Effect of hypertonic saline on the corticotropin-releasing hormone and arginine vasopressin content of the rat pituitary neurointermediate lobe.
The changes in the levels of corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) in the neurointermediate lobe of the pituitary (NIL) following hypertonic saline administration were examined in rats. The plasma osmotic pressure in rats receiving 2% NaCl for 8 days was greatly increased. Plasma AVP concentration in rats receiving 2% NaCl for 8 days were significantly higher than in control rats (566% of the control level). Plasma corticosterone was significantly higher in the saline-treated rats than in controls, whereas plasma ACTH was not significantly different. The pituitary ACTH concentration was much higher in the saline-treated rats than in controls. CRH in the NIL was increased significantly by saline treatment (419% of the control concentration), whereas the CRH in the paraventricular nucleus and median eminence of control and saline-treated rats did not differ significantly. The AVP in the NIL fell greatly in saline treated rats. The extract from both control and saline-treated rats showed a major peak for immunoreactive CRH, with a retention time identical to that of rat CRH. However, the peak was much higher in the extract from saline-treated rats. The immunoreactive AVP peak was greatly reduced in saline-treated rats. These results suggest that hypertonic saline administration increases the CRH in the NIL and causes AVP hypersecretion and/or hyperfunction of magnocellular-NIL CRH might be responsible for pituitary-adrenal stimulation in saline-treated rats.
Hashimoto
K
K
Third Department of Internal Medicine, Okayama University Medical School, Japan.
Suemaru
S
S
Hirasawa
R
R
Takao
T
T
Makino
S
S
Kageyama
J
J
Ogasa
T
T
Ota
Z
Z
Kawata
M
M
D000305:Adrenal Cortex Hormones / Q000097:blood; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism*; D001835:Body Weight / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism*; D008297:Male; D008473:Median Eminence / Q000378:metabolism; D009997:Osmotic Pressure / Q000187:drug effects; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism; D010904:Pituitary Gland, Posterior / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*
D000305:Adrenal Cortex Hormones; D012462:Saline Solution, Hypertonic; D001127:Arginine Vasopressin; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone