Biosynthesis and release of thyrotropin-releasing hormone immunoreactivity in rat pancreatic islets in organ culture. Effects of age, glucose, and streptozotocin
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Biosynthesis and release of thyrotropin-releasing hormone immunoreactivity in rat pancreatic islets in organ culture. Effects of age, glucose, and streptozotocin. / Dolva, L O; Welinder, B S; Hanssen, K F; Nielsen, Jens Høiriis.
I: The Journal of Clinical Investigation, Bind 72, Nr. 6, 12.1983, s. 1867-73.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › fagfællebedømt
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T1 - Biosynthesis and release of thyrotropin-releasing hormone immunoreactivity in rat pancreatic islets in organ culture. Effects of age, glucose, and streptozotocin
AU - Dolva, L O
AU - Welinder, B S
AU - Hanssen, K F
AU - Nielsen, Jens Høiriis
PY - 1983/12
Y1 - 1983/12
N2 - Thyrotropin-releasing hormone immunoreactivity (TRH-IR) was measured in isolated islets and in medium from rat pancreatic islets maintained in organ culture. TRH-IR in methanol extracts of both islets and culture medium was eluted in the same position as synthetic TRH by ion-exchange and gel chromatography and exhibited dilution curves parallel with synthetic TRH in radioimmunoassay. [3H]Histidine was incorporated into a component that reacted with TRH antiserum and had the same retention time as synthetic TRH on reversed-phase high-performance liquid chromatography. A continuous release of TRH-IR into the culture medium was observed from islets of both 5-d-old (newborn) and 30-d-old (adult) rats with a maximum on the second day of culture (28.7 +/- 7.0 and 13.3 +/- 3.6 fmol/islet per d, respectively). The content of TRH-IR was higher in freshly isolated islets from newborn rats (22.4 +/- 2.3 fmol/islet) than in adult rat islets, which, however, increased their content from 1.3 +/- 0.5 to 7.0 +/- 0.5 fmol/islet during the first 3 d of culture. Adult rat islets maintained in medium with 20 mM glucose released significantly more TRH-IR than islets in 3.3 mM glucose medium (13.0 +/- 0.7 vs. 4.3 +/- 0.3 fmol/islet per d). In contrast, the content of TRH-IR in the islets was reversed (1.4 +/- 0.3 vs. 4.7 +/- 1.6 fmol/islet). By exposing islets from newborn rats to streptozotocin 0.7 mg/ml for 30 min, a 50% reduction of TRH-IR content in the islets compared with the non-treated islets was seen after subsequent culture for 7 d. The insulin content was reduced by 80%, while glucagon was slightly elevated. In conclusion, these results indicate that TRH is synthesized in rat pancreatic islets, and that the release is stimulated by glucose.
AB - Thyrotropin-releasing hormone immunoreactivity (TRH-IR) was measured in isolated islets and in medium from rat pancreatic islets maintained in organ culture. TRH-IR in methanol extracts of both islets and culture medium was eluted in the same position as synthetic TRH by ion-exchange and gel chromatography and exhibited dilution curves parallel with synthetic TRH in radioimmunoassay. [3H]Histidine was incorporated into a component that reacted with TRH antiserum and had the same retention time as synthetic TRH on reversed-phase high-performance liquid chromatography. A continuous release of TRH-IR into the culture medium was observed from islets of both 5-d-old (newborn) and 30-d-old (adult) rats with a maximum on the second day of culture (28.7 +/- 7.0 and 13.3 +/- 3.6 fmol/islet per d, respectively). The content of TRH-IR was higher in freshly isolated islets from newborn rats (22.4 +/- 2.3 fmol/islet) than in adult rat islets, which, however, increased their content from 1.3 +/- 0.5 to 7.0 +/- 0.5 fmol/islet during the first 3 d of culture. Adult rat islets maintained in medium with 20 mM glucose released significantly more TRH-IR than islets in 3.3 mM glucose medium (13.0 +/- 0.7 vs. 4.3 +/- 0.3 fmol/islet per d). In contrast, the content of TRH-IR in the islets was reversed (1.4 +/- 0.3 vs. 4.7 +/- 1.6 fmol/islet). By exposing islets from newborn rats to streptozotocin 0.7 mg/ml for 30 min, a 50% reduction of TRH-IR content in the islets compared with the non-treated islets was seen after subsequent culture for 7 d. The insulin content was reduced by 80%, while glucagon was slightly elevated. In conclusion, these results indicate that TRH is synthesized in rat pancreatic islets, and that the release is stimulated by glucose.
KW - Aging
KW - Animals
KW - Animals, Newborn
KW - Chromatography, High Pressure Liquid
KW - Culture Media
KW - Depression, Chemical
KW - Dose-Response Relationship, Drug
KW - Female
KW - Glucagon
KW - Glucose
KW - Insulin
KW - Islets of Langerhans
KW - Male
KW - Organ Culture Techniques
KW - Rats
KW - Rats, Inbred Strains
KW - Streptozocin
KW - Thyrotropin-Releasing Hormone
U2 - 10.1172/JCI111149
DO - 10.1172/JCI111149
M3 - Journal article
C2 - 6227632
VL - 72
SP - 1867
EP - 1873
JO - Journal of Clinical Investigation
JF - Journal of Clinical Investigation
SN - 0021-9738
IS - 6
ER -
ID: 47975265