In vivo and in vitro effects of angiotensin II on the release of beta-endorphin-like immunoreactivity.
The effect of angiotensin II (A II) on the release of beta-endorphin-like immunoreactivity (beta-END-LI) in rats was studied in vivo and in vitro. Intravenous injection of 1 microgram/100 g body weight of A II resulted in significant increase in the plasma beta-END-LI level after 10 and 20 min. Intraventricular injection of 1 ng/100 g body weight of A II also resulted in significant increase in the plasma beta-END-LI level after 10 min. A II at concentrations of 10(-12) M-10(-10) caused dose-dependent stimulation of beta-END-LI release from dispersed cells of rat anterior pituitary. On gel chromatography, the beta-END-LI released by incubation of the cells with 10(-10) M A II separated into two components which eluted in the same positions as human beta-lipotropin and human beta-endorphin, respectively. The ratio of beta-LPH to beta-END in these fractions was 5:1 on a molar basis. A II did not stimulate beta-END-LI release in Ca++-free-medium. [Sar1, Ala8]-A II at concentrations of 10(-9) M - 10(-7) M did not stimulate beta-END-LI release from the cells. Addition of [Sar1, Ala8]-A II to the incubation medium inhibited A II-induced beta-END-LI release from the cells. These results indicate that A II acts, at least in part, directly on anterior pituitary cells to stimulate beta-END-LI release and that calcium ion is involved in the mechanism of this effect.
Matsumura
M
M
Inoue
S
S
Yamanoi
A
A
Chikamori
K
K
Saito
S
S
D000804:Angiotensin II / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002850:Chromatography, Gel; D003035:Cobalt / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004723:Endorphins / Q000378:metabolism*; D066298:In Vitro Techniques; D007276:Injections, Intraventricular; D008297:Male; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012504:Saralasin / Q000494:pharmacology; D013997:Time Factors; D001615:beta-Endorphin
D004723:Endorphins; D000804:Angiotensin II; D003035:Cobalt; D001615:beta-Endorphin; D012504:Saralasin; D002118:Calcium