Osmotic regulation of hypothalamo-neurointermediate lobe corticotrophin-releasing factor-41 in the rat.
We have detected significant amounts of corticotrophin-releasing factor-41 (CRF-41) in the rat hypothalamo-neurointermediate lobe system using a radioimmunoassay and reversed-phase high-performance liquid chromatography. Total amounts of CRF-41 in extracts of median eminence (ME), supraoptic nucleus (SON), paraventricular nucleus (PVN) and neurointermediate lobe (NIL) from control animals were 1076 +/- 132, 196 +/- 44, 22 +/- 7 and 147 +/- 50 fmol respectively (means +/- S.E.M., n = 6). In animals given 340 mmol NaCl/l instead of tap water to drink for 12 days, no significant changes occurred in the CRF-41 content of the ME, SON or PVN, but CRF-41 content increased more than twofold in the NIL (362 +/- 58 fmol). Plasma concentrations of CRF-41 and ACTH in control animals were 23 +/- 6 and 51 +/- 8 pmol/l respectively. After saline treatment no significant change in plasma CRF-41 was detected (20 +/- 8 pmol/l) but concentrations of circulating ACTH were decreased (15 +/- 2 pmol/l). The CRF-41 content of both the ME and the NIL was significantly depleted after intracerebroventricular injection of colchicine (414 +/- 81 and 34 +/- 7 fmol respectively). These data suggest that NIL CRF-41 is of hypothalamic origin and can be regulated by an osmotic stimulus.
Jessop
D S
DS
Medical Unit, Charing Cross and Westminster Medical School, Westminster Hospital, London.
Eckland
D J
DJ
Todd
K
K
Lightman
S L
SL
D000324:Adrenocorticotropic Hormone / Q000097:blood; D000818:Animals; D003078:Colchicine / Q000494:pharmacology; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism*; D007031:Hypothalamus / Q000187:drug effects / Q000502:physiology*; D008297:Male; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012982:Sodium, Dietary / Q000008:administration & dosage; D014882:Water-Electrolyte Balance
D012982:Sodium, Dietary; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D003078:Colchicine