Effect of Hormonal Environment on Sterol Concentrations of Rat Aorta and Plasma

Fuller, Gene B.; Wilson, Robert O.

doi:10.1159/000178656

Cited by 2 publications

(2 citation statements)

References 14 publications

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“…These observations lend additional support to research evidence implicating serum lipids as the impetus for atheromatous disease. The similarity between CON and CAP lipid levels was unexpected, and it is in disagreement with numerous human and animal research endeavors showing significant changes in serum cholesterol, triglycerides, and total lipid following castration (Fillios, 1957;Weiss and Fisher, 1959;Fuller and Wilson, 1975). These findings do, however, support data obtained by Zondek and Marx (1939), which indicated that neither testosterone nor progesterone administration to White Leghorn cocks produced any signs of hyperlipidemia.…”

Section: Discussioncontrasting

confidence: 57%

Effects of Caponization on Body Weight, Atherosclerosis, and Cardiovascular Variables in Hypertensive and Hypotensive Turkey Lines

et al. 1985

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Effects of caponization and blood pressure selection on serum lipids, severity of atherosclerosis, body weight, hematocrit, and relative ventricular weight in hypertensive and hypotensive lines of turkeys were evaluated in two trials. At 8 weeks of age, half the turkeys from each line were caponized. Body weights, blood pressure, and blood samples were obtained from each treatment at 8, 20, and 30 weeks of age. A total of 56 and 72 birds were used in Trials 1 and 2, respectively. Birds were necropsied at 30 weeks of age. Hypertensive turkeys had significantly greater serum cholesterol and total lipid than hypotensive turkeys only at 30 weeks of age in Trial 1. Lower relative ventricular weights were observed in hypotensive turkeys within both trials. Hypertensive birds exhibited a more severe degree of atherosclerosis and higher relative heart weight than hypotensive turkeys. Caponization significantly increased total serum lipid only at 20 weeks of age in Trial 2. Average body weight of caponized turkeys was significantly lower (1.2) than the control turkeys at 30 weeks of age. Caponized turkeys exhibited lower relative ventricular weight in Trial 1 but not Trial 2 and an increase in blood pressure only in Trial 2. Caponization suppressed body weight, decreased hematocrit values, and had no significant effect upon plaque severity. The presence or absence of male sex hormones had virtually no effect on proposed atherogenic stimuli thereby suggesting another mechanism by which the female is afforded a higher degree of protection.

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Section: Discussioncontrasting

confidence: 57%

Effects of Caponization on Body Weight, Atherosclerosis, and Cardiovascular Variables in Hypertensive and Hypotensive Turkey Lines

et al. 1985

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“…Alternatively, estrogen-induced changes in vascular smooth muscle cell membranes may alter the micro-environment and, hence, the conformation of the receptor. Effects by estrogens on such general membrane properties as transmembrane potential (Harder and Coulson, 1979) and sterol content (Fuller and Wilson, 1975) have been demonstrated in vascular smooth muscle. Although such changes could be brought about indirectly through general metabolic effects, the demonstration that estrogen receptors exist in vascular smooth muscle (Harder and Coulson, 1979) makes the probability of a direct cellular effect more likely.…”

Section: Discussionmentioning

confidence: 99%

Increased vascular catecholamine sensitivity and alpha-adrenergic receptor affinity in female and estrogen-treated male rats.

Colucci¹,

Gimbrone²,

McLaughlin³

et al. 1982

Circulation Research

146

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Clinical and experimental observations suggest that female sex hormones, and in particular estrogens, increase vascular sensitivity to catecholamines. We confirmed these conclusions by demonstrating in vitro that segments of small mesenteric arteries (190-290 fim in inside diameter) from male rats treated with 17/?-estradiol (10 jug/100 g body weight per day for 5-7 days) exhibited a 3.2-fold leftward shift in the contractile dose-response curve for norepinephrine, the concentration resulting in half maximal contraction decreasing from a control value of 8.4 X 10"' to 2.6 X 10~7 M. The molecular mechanisms which account for this increase in vascular smooth muscle catecholamine sensitivity are unknown. To evaluate directly the possibility that the effects of female sex hormones on the vascular sensitivity to catecholamines are mediated through changes in the a-adrenergic receptor, radioligand-binding studies using the a-1 subtype-selective ligand [ 3 H]-WB-4101 were performed on homogenates of mesenteric arteries in control and estrogen-treated male rats, and in control and oophorectomized female rats. Following estrogen treatment (250 jug/100 g body weight), receptor affinity in male rats was increased 1.9-fold for the antagonist [ 3 H]-WB-4101, and receptor density decreased slightly, from 102 ± 4 to 85 ± 5 fmol/mg protein. Estradiol at doses of 10 and 250 ftg/100 g body weight increased receptor affinity for the agonist (-)-epinephrine 2.8-and 5.7-fold, respectively. The lower dose of estradiol also increased receptor affinity for (-)-norepinephrine 4-fold. In female rats, the affinities for [ 3 H]-WB-4101 and (-)-epinephrine were 1.6-and 3.5fold higher, respectively, than in age-matched males, with no difference in receptor density between the sexes. Following oophorectomy, the affinity for (-)-epinephrine in females was the same as in males. Testosterone treatment did not affect the density or affinity of receptors in females. These observations demonstrate that estrogens increase the affinity of a-adrenergic receptors in blood vessels, and provide evidence that the estrogen-induced increase in vascular sensitivity to catecholamine-induced contraction is mediated, at least in part, by these affinity changes.

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Effect of Hormonal Environment on Sterol Concentrations of Rat Aorta and Plasma

Cited by 2 publications

References 14 publications

Effects of Caponization on Body Weight, Atherosclerosis, and Cardiovascular Variables in Hypertensive and Hypotensive Turkey Lines

Effects of Caponization on Body Weight, Atherosclerosis, and Cardiovascular Variables in Hypertensive and Hypotensive Turkey Lines

Increased vascular catecholamine sensitivity and alpha-adrenergic receptor affinity in female and estrogen-treated male rats.

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