TY - JOUR
T1 - Oral administration of theophylline to modify pressor responsiveness to angiotensin II in women with pregnancy-induced hypertension
AU - Everett, Royice B.
AU - Worley, Richard J.
AU - MacDonald, Paul C.
AU - Gant, Norman F.
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 1978/10/15
Y1 - 1978/10/15
N2 - Normally, women become refractory to the pressor effects of infused angiotensin-II (A-II) early in pregnancy. Gravid women destined to develop pregnancy-induced hypertension (PIH) lose this refractoriness to A-II several weeks prior to the detection of hypertension. Normal pregnant women also lose their A-II refractoriness after treatment with prostaglandin synthetase inhibitors and, in this regard, become similar to gravid women who are destined to develop PIH. From this observation, we have concluded that a prostaglandin(s) or a prostaglandin-related substance(s) is likely involved in the mediation of vascular reactivity to A-II during pregnancy. The present study was conducted to ascertain if control of vascular reactivity during pregnancy also involves the cyclic nucleotides. Since theophylline is known to inhibit the action of phosphodiesterase, an action that results in increased cellular levels of cyclic 3′,5′-adenosine monophosphate (cAMP), we evaluated the effective pressor dose of A-II before and after the administration of theophylline to women with mild PIH who were beyond the 28th week of gestation. The effective pressor dose of A-II in these women with PIH before theophylline treatment was 7.3 ± 1.4 ng. × kg.-1 × min.-1 (mean and standard error). Following treatment of these women with the equivalent of 500 mg. of theophylline daily for four days, the effective pressor dose of A-II was 16.7 ± 3.8 ng. × kg.-1 × min.-1 (p < 0.025. These findings are consistent with the view that a prostaglandin(s) synthesized in the arteriole may modulate the vascular refractoriness to A-II by altering the intracellular level of cAMP in vascular tissues.
AB - Normally, women become refractory to the pressor effects of infused angiotensin-II (A-II) early in pregnancy. Gravid women destined to develop pregnancy-induced hypertension (PIH) lose this refractoriness to A-II several weeks prior to the detection of hypertension. Normal pregnant women also lose their A-II refractoriness after treatment with prostaglandin synthetase inhibitors and, in this regard, become similar to gravid women who are destined to develop PIH. From this observation, we have concluded that a prostaglandin(s) or a prostaglandin-related substance(s) is likely involved in the mediation of vascular reactivity to A-II during pregnancy. The present study was conducted to ascertain if control of vascular reactivity during pregnancy also involves the cyclic nucleotides. Since theophylline is known to inhibit the action of phosphodiesterase, an action that results in increased cellular levels of cyclic 3′,5′-adenosine monophosphate (cAMP), we evaluated the effective pressor dose of A-II before and after the administration of theophylline to women with mild PIH who were beyond the 28th week of gestation. The effective pressor dose of A-II in these women with PIH before theophylline treatment was 7.3 ± 1.4 ng. × kg.-1 × min.-1 (mean and standard error). Following treatment of these women with the equivalent of 500 mg. of theophylline daily for four days, the effective pressor dose of A-II was 16.7 ± 3.8 ng. × kg.-1 × min.-1 (p < 0.025. These findings are consistent with the view that a prostaglandin(s) synthesized in the arteriole may modulate the vascular refractoriness to A-II by altering the intracellular level of cAMP in vascular tissues.
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U2 - 10.1016/0002-9378(78)90767-6
DO - 10.1016/0002-9378(78)90767-6
M3 - Article
C2 - 212952
AN - SCOPUS:0018142805
SN - 0002-9378
VL - 132
SP - 359
EP - 362
JO - American journal of obstetrics and gynecology
JF - American journal of obstetrics and gynecology
IS - 4
ER -