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Title: Cardiovascular and endocrine response to hemorrhage after. cap alpha. /sub 1/-blockade in lambs and ewes

Abstract

To evaluate the role of the ..cap alpha../sub 1/-adrenergic system in the response to hemorrhage during development, lambs and adult sheep were chronically catheterized and hemorrhaged after pretreatment with prazosin or vehicle. The adults became markedly more hypotensive after ..cap alpha../sub 1/-blockade and hemorrhage than after vehicle and hemorrhage, whereas the lambs were no more hypotensive when hemorrhaged after prazosin. In the adults and the lambs hemorrhage produced elevations in plasma renin activity and arginine vasopressin measured by radioimmunoassay. However, after prazosin, the adults had a far greater increase in arginine vasopressin levels than after vehicle treatment.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Wake Forest Univ., Winston-Salem, NC
OSTI Identifier:
5434690
Resource Type:
Journal Article
Resource Relation:
Journal Name: Am. J. Physiol.; (United States); Journal Volume: 252:2
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; HEMORRHAGE; PHYSIOLOGY; RENIN; RADIOIMMUNOASSAY; VASOPRESSIN; AGE DEPENDENCE; ANGIOTENSIN; BLOOD PRESSURE; ENDOCRINE GLANDS; ENZYME ACTIVITY; HOMEOSTASIS; SHEEP; ANIMALS; BODY; CARDIOVASCULAR AGENTS; DOMESTIC ANIMALS; DRUGS; ENZYMES; GLANDS; GLOBULINS; HORMONES; HYDROLASES; IMMUNOASSAY; IMMUNOLOGY; ISOTOPE APPLICATIONS; MAMMALS; NONSPECIFIC PEPTIDASES; ORGANIC COMPOUNDS; ORGANS; PATHOLOGICAL CHANGES; PEPTIDE HORMONES; PEPTIDE HYDROLASES; PITUITARY HORMONES; PROTEINS; RADIOASSAY; RADIOIMMUNOLOGY; RUMINANTS; SYMPTOMS; TRACER TECHNIQUES; VASOCONSTRICTORS; VERTEBRATES; 550601* - Medicine- Unsealed Radionuclides in Diagnostics

Citation Formats

Block, S.M., Rose, J.C., Ernest, J.M., Flowe, K., South, S., and Zimmerman, C. Cardiovascular and endocrine response to hemorrhage after. cap alpha. /sub 1/-blockade in lambs and ewes. United States: N. p., 1987. Web.
Block, S.M., Rose, J.C., Ernest, J.M., Flowe, K., South, S., & Zimmerman, C. Cardiovascular and endocrine response to hemorrhage after. cap alpha. /sub 1/-blockade in lambs and ewes. United States.
Block, S.M., Rose, J.C., Ernest, J.M., Flowe, K., South, S., and Zimmerman, C. 1987. "Cardiovascular and endocrine response to hemorrhage after. cap alpha. /sub 1/-blockade in lambs and ewes". United States. doi:.
@article{osti_5434690,
title = {Cardiovascular and endocrine response to hemorrhage after. cap alpha. /sub 1/-blockade in lambs and ewes},
author = {Block, S.M. and Rose, J.C. and Ernest, J.M. and Flowe, K. and South, S. and Zimmerman, C.},
abstractNote = {To evaluate the role of the ..cap alpha../sub 1/-adrenergic system in the response to hemorrhage during development, lambs and adult sheep were chronically catheterized and hemorrhaged after pretreatment with prazosin or vehicle. The adults became markedly more hypotensive after ..cap alpha../sub 1/-blockade and hemorrhage than after vehicle and hemorrhage, whereas the lambs were no more hypotensive when hemorrhaged after prazosin. In the adults and the lambs hemorrhage produced elevations in plasma renin activity and arginine vasopressin measured by radioimmunoassay. However, after prazosin, the adults had a far greater increase in arginine vasopressin levels than after vehicle treatment.},
doi = {},
journal = {Am. J. Physiol.; (United States)},
number = ,
volume = 252:2,
place = {United States},
year = 1987,
month = 2
}
  • The hypothesis that estradiol-17..beta.. may play a role in prostaglandin F/sub 2/..cap alpha.. (PGF/sub 2/..cap alpha..)-induced luteolysis was tested in ewes following selective destruction of ovarian follicles by x-irradiation. The effects of two injections of (1) 7 mg PGF/sub 2/..cap alpha.., (2) 750 ..mu..g estradiol benzoate (E/sub 2/B) and (3) 7 mg PGF/sub 2/..cap alpha.. + 750 ..mu..g E/sub 2/B were compared in sham and x-irradiated ewes. Treatment of sham-irradiated ewes with PGF/sub 2/..cap alpha.. resulted in luteolysis in all 5 treated ewes, as judged by a fall in the plasma progesterone concentration to non-detectable levels (less than 0.2 ng/ml)more » by 54 h after the first injection. In contrast, luteolysis was not observed in 4 of 5 x-irradiated ewes following treatment with PGF/sub 2/..cap alpha.., as indicated by plasma progesterone levels greater than 1.60 ng/ml 96 h after the first injection and corpus luteum weights in excess of 535 mg. Luteolysis was observed in the fifth animal of this group, ewe No. 20, in which plasma progesterone fell to non-detectable levels and a corpus luteum of 203 mg was observed at autopsy. The mean plasma estradiol concentration ranged between 4 and 9 pg/ml in sham-irradiated, PGF/sub 2/..cap alpha..-treated ewes, but fell to non-detectable levels before treatment with PGF/sub 2/..cap alpha.. in all x-irradiated ewes except No. 20 in which levels as high as 11.6 pg/ml were observed. A large luteinized, cystic follicle was observed at autopsy in ewe No. 20. These observations suggest that destruction of ovarian follicles to remove the primary source of estradiol reduced the effectiveness of PGF/sub 2/..cap alpha.. as a luteolytic agent.« less
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  • The authors compared the cardiovascular and hormonal responses to angiotensin converting enzyme inhibition and hemorrhage of 20% of blood volume in chronically instrumented unanesthetized newborn lambs and adult sheep. Administration of the nonsulfhydryl-containing converting-enzyme inhibitor enalapril reduced mean arterial pressure in the newborn but not in the adult animals. Blood pressure fell in both age groups after hemorrhage, and the hemorrhage-induced fall in blood pressure, integrated over the period of hypovolemia, was more pronounced when converting-enzyme inhibition was present in the lambs. This was not observed in the adults. Cardiac output fell following hemorrhage in both age groups, and themore » fall was greater when enalapril was present in the lambs, but this was not the case in the adults. Hemorrhage increased plasma renin activity in both groups, and enalapril augmented this increase. Plasma concentrations of vasopressin, measured by radioimmunoassay, and catecholamines measured by radio enzymatic assay, increased following hemorrhage within and between groups. Taken together these data suggest that the renin-angiotensin systems plays a more important role in the maintenance of cardiovascular homeostasis in newborn lambs than it does in adult sheep, and catecholamine and vasopressin responses to volume loss can occur in the presence of blockade of the renin-angiotensin system.« less