Distribution and concentration of urocortin, and effect of adrenalectomy on its content in rat hypothalamus.
We developed a specific and sensitive radioimmunoassay (RIA) for rat urocortin (rUcn) and investigated the tissue distribution and concentration of immunoreactive (IR-)Ucn in rats. Antiserum was obtained by immunizing rabbits with synthetic rUcn21-35 coupled with bovine thyroglobulin. 125I-[Tyr]18-rUcn19-37 was used as the tracer. The RIA detected synthetic rUcn1-40 as low as 0.4 fmol/tube, and did not cross-react with other corticotropin-releasing factor-related peptides. IR-Ucn was widely distributed in central nervous system, endocrine organs, and digestive system. Its concentration was highest in pituitary (11.0 +/- 1.36 pmol/g.w.w., mean +/- SEM, n=4). Reverse-phase HPLC revealed that hypothalamic IR-Ucn had similar chromatographic mobility to synthetic rUcn1-40. However, bilateral adrenalectomy did not influence the hypothalamic IR-Ucn content. Our results suggest that Ucn may play important roles in various tissues in normal rats, but not behave as a hypothalamic hypophysiotropic factor in mediating adrenocorticotropin secretion in adrenalectomized rats.
Oki
Y
Y
Department of Medicine, Hamamatsu University School of Medicine, Japan. okitaka@hama-med.ac.jp
Iwabuchi
M
M
Masuzawa
M
M
Watanabe
F
F
Ozawa
M
M
Iino
K
K
Tominaga
T
T
Yoshimi
T
T
D000311:Adrenal Glands / Q000502:physiology* / Q000601:surgery; D000315:Adrenalectomy; D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003346:Corticotropin-Releasing Hormone / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D007031:Hypothalamus / Q000378:metabolism*; D007106:Immune Sera; D008297:Male; D008969:Molecular Sequence Data; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D054832:Urocortins
D007106:Immune Sera; D054832:Urocortins; D003346:Corticotropin-Releasing Hormone