Role of brain kallikrein-kinin system in regulation of adrenocorticotropin release.
We evaluated whether the brain kallikrein-kinin system plays a role in the regulation of adrenocorticotropin (ACTH) release in rats. Intracerebroventricular (icv) injection of bradykinin (0.24 nmol) increased plasma immunoreactive ACTH (irACTH) levels (from 93 +/- 4 to 200 +/- 12 pg/ml, P less than 0.01). This effect was prevented by icv kinin antagonist at 15.4 nmol/h (from 98 +/- 5 to 108 +/- 6 pg/ml; not significant). The antagonist did not alter the increase in plasma irACTH levels induced by icv corticotropin-releasing factor (CRF), arginine vasopressin, or prostaglandin E2. Melittin (7 nmol/h icv) increased plasma irACTH from 95 +/- 4 to 268 +/- 7 pg/ml (P less than 0.01). This effect was prevented by icv kinin antagonist (15.4 nmol/h), kallikrein antibodies (13 pmol/h), or indomethacin (0.28 mmol/h). ACTH response to melittin was not altered by antagonists of CRF or vasopressin. Intra-arterial injection of insulin (0.3 IU/kg body wt) reduced plasma glucose levels to a similar extent in rats given icv kinin antagonist or vehicle; the ACTH response to insulin-induced hypoglycemia was slightly less in rats given kinin antagonist than in those given vehicle (55 +/- 5 vs. 86 +/- 4 pg/ml, P less than 0.05). The brain kallikrein-kinin system may play a role in the regulation of ACTH secretion in stimulated conditions.
Madeddu
P
P
Department of Clinical Medicine, Sassari University, Italy.
Anania
V
V
Alagna
S
S
Troffa
C
C
Parpaglia
P P
PP
Tonolo
G
G
Demontis
M P
MP
Varoni
M V
MV
Fattaccio
C
C
Glorioso
N
N
D000324:Adrenocorticotropic Hormone / Q000097:blood / Q000378:metabolism*; D000595:Amino Acid Sequence; D000704:Analysis of Variance; D000818:Animals; D001127:Arginine Vasopressin / Q000008:administration & dosage / Q000494:pharmacology; D001786:Blood Glucose / Q000378:metabolism; D001920:Bradykinin / Q000008:administration & dosage / Q000494:pharmacology*; D001921:Brain / Q000502:physiology*; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology*; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage / Q000494:pharmacology; D015232:Dinoprostone / Q000008:administration & dosage / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D007276:Injections, Intraventricular; D007328:Insulin / Q000494:pharmacology; D007610:Kallikreins / Q000502:physiology*; D007705:Kinins / Q000502:physiology*; D008555:Melitten / Q000008:administration & dosage / Q000494:pharmacology; D008969:Molecular Sequence Data; D010052:Ovariectomy; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains
D001786:Blood Glucose; D007328:Insulin; D007705:Kinins; D001127:Arginine Vasopressin; D008555:Melitten; D004958:Estradiol; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D007610:Kallikreins; D015232:Dinoprostone; D001920:Bradykinin