Cholesterol limits estrogen uptake by liposomes and erythrocyte membranes

Jacobsohn, Myra K.; Bauder, Sally; Pine, Sharon R.; Jacobsohn, Gert M.

doi:10.1016/0005-2736(94)90019-1

Cited by 14 publications

(14 citation statements)

References 30 publications

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“…Blood cells carry a significant proportion of sex hormones, as previously observed for cortisol [17] and estrogens [19], in a way that simple plasma/serum analyses leave behind a significant proportion (about 1/4 or more) of blood hormone. It may be suggested that RBC-carried hormones, because of their binding to the cells should be less dynamic than the free hormone or that bound non-specifically to most plasma proteins, in closer contact with the free hormone.…”

Section: Discussionmentioning

confidence: 57%

“…This is a question that should be taken into account by clinicians and investigators measuring serum hormone levels, and is a source of variability (and perhaps of endocrine significance) which is more than often overlooked, in a similar way to the compartment we have analyzed and brought to scrutiny: the blood cell hormone compartment. This, in itself may be also modulated by packed cell volume, but more probably by a different membrane affinity for steroid hormones, a consequence of their structure or, more probably of the previous binding of other steroids, such as cholesterol [19] or, more probably, estradiol itself [18], which may help explain the sex-related differences in the size of the RBC compartment for all the hormones studied.…”

Section: Discussionmentioning

confidence: 99%

“…The presence of steroid hormones in RBC has been known for a time [17], and the possibility of their binding [23], [24], transport [19] or implication in membrane structure [20], [25] have been already advanced by different groups of investigators. However, the extent and possible equilibrium role of the RBC-bound hormone compartment has not been –to our knowledge— investigated, and neither have the effects of diet and sex.…”

Section: Discussionmentioning

confidence: 99%

“…Their relative structural similarity to cholesterol and usually high lipophilic nature help reinforce this assumption. In fact there is a number of studies describing the association of steroid hormones [18], [19] and cell membranes. The direct biophysical interaction of some hormones, such as estradiol and membranes has been also analyzed [20].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Sex and Prior Exposure to a Cafeteria Diet on the Distribution of Sex Hormones between Plasma and Blood Cells

et al. 2012

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It is generally assumed that steroid hormones are carried in the blood free and/or bound to plasma proteins. We investigated whether blood cells were also able to bind/carry sex-related hormones: estrone, estradiol, DHEA and testosterone. Wistar male and female rats were fed a cafeteria diet for 30 days, which induced overweight. The rats were fed the standard rat diet for 15 additional days to minimize the immediate effects of excess ingested energy. Controls were always kept on standard diet. After the rats were killed, their blood was used for 1) measuring plasma hormone levels, 2) determining the binding of labeled hormones to washed red blood cells (RBC), 3) incubating whole blood with labeled hormones and determining the distribution of label between plasma and packed cells, discounting the trapped plasma volume, 4) determining free plasma hormone using labeled hormones, both through membrane ultrafiltration and dextran-charcoal removal. The results were computed individually for each rat. Cells retained up to 32% estrone, and down to 10% of testosterone, with marked differences due to sex and diet (the latter only for estrogens, not for DHEA and testosterone). Sex and diet also affected the concentrations of all hormones, with no significant diet effects for estradiol and DHEA, but with considerable interaction between both factors. Binding to RBC was non-specific for all hormones. Estrogen distribution in plasma compartments was affected by sex and diet. In conclusion: a) there is a large non-specific RBC-carried compartment for estrone, estradiol, DHEA and testosterone deeply affected by sex; b) Prior exposure to a cafeteria (hyperlipidic) diet induced hormone distribution changes, affected by sex, which hint at sex-related structural differences in RBC membranes; c) We postulate that the RBC compartment may contribute to maintain free (i.e., fully active) sex hormone levels in a way similar to plasma proteins non-specific binding.

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Section: Discussionmentioning

confidence: 57%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Sex and Prior Exposure to a Cafeteria Diet on the Distribution of Sex Hormones between Plasma and Blood Cells

et al. 2012

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“…Also, estrogen has been shown to have the capacity to associate with the cell surface and to intercalate into the plasma membrane (54), so the lipophilicity of estrogen may be one of the many mechanisms making this compound ideal for preventing lipid peroxidation. Alternatively, estrogen may act indirectly in attenuating oxidative stress.…”

Section: Estrogen As An Anti-oxidantmentioning

confidence: 99%

Estrogen as a Multi-Active Neuroprotective Agent in Traumatic Injuries

2004

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In the past decade, research has demonstrated that estrogen's role in physiology and development is far more complicated than previously assumed. Among these discoveries, there has been an increased recognition of the impact estrogen has in neurodevelopment, central nervous system physiology, and neuropathophysiology. These observations have led many researchers to consider using estrogen pharmacotherapeutically, at physiologic or supraphysiologic doses, for a variety of injury and toxicity models. In this short review, the effects of estrogen as an anti-apoptotic agent, as an anti-oxidant, and as an anti-inflammatory agent are discussed. Finally, the possibility of using estrogen as a neuroprotectant in neurotrauma is addressed.

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