title: Measurement of somatostatin release in rat brain by microdialysis.
abstract: We determined the most suitable conditions for measuring the somatostatin (SRIF) level by brain microdialysis and investigated its release from the hypothalamus. The relative recovery rate of SRIF was 8.4 +/- 0.5% (mean +/- SE) using a polycarbonate (PC) membrane with the push-pull method at a flow rate of 2 microliters/min. Using tubes with an internal diameter of 0.28 mm and lengths of 5, 25, 50 and 100 cm, the relative recovery rates using a PC membrane with the push method were 8.2 +/- 0.5%, 7.3 +/- 0.6%, 6.2 +/- 0.5% and 4.1 +/- 0.6%, respectively. When using tubes with an internal diameter of 0.1 mm and lengths of 5, 25, 50 and 100 cm, the relative recovery rates were 7.3 +/- 0.7%, 5.6 +/- 1.0%, 3.5 +/- 1.1% and 1.4 +/- 0.7%, respectively. The relative recovery rate was 5.2 +/- 0.5% with a polysulfone (PS-F, Fresenius) membrane, 4.5 +/- 0.4% with a PS-H (Hospal) membrane, 2.6 +/- 0.2% with an ethylenevinyl alcohol membrane (EVAL), 5.1 +/- 0.8% with a polyvinyl alcohol (PVA) membrane and 10.4 +/- 0.8% with a PS-K (Kaneka) membrane. With the push method, the extracellular SRIF level in rat pituitary was 42.8 +/- 1.8 pg/ml with a PC membrane, 23.1 +/- 2.9 pg/ml with an EVAL membrane at a flow rate of 2 microliters/min. With the push-pull method, it was 52.7 +/- 5.2 pg/ml using a PC membrane, 33.5 +/- 2.8 pg/ml using a PVA membrane and 54.4 +/- 3.2 pg/ml using a PS-K membrane.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: First Department of Internal Medicine, School of Medicine, University of Tokushima, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Takahashi
authors.forename: Y
authors.initials: Y
authors.lastname: Shintani
authors.forename: T
authors.initials: T
authors.lastname: Okauchi
authors.forename: M
authors.initials: M
authors.lastname: Ishikawa
authors.forename: H
authors.initials: H
authors.lastname: Bando
authors.forename: T
authors.initials: T
authors.lastname: Azekawa
authors.forename: Y
authors.initials: Y
authors.lastname: Morita
authors.forename: S
authors.initials: S
authors.lastname: Saito
mesh_terms: D000777:Anesthetics / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000378:metabolism*; D008297:Male; D008567:Membranes, Artificial; D017551:Microdialysis / Q000295:instrumentation; D010902:Pituitary Gland / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013004:Somatostatin / Q000378:metabolism*; D014462:Ultrafiltration
chemical_list: D000777:Anesthetics; D008567:Membranes, Artificial; D013004:Somatostatin