátum:	1993
Megjegyzések:	In the search for more active agonists and antagonists of human growth hormone-releasing hormone (hGH-RH), various analogs are being synthesized. In order to follow the binding affinity of these analogs, we have developed a sensitive in vitro radioreceptor assay for GH-RH based on binding of labeled [His1,Nle27]hGH-RH(1-32)NH2 to rat anterior pituitary membrane homogenates by adapting and modifying earlier methods. Scatchard analysis of saturation binding data demonstrated the presence of a single class of specific binding sites for GH-RH in membranes of rat anterior pituitaries with a Bmax of 33.3 +/- 5.2 fmol/mg protein and an apparent Kd of 0.19 +/- 0.02 nM. In displacement analyses, we compared the binding affinity of [His1,Nle27]hGH-RH(1-32)NH2 with its iodinated derivative. No significant differences were detected in IC50 concentrations ranging from 0.97 to 3.4 nM between labeled and nonlabeled hGH-RH analogs. These findings demonstrate the validity of the radioreceptor assay. To evaluate the biological activities of hGH-RH derivatives, we applied a sensitive, dispersed rat pituitary cell superfusion system. This dynamic in vitro system eliminates the drawbacks of the static pituitary cell culture. No differences were observed in biological activities of the iodinated and noniodinated hGH-RH analogs. GH-releasing activity obtained from the superfusion assay correlated well with GH-RH receptor binding affinity for all nonlabeled and labeled hGH-RH analogs examined. These two methods are fast, simple, and relatively inexpensive, and provide quantitative data on receptor affinities, biological activities, and hence structure-affinity and structure-activity relationships. Joint use of these two in vitro systems appears to be suitable for screening newly synthesized GH-RH analogs.
Tárgyszavak:	Orvostudományok Gyógyszerészeti tudományok idegen nyelvű folyóiratközlemény külföldi lapban külföldön készült közlemény
Megjelenés:	Receptor. - 3 : 2 (1993), p. 87-97. -
További szerzők:	Rékási Zoltán Szőke Balázs Schally, Andrew Victor
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM033854
035-os BibID:	PMID:7894336 WOS:A1994QA83500001
Első szerző:	Szende Béla
Cím:	The concentration of LH-RH receptors in the nuclei of pancreatic cancer cells : effect of (D-Trp6)LH-RH on tumor-bearing Syrian golden hamsters / Bela Szende, Andras Csikós, Karoly Szepeshazi, Jimmy D. Neill, Jeff J. Mulchahey, Gabor Halmos, Karoly Lapis, Andrew V. Schally
Dátum:	1994
Megjegyzések:	LH-RH analogs cause some inhibition of growth of pancreatic cancers. Syrian golden hamsters bearing chemically induced pancreatic cancers were treated with [D-Trp6]LH-RH for 3 d before sacrifice. LH-RH receptors were localized by electron-microscopic immunohistochemistry in the tumor cells of both treated and untreated hamsters. [D-Trp6]LH-RH treatment resulted in a marked increase in the concentration of LH-RH receptors in the nuclei. The dissociation constants (Kd) and the maximal binding capacity of the LH-RH receptors (Bmax), measured by radioreceptor assay, were higher in the nuclei of the pancreatic tumor cells of hamsters treated with [D-Trp6]LH-RH than in the untreated controls. Pancreatic cells of tumor-free hamsters did not show immunostaining for LH-RH receptors. A possible correlation between the increase in the concentration of the LH-RH receptors in the nuclei and the tumor growth-inhibiting activity of [D-Trp6]LH-RH is suggested.
Tárgyszavak:	Orvostudományok Gyógyszerészeti tudományok idegen nyelvű folyóiratközlemény külföldi lapban külföldön készült közlemény
Megjelenés:	Receptor. - 4 : 4 (1994), p. 201-207. -
További szerzők:	Csikós András Szepesházi Károly Neill, Jimmy D. Mulchahey, Jeff J. Halmos Gábor (1962-) (gyógyszerész, receptorfarmakológus, experimentális onkológus) Lapis Károly Schally, Andrew Victor
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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