Sb. Guild et G. Cramb, Characterisation of the effects of natriuretic peptides upon ACTH secretion from the mouse pituitary, MOL C ENDOC, 152(1-2), 1999, pp. 11-19
The involvement of natriuretic peptides in the regulation of ACTH secretion
in mice hemi-pituitary preparations was investigated. Atrial natriuretic p
eptide (ANP), brain natriuretic peptide (BNP) and C-type natriuretic peptid
e (CNP) all inhibited CRF (10(-9) M)-evoked ACTH secretion over a concentra
tion range of 10(-12)-10(-10) M and also stimulated cyclic GMP accumulation
over a concentration range of 10(-8)-10(-5) M. CNP was the most effective
both in the inhibition of ACTH secretion and in the stimulation of cyclic G
MP accumulation. Coincubation of hemi-pituitaries with 8bromo-cyclic GMP (1
0(-4) M) completely inhibited CRF (10(-9) M)-evoked ACTH secretion. Norther
n blot analysis revealed that all three major isoforms of the natriuretic p
eptide receptors are expressed in the mouse pituitary. These results demons
trate that natriuretic peptides do inhibit CRF-stimulated ACTH secretion fr
om mouse pituitary preparations. A role for cGMP in mediating this effect o
n hormone secretion is indicated but the discrepancy between the efficacies
of natriuretic peptides in inhibiting the secretory response and stimulati
ng cyclic GMP accumulation suggest a more complicated stimulus-secretion co
upling pathway is in operation. (C) 1999 Elsevier Science Ireland Ltd. All
rights reserved.