The differential impact of COVID-19 across health service psychology students of color: An embedded mixed-methods study

OBJECTIVES

Communities of color in the United States systematically experience inequities in physical and mental health care compared to individuals who identify as non-Hispanic White. The coronavirus disease 2019 (COVID-19) pandemic exacerbated these structural drivers of inequity to disproportionate and devastating effects for persons of color. In addition to managing the direct effects of COVID-19 risk, persons of color were also navigating increased racial prejudice and discrimination. For mental health professionals and trainees of color, the effects of COVID-19 racial health disparities and the increase in acts of racism may have been compounded by their work responsibilities. The current study used an embedded mixed-methods approach to examine the differential impact of COVID-19 on health service psychology (HSP) students of color as compared to their non-Hispanic White peers.

METHOD

Using quantitative and qualitative data from the Epidemic-Pandemic Impacts Inventory, measures of perceived support and of discrimination, and open-ended questions about students' experiences with racism and microaggressions, we examined the extent to which different racial/ethnic HSP student groups experienced COVID-19-related discrimination, the impacts of COVID-19 felt by students of color, and how these experiences differed from those of their non-Hispanic White peers.

RESULTS

HSP students of color endorsed greater impacts of the pandemic on both self and others in the home, perceived themselves as less supported by others, and reported more experiences of racial discrimination than non-Hispanic White HSP students.

CONCLUSION

Throughout the graduate experience, HSP students of color and their experiences of discrimination need to be addressed. We provided recommendations to HSP training program directors and students both during and after the COVID-19 pandemic.

Age-related differences in memory for "who," "when," and "where" are detectable in middle-aged adults

Our study examined age-related differences across the adult lifespan using a recently developed test assessing memory for "who, when, and where" in addition to associations among these elements. Young (ages 18-25), middle-aged (ages 40-55), and older adults (ages 60+) were asked to remember a sequence of pictures of different faces paired with different places and place the pairs in the correct sequence. Young adults remembered significantly more face-place pairs in the correct sequence than middle-aged (p < .05) and older adults (p < .05), but there were no significant differences between middle-aged and older adults. Furthermore, young adults remembered significantly more face-place pairs irrespective of sequence than older adults (p < .05). However, there were no other significant differences among the groups.Using a rapidly administered test that integrates aspects of everyday episodic memory, we found evidence for age-related differences in test performance beginning in middle age.

Bridging the gap between performance-based assessment and self-reported everyday functioning: An ecological momentary assessment approach

Objective: In the real-world environment, multiple and interacting state-dependent factors (e.g., fatigue, distractions) can cause cognitive failures and negatively impact everyday activities. This study used ecological momentary assessment (EMA) and a n-back task to examine the relationship between fluctuating levels of cognition measured in the real-world environment and self-report and performance-based measures of functional status.Method: Thirty-five community-dwelling older adults (M age = 71.80) completed a brief battery of objective and self-report measures of cognitive and functional status. After completing 100, 45-second trials to reach stable performance on a n-back task, EMA data collection began. Four times daily for one week, participants received prompts on a tablet to complete a n-back task and a brief survey. From the EMA n-back trials, measures of EMA average performance and intra-individual variability (IIV) across performances were created.Results: For the EMA n-back, the correlation between IIV and EMA average was weak and non-significant. IIV associated with self-report measures, and EMA average with the objective, performance-based functional status composite. Hierarchical regressions further revealed that IIV was a significant predictor of self-reported functional status and cognitive failures over and above EMA average performance and global cognitive status. In contrast, for the objective, functional status composite, IIV did not explain additional variance.Conclusions: The findings suggest that IIV and self-report measures of functional status and cognitive failures may capture a real-world cognitive capacity that fluctuates over time and with context; one that may not easily be captured by objective, performance-based measures designed to assess optimal function.

A-46 Impairments in Memory for “Who”, “When”, and “Where” are Detectable in Middle-Aged Adults

Objective

We conducted a cross-sectional study to examine age-¬related differences in performance on a new test assessing memory for “who, when, and where” and associations among these elements. The test was designed to assess aspects of episodic memory by simulating an everyday experience of meeting a series of different people in different places across time.

Method

Healthy young (ages 18¬-25), middle-aged (ages 40-55), and older adults (ages 60+) were asked to remember a sequence of pictures of different faces paired with different places. After viewing the sequence, the participants were asked to pair each face with the correct place and put the face-place pairs in the correct sequence. Participants also completed a battery of standardized neuropsychological tests.

Results

Young adults remembered significantly more face-place pairs in the correct sequence than middle-aged (p < .05) and older adults (p < .05). There were no significant differences between middle-aged and older adults in the number of face-place pairs in correct sequence. Furthermore, young adults remembered significantly more face-place pairs irrespective of sequence than older adults (p < .05). There were no significant differences between young and middle-aged adults or between middle-aged and older adults in the number of correct face-place pairs irrespective of sequence.

Conclusions

Using a new test that incorporates aspects of episodic memory, we found evidence for age-related differences in test performance beginning in middle age. We found that performance on the test correlated with performance on standardized measures of verbal memory and executive functioning but not visual confrontation naming.

Unsaturated fatty acids synergistically enhance glucocorticoid-induced gene expression

Regulation by unsaturated fatty acids of glucocorticoid-sensitive gene transcription was studied in HeLa cells transiently transfected with a mouse mammary tumour virus-luciferase reporter gene. Arachidonic acid and docosahexaenoic acid by themselves had no effect on basal levels of luciferase expression. However, they were able to enhance dexamethasone-induced transcription by 1.4-2.3 times (25-42 times the control levels) in a dose-dependent manner (ED50: 18 and 8 microM) for arachidonic and docosahexaenoic acid, respectively. The glucocorticoid antagonist RU486 effectively antagonized the dexamethasone response as well as the synergistic effect observed in the presence of arachidonic and docosahexaenoic acids, suggesting that the glucocorticoid receptor was an intermediate in the fatty acid synergism of the dexamethasone response. These studies show that fatty acids may be playing a role in modulating the intracellular steroid hormone signalling pathway to co-regulate a glucocorticoid-sensitive promoter.

Fatty acids: ancestral ligands and modern co-regulators of the steroid hormone receptor cell signalling pathway

Long chain fatty acids derived from endogenous metabolism and/or nutrition are regulators of cell signalling pathways. They can be lipid second messengers of signal transduction systems or modulators and regulators of intracellular signalling pathways such as those involved in the mechanism of action of steroid hormones. Fatty acids have been shown to activate gene transcription under the control of some evolutionarily primitive members of the steroid/thyroid superfamily of receptors. They may represent ancestral ligands of this superfamily of receptors. Fatty acids are also known to regulate the activity of protein kinases, particularly protein kinase C, and thereby phosphorylation of intracellular proteins involved in regulation of gene transcription. Fatty acids may be co-regulators in the cross-talk between membrane-triggered signal transduction and the intracellular steroid hormone signalling pathway. Fatty acids are known to affect either negatively and/or positively the binding of steroid hormones to their specific plasma transport proteins and their specific intracellular receptors and, very recently, fatty acids have also been shown to co-regulate glucocorticoid-dependent gene expression. The mechanism of action of steroid hormones will be used as an illustration of how fatty acids can intervene at different levels of cellular organization to regulate biological activity, with a focus on the glucocorticoid receptor.

Fatty acids and cell signal transduction

Fatty acids released from membrane phospholipids by cellular phospholipases or available to the cell from the extracellular environment are important cell signalling molecules. Fatty acids can act as second messengers involved in the transduction of external signals because their concentrations are rapidly and transiently altered in response to the binding of specific agonists to plasma membrane receptors, and they substitute for the classical second messengers of the inositide phospholipid and the cyclic AMP signal transduction pathways. Fatty acids are also modulators because they act in a reversible manner at a precise intracellular location for a very short time to amplify, attenuate or deviate a signal. Fatty acids modify the activities of phospholipases, protein kinases, G-proteins, adenylate and guanylate cyclases as well as ion channels and other biochemical events involved in stimulus-response coupling mechanisms. The action of fatty acids on signal transduction pathways can be direct and/or indirect (by catabolic conversion of arachidonic acid to eicosanoids). However, a number of studies clearly show that fatty acids per se are messenger and modulator molecules mediating responses of the cell to extracellular signals.

In vivo effect of free fatty acids on the specific binding of glucocorticosteroids to corticosteroid binding globulin and liver receptors in immature rats

Stimulating lipase activity with heparin (200 IU/kg b.w.) increased the plasma free fatty acid (FFA) concentration of immature rats (15 days). The effect of this elevated FFA concentration on glucocorticoid binding to corticosteroid binding globulin (CBG), and liver cytosol glucocorticoid receptor (GR), was analyzed. The plasma FFA concentration increased 2-fold, 10 minutes (P < 0.001), 20 minutes (P < 0.01), and 60 minutes (P < 0.01) post-heparin. The corticosterone (B) and progesterone concentrations were unchanged 60 minutes post-injection. The binding activity of immature rat CBG for B dropped 50% (P < 0.001) 60 minutes post-heparin injection, decreased B binding and increased plasma FFA were correlated (r = -0.8). The decreased B binding resulted from a 2-fold decrease in the apparent number of CBG binding sites; the affinity constant (Ka) remained unchanged. The liver cytosol endogenous FFA content of immature rats was also increased 2-fold, 60 minutes after heparin-induced lipolysis. The increased cytosol FFA, with no significant change in glucocorticoid, was accompanied by a significant decrease in dexamethasone binding to liver cytosol glucocorticoid receptor. The decrease resulted from a significantly lower apparent Ka for dexamethasone and fewer receptor binding sites (n). There was a good inverse correlation between Ka (r = -0.93) and n (r = -0.90) and the increased liver cytosol FFA content. Thus the higher plasma FFA induced in vivo by lipase activation or a standard FFA mixture probably causes conformational changes in CBG and GR, reducing glucocorticoid binding to immature rat CBG and liver GR.

Interaction of unsaturated fatty acids with rat liver glucocorticoid receptors: studies to localize the site of interaction

Polyunsaturated fatty acids have been shown to decrease the binding of [3H]dexamethasone to rat liver glucocorticoid receptors by mixed non-competitive inhibition, suggesting that these fatty acids interact at a site on the receptor different from the hormone binding site. The present study was undertaken to localize the site of interaction of polyunsaturated fatty acids on the receptor by comparing the differential effects of docosahexaenoic acid (a 22-carbon polyunsaturated fatty acid of the series n-3) on antagonist (RU486) and agonist binding, by covalent cross-linking of the hsp 90 and other proteins to the receptor to attempt to mask the site of interaction, by limited trypsinization to cleave the site and by using antibodies against specific epitopes to prevent fatty acid access by steric hindrance. Binding [3H]RU486 was not inhibited by docosahexaenoic acid at a concentration (60 mumol/l) that increases the dissociation constant of [3H]dexamethasone eightfold. Covalent stabilization of the hetero-oligomeric glucocorticoid receptor structure did not keep the fatty acid from inhibiting [3H]dexamethasone binding. The binding to the receptor of monoclonal and polyclonal antibodies against different domains of the receptor did not sterically hinder the fatty acid interaction with the receptor. After limited trypsinization of the receptor, the fatty acid still increased the dissociation rate constant of [3H]dexamethasone binding, indicating that the site of interaction of polyunsaturated fatty acids is on a fragment of the receptor containing the hormone-binding domain and some sequences C-terminal of the DNA-binding domain.

Perturbation of the immunosuppressive action of glucocorticoids in rat thymocytes by liposoluble extracts of serum from AIDS patients

Liposoluble extracts of serum from healthy men and AIDS patients (stages IVC1 and IVD by CDC criteria) inhibited the incorporation of [3H]thymidine into isolated rat thymocytes, but AIDS extracts were less inhibitory, requiring 1.8 times more cortisol in the AIDS extracts than in the healthy extracts to inhibit [3H]thymidine incorporation by 50%. Although the total serum extracts from AIDS patients contained 1.7 times more cortisol than the extracts from healthy controls, the AIDS extracts decreased the binding affinity (Ka) of [3H]dexamethasone to rat thymus glucocorticoid receptors by 50% less than the healthy control extracts. The present study seems to indicate that a substance(s) can be extracted from the serum of AIDS patients that attenuates the inhibitory effect of cortisol on thymocyte proliferation and interferes with the binding of cortisol to the glucocorticoid receptor.

Rapid and long-term effects of 17 beta-estradiol on PIP2-phospholipase C-specific activity of MCF-7 cells

Activity of the enzyme phosphatidylinositol 4,5-bisphosphate phospholipase C (PIP2-PLC) was demonstrated in MCF-7 human breast cancer cell homogenate. The addition of 10(-9) M 17 beta-estradiol to the culture medium elicited in the cells two types of responses depending on the period of exposure. Enzyme activity was rapidly activated at 15 s of incubation. After 5 min, PIP2-PLC activity was inhibited, and this effect continued at least until 24 h of exposure to the hormone. When 17 beta-estradiol was added in vitro to the total homogenate of untreated cells, enzyme activity was stimulated in a dose-dependent manner. These findings indicate that 17 beta-estradiol induces early and long-term modifications of the phosphoinositide signal pathway in intact MCF-7 cells as well as in vitro. The rapidity of the early effect suggests a non-genomic action of estradiol.

Role of fatty acids in signal transduction: modulators and messengers

Many of the steps involved in signal transduction are regulated positively or negatively by fatty acids (FA) per se. FA have been shown to act both as modulators and messengers, particularly of signals triggered at the level of cell membranes. Enzymes and proteins of the cyclic AMP and the protein kinase C signalling pathways and those involving ion fluxes and mobilization are both activated and/or inhibited by FA. FA can also participate in a feedback control mechanism since phospholipases are themselves modulated by FA. FA, particularly arachidonic acid liberated from membrane phospholipids, are also second messengers in signal transduction, and a good example is the activation of protein kinase C by FA. FA play an important role in regulating the transmission of signals from the extracellular environment by acting as modulators and messengers within the complex intracellular network of relays.

Modulation of glucocorticoid binding to rat liver cytosol receptor by lipid-soluble extracts from the serum of AIDS patients

The total liposoluble extract of sera from AIDS patients, IVC1 and IVD stages, containing cortisol and free fatty acids (FFA) inhibited [3H]dexamethasone binding to a lesser extent than did the same quantity of total liposoluble extract of sera from healthy men. FFA isolated from extracts of AIDS sera by Sephadex LH20 chromatography had less effect on [3H]dexamethasone binding to rat liver glucocorticoid receptor than those extracted from sera of healthy men. These results suggest the presence in sera of AIDS patients of a liposoluble substance which could be limiting the inhibitory effect of FFA on [3H]dexamethasone binding to glucocorticoid receptor by inducing a conformational change in glucocorticoid receptor that could alter the biological action of glucocorticoids. The pathological consequence could be the apparent contradiction of high cortisolemia and clinical symptoms of adrenal insufficiency that have been observed in AIDS patients.

New approach to management of intraaortic balloon pumps in patients with peripheral vascular disease: case reports of four patients requiring urgent IABP insertion

Four selected cases of emergent IABP insertion in PV patients are presented. After angiographic documentation of critical iliac stenosis, conservative peripheral angioplasty was performed prior to IABP insertion. No patient experienced a peripheral ischemic event associated with IABP use.

Modulatory effects of unsaturated fatty acids on the binding of glucocorticoids to rat liver glucocorticoid receptors

Binding of the synthetic glucocorticoid dexamethasone to the rat liver cytosol glucocorticoid receptor was inhibited by physiological concentrations of nonesterified fatty acids as a function of increasing dose, degree of unsaturation, and chain length of the fatty acid. Polyunsaturated fatty acids were the most potent inhibitors. Scatchard analysis and Line-weaver-Burk plots of the binding data revealed that both the association constants and number of binding sites decreased and that polyunsaturated fatty acids inhibition was of a mixed non-competitive type. The dissociation rate constant of [3H]dexamethasone from glucocorticoid receptors was increased by up to 10 times in the presence of docosahexaenoic acid, whereas a competitive inhibitor like the glucocorticoid antagonist RU 38486 had no effect. Moreover, sucrose density gradient analysis showed that docosahexaenoic acid inhibited the binding of [3H] dexamethasone to both the 8.8S and 4S forms. The results strongly suggest that unsaturated fatty acids are interacting at a site on the receptor different from the hormone binding site and the heat shock protein and that by binding to a second site unsaturated fatty acids greatly change the conformation of the hormone binding site to reduce its affinity for the hormone, either partially or completely depending on the concentration and the class of the fatty acid.

Stimulation of progesterone receptors by phorbol ester and cyclic AMP in fetal uterine cells in culture

The role of growth factor signal transducers in the induction of the progesterone receptor by epidermal growth factor (EGF) and the potential sites of EGF antagonism by an antiestrogen were studied in fetal uterine cells in culture. The effects of EGF and estradiol were not additive, suggesting that EGF and estradiol are acting through common mechanisms where antiestrogens could possibly intervene. Fetal uterine cells in culture were found to contain specific, high affinity binding sites for [125I]EGF. Estradiol treatment of the cells led to a higher number of binding sites, but the site of action of 4-hydroxytamoxifen is not the EGF receptor because this antiestrogen had no effect on EGF binding. Activation of protein kinase C by a phorbol ester (12-O-tetradecanoylphorbol 13-acetate) increased progesterone receptor levels to a similar extent as EGF or estradiol. Increasing the intracellular cAMP concentrations by either adding dibutyryl cyclic AMP or activating adenylate cyclase with forskolin also raised progesterone receptor concentrations. Neither the phorbol ester nor dibutyryl cAMP had any effect on cell proliferation. 4-Hydroxytamoxifen completely abolished the effects of the phorbol ester and cAMP. In conclusion, the levels of an estrogen-induced steroid hormone receptor can be regulated by molecules involved in the signal transduction pathway of peptide factors. Moreover, in fetal uterine cells, a potent antiestrogen appears to act as a multiple antagonist but only on an estrogen-inducible response.

[Epidermal growth factor induces the progesterone receptor in fetal uterine cells in culture: antagonistic effect of antiestrogens]

Cells isolated from the uterus of the guinea pig foetus can be maintained in culture even through several sub-cultures. In these cells, estradiol increases progesterone receptor concentrations 2 o 3 times, although estradiol has no effect on cell proliferation. Epidermal growth factor (EGF) stimulates both cell proliferation and the progesterone receptor 4-Hydroxytamoxifen, a tamoxifen metabolite and potent anti-oestrogen, completely inhibits the stimulatory effect of EGF on the progesterone receptor but has no effect on the EGF-induced cell growth. These cells have specific binding sites with high affinity for 125I-EGF. Estradiol increases the number of binding sites but does not affect the affinity for EGF. 4-Hydroxytamoxifen has no significant effect on either the number of binding sites or the binding affinity. In conclusion, EGF could be an autocrine or paracrine factor in estrogen-sensitive cells not only as a potent mitogen but also as a factor capable of increasing an estrogen-induced protein like the progesterone receptor. The observation that an anti-estrogen can also act as an "anti-growth factor" suggests a close relationship between estrogens and growth factors.

Antiestrogens antagonize the stimulatory effect of epidermal growth factor on the induction of progesterone receptor in fetal uterine cells in culture

In fetal uterine cells in culture, epidermal growth factor (EGF) increased progesterone receptor concentrations more than 2-fold. Two other growth factors, transforming growth factor-alpha and fibroblast growth factor, were not able to cause the same increase. This response to EGF was dose dependent; a half-maximal effect was obtained at 10(-10) M. The antiestrogens tamoxifen and 4-hydroxytamoxifen were able to antagonize the stimulatory effect of EGF on progesterone receptor concentrations, but they did not affect its mitogenic effect. The inhibitory effect of 4-hydroxytamoxifen depended on concentration; half-maximal inhibition was observed between 0.5-1 X 10(-9) M. 4-Hydroxytamoxifen could completely inhibit the progesterone receptor increase due to EGF even when added to cells already exposed to the growth factor for 6 days. EGF seems to be acting as an estrogen in increasing progesterone receptors in fetal uterine cells, and antiestrogens are potent antagonists of this response, indicating that growth factors may also be involved in some protein-inducing effects of estrogens. Since estrogen receptor levels were at the limits of detectability under all of the experimental conditions studied, nonestrogen receptor-mediated pathways may be involved. These observations show the potential importance of other factors acting in combination with estrogens in the modulation of progesterone receptor levels.

Pharmacodynamic and biological effects of anti-estrogens in different models

The biological response to anti-estrogens is very variable and depends on the animal species considered, the target organ, the parameter studied, and the experimental conditions. Anti-estrogens can bind specifically, (1) to the estrogen receptor, (2) to the typical anti-estrogen specific binding site, and (3) to low density lipoproteins in the plasma. Using a monoclonal antibody against the estrogen receptor, different immunological characteristics of the anti-estrogen-receptor complex can be observed. This difference could explain some of the different biological effects. Studies using different human mammary cancer cell lines (hormone-dependent) show that anti-estrogens are active in decreasing cell proliferation. Also, anti-estrogens can block proteins specifically produced by these cells. Some of these proteins could act as growth or inhibitory factors. Estrogen sulfates are the main precursors of estradiol in breast tissues and this conversion is significantly decreased by anti-estrogens. It is accepted that the main pathway of action of anti-estrogens is through the estrogen receptor, but recent information suggests the possibility that this is not the only step in the mechanism of action of anti-estrogens.

Control of progesterone receptors in fetal uterine cells in culture: effects of estradiol, progestins, antiestrogens, and growth factors

Cells from the fetal uterus of the guinea pig have been grown as monolayer cell cultures both as primary cultures and through several passages. The cells have a fibroblast-like morphology and ultrastructure, and the subcultures are estrogen responsive. Estradiol induced a 2- to 3-fold increase in specific binding of [3H]R5020 by 9 days in culture, with no effect on proliferation. This binding has the characteristics of the progesterone receptor from the fetal guinea pig uterus (saturable, high affinity, specific for progestins). The increase in progesterone receptor depended on the dose of estradiol, with a half-maximal response at about 5 X 10(-11) M. Progesterone receptor concentrations were inhibited to below basal levels by progesterone and R5020 and the nonsteroidal antiestrogens, tamoxifen, and 4-hydroxytamoxifen. Both progestins and antiestrogens antagonized the stimulatory effect of estradiol. None of these compounds had any effect on cell growth. On the other hand, insulin and epidermal growth factor caused a great increase in cell proliferation. Insulin alone had no effect on progesterone receptor concentrations, but epidermal growth factor stimulated the progesterone receptor about as much as estradiol. Furthermore, coincubation of insulin with estradiol produced a synergistic effect. Estrogen receptor levels were low or undetectable at any time in either the primary culture or the subcultures. It is concluded that fetal uterine cells in culture can serve as a good in vitro model for study of the control of the progesterone receptor in a fetal target tissue.

Modulation of the progesterone receptor in the fetal uterus of the progesterone-primed guinea pig in vivo and in organ culture

Guinea pig fetuses were treated with progesterone for 7 days before placing fetal uteri in organ culture to see if progesterone pre-treatment of fetuses in utero would permanently inhibit the spontaneous rise in progesterone receptor which occurs in organ culture. The data show that: the basal level of progesterone receptor in fetal uteri was not affected by the progesterone treatment and progesterone receptor concentrations in vitro were also not inhibited. When guinea pig fetuses were treated sequentially with progesterone and estradiol, estradiol failed to provoke an uterotrophic effect but it retained its ability to stimulate progesterone receptor concentrations.

4-Hydroxyandrostenedione is not an aromatase inhibitor in the neonatal guinea pig

One-day-old newborn guinea pigs were treated with 4-hydroxyandrostenedione (50 mg/kg body weight/day) for 5 or 12 consecutive days. This compound did not decrease unconjugated or sulfoconjugated estradiol and estrone levels in the plasma or in the uterine tissue itself. It also did not have any effect on uterine wet weight or the estrogen and progesterone receptor concentrations in the uterus. Moreover, progesterone receptor synthesis which is maintained when neonatal uteri are placed in organ culture conditions for 2 days was not affected by the 4-hydroxyandrostenedione treatment.

The complexity of anti-estrogen responses

The actions and biological responses of anti-estrogens are a function of: the experimental conditions, the parameters, the organ and the animal species considered. Target tissues for estrogens in the guinea-pig during the perinatal period are interesting models to explore the action of anti-estrogens. The summary of the data indicates: (1) In the fetal uterus of guinea-pig in in vivo experiments (after injection to the maternal compartment) tamoxifen acts as a real agonist concerning growth, as a partial agonist concerning the stimulation of the progesterone receptor. (2) In in vitro experiments (in organ culture of fetal uterus or in isolated cells) anti-estrogens (tamoxifen or 4-hydroxy-tamoxifen) act as antagonists and also inhibit the effects provoked by estrogens. (3) In the uterus and vagina of newborn guinea-pigs, tamoxifen and its derivatives: 4-hydroxytamoxifen and N-desmethyltamoxifen act as real agonists concerning the uterotrophic and vaginotrophic effects, and also stimulate the amount of DNA per organ, but concerning the progesterone receptor in the uterus, in the short treatment anti-estrogens act as partial agonists but they have no effect in the long treatment. In the vagina in the short treatment anti-estrogens provoke no significant effects, but in the long treatment they are full agonists. In neither of the two biological responses studied (growth and progesterone receptor) does tamoxifen and its derivatives block the action of estradiol. (4) The use of a monoclonal antibody to the estrogen receptor revealed quantitative differences in the activation of the estrogen receptor when bound to estradiol or tamoxifen. This observation was in agreement with the lesser extent of binding to DNA-cellulose of the tamoxifen-estrogen receptor complex as compared with the estradiol-estrogen receptor complex. This fact suggests an impaired activation of the estrogen receptor induced by tamoxifen which might be related to the different biological responses provoked by estrogens and anti-estrogens.

Tamoxifen and progesterone effects in target tissues during the perinatal period

The biological effects of tamoxifen (TAM), progesterone (P), or a combination of TAM + P were investigated in the uterus and vagina of newborn guinea pigs after short (2 days) and long (12 days) treatments. In both tissues, tamoxifen provoked a significant trophic effect which is indicated by the increase in weight, protein and DNA content. In the uterus, progesterone also provoked an increase in weight, protein and DNA content, but much less than that provoked by tamoxifen. In contrast, in the vagina progesterone had no effect on the weight, protein and DNA content, but progesterone did not block the agonistic effect provoked by tamoxifen. The situation was different when progesterone receptor was concerned. Tamoxifen in both tissues (particularly in the vagina) stimulated the progesterone receptor very significantly. Progesterone blocked the number of specific binding sites of progesterone and the stimulatory effect provoked by tamoxifen.

Biological responses of tamoxifen in the fetal and newborn vagina and uterus of the guinea-pig and in the R-27 mammary cancer cell line

The biological and morphological responses of tamoxifen were studied in two models: the uterus and vagina of fetal and newborn guinea-pigs: R-27 cells--a mammary cancer cell line (tamoxifen resistant) derived from the MCF-7 cancer cell line. Tamoxifen (TAM) alone or in combination with estradiol (E2) was administered to pregnant (50-52 days of gestation) or to newborn (2-day-old) guinea-pigs for a long period (12 days). TAM alone produced a great trophic effect on the uterus and vagina which was markedly enhanced when TAM was administered together with E2. Histological studies showed that TAM provokes morphological changes in both the endometria and the myometria and this effect was also greater when TAM was administered together with E2. In the fetal uterus and vagina, the ultrastructural studies showed that TAM induces morphological alterations in different cytoplasmic organelles. This effect was much more intense in newborns where TAM provoked a significant vacuolization of the epithelial cells. Concerning progesterone receptor (PR) in the fetal or newborn tissues (uterus or vagina) TAM provoked a less intense effect than those provoked by E2, but TAM did not block the effect provoked by E2. It was observed that [3H]TAM binds specifically to the estrogen receptor (ER) of fetal guinea pig uterus and this complex is partially recognized by a monoclonal antibody which recognizes the activated form of this receptor, supporting the suggestion that the biological action of TAM is mediated by the ER. The biological and ultrastructural effects provoked by TAM (1 X 10(-6) M), estriol (E3)(5 X 10(-8) M) and the combination of TAM + E3 were studied in the R-27 mammary cancer cell line in culture. E3 stimulated the PR content by 7-10 times. However, TAM did not provoke a significant decrease in the concentration of PR, and in the mixture of TAM + E3 the concentration of PR was of the same order as that in E3 treatment. Ultrastructural observations indicate an intense concentration of ribosomes in the pericytoplasmic area after exposure to E3 and with exposure to TAM an increase in vacuoles and a significant enlargement of the size of the mitochondria were observed. It is concluded that TAM in the target tissues of fetal and newborn guinea pigs acts as a real estrogen and in the R-27 mammary cancer cell line TAM does not block the effect provoked by E3, however it does provoke intense ultrastructural modifications.

Estrogen responsiveness of fetal guinea pig uterine cells in culture

Cells from the uterus of the guinea pig fetus have been grown as a monolayer culture in serum-containing medium. Cells from the first subculture showed high concentrations of progesterone receptor (PR; 9.3-13.8 pmol/mg DNA) even after 9 days in medium containing charcoal-treated serum and estradiol did not induce any further increase. The antiestrogens, tamoxifen and monohydroxytamoxifen, both had an inhibitory effect which could be overcome by estradiol. The progestins, progesterone and R5020, as well as the antiprogestin, RU38486, also decreased the PR concentration. Estrogen receptor (ER) levels did not vary with the compounds tested but were found to be low compared to concentrations found in the fetal guinea pig uterus at 55-65 days of gestation. None of the compounds tested had any effect on the growth of the fetal uterine cells so that the modulation of PR concentrations was dissociated from the regulation of cell growth. It is concluded that estrogens are necessary but not sufficient factors in the control of PR levels in fetal uterine cells. The establishment of a culture system for separate types of fetal uterine cells will permit us to study in vitro the factors involved in the growth effects of estrogens and the control of PR synthesis.

Dynamics and control of progesterone receptor synthesis in the fetal uterus of the guinea-pig in organ culture

Progesterone receptor concentrations increased in fetal guinea-pig uterus in organ culture to as high as 13 X 15 +/- 1 X 22 pmol/mg DNA without any added steroid, although cytosol and nuclear oestrogen receptor levels were very low (0 X 41-1 X 92 pmol/mg DNA). Even after a 3-day exposure to 5 X 10(-8) M-progesterone, which inhibits its own receptor (1 X 14 +/- 0 X 31 pmol/mg DNA), progesterone receptor levels rose to 8 X 58 +/- 1 X 39 pmol/mg DNA when progesterone was removed. This replenishment was inhibited by progesterone and 5 alpha-dihydroprogesterone but was not affected by oestradiol, tamoxifen or dexamethasone. The incorporation of [3H]thymidine into nucleic acids was not decreased by progesterone so that its inhibition of its own receptor in the explants was not due to an inhibition of cell replication. Fetal uterine explants from oestrogen-primed fetuses, after an initial decrease in progesterone receptor, also showed a rise to 7 pmol/mg DNA on day 2 which could be decreased by exposure to progesterone and replenished by removal of this hormone (6-8 pmol/mg DNA), the entire process occurring without apparent oestrogen stimulation. Progesterone rather than oestradiol appears to be a key regulator of progesterone receptor synthesis in the fetal guinea-pig uterus, although oestradiol, along with other factors, may also be involved.

Cytosol and nuclear estrogen receptors (occupied and unoccupied sites) and progesterone receptors in human breast cancer

Estrogen and progesterone receptor concentrations in cytosol and nucleus were measured in 21 primary breast cancer tumors. Twelve out of the 21 tumor samples were cytosol estrogen receptor positive, 8 of which contained only unoccupied estrogen binding sites in the cytosol, but 2 of the 9 'estrogen receptor negative' samples did contain cytosol binding sites already occupied by endogenous hormone. Four other 'estrogen receptor negative' tumors only showed nuclear binding sites. Only 3 of the 12 'estrogen receptor positive' tumors also contained progesterone receptors. All of these tumors also had estrogen receptor in the nucleus. However, three of the 17 'progesterone receptor negative' samples had progesterone receptor only in the nucleus. The present data indicate that 3 possible classes of 'false negative' tumors can be encountered: estrogen receptors occupied by endogenous hormone, tumors containing only nuclear estrogen receptors, and tumors having only nuclear progesterone receptors. Measurement of nuclear estrogen receptor together with the progesterone receptor provides further information on whether the estrogen receptor system is not only present but also functional, and should be of value in the prediction of hormone dependent breast cancer.

Anti-estrogens in fetal and newborn target tissues

The antagonistic effects of progesterone and of the anti-estrogens, tamoxifen and nafoxidine, to estrogen responses were studied in the target tissues of fetal and newborn guinea pigs. In the fetal uterus, progesterone inhibits the stimulatory effect provoked by estradiol on uterine growth, on progesterone receptor and on the acetylation of nuclear histones. Progesterone also blocks the synthesis of new progesterone receptor protein in organ culture. Tamoxifen or nafoxidine (1 or 10 mg/kg/day injected to the mother for 3 days) provoke a uterotrophic effect similar to that of estradiol (1 mg/kg/day injected to the mother for 3 days) but these anti-estrogens have a limited effect on the progesterone receptor. Tamoxifen given together with estradiol antagonizes the effect of the estrogen on the acetylation of histones but the anti-estrogens do not block the effect of estradiol on uterine growth. Histological studies show that both estradiol and tamoxifen provoke a dramatic hypertrophic and hyperplastic effect particularly in the uterine epithelium. In the newborn uterus (6-day old), tamoxifen (s.c. injection of 0.6 micrograms/g body weight) and estradiol (injection of 30 ng/g body weight) provoke a similar uterotrophic effect and both have a limited effect on the progesterone receptor. In the fetal thymus estradiol provokes a selective decrease in the larger and actively proliferating lymphoid cells of the cortical zone. Tamoxifen has a similar effect but to a much lesser extent than estradiol. On the other hand, tamoxifen antagonizes the effect of estradiol on this fetal tissue. It is concluded that during fetal life progesterone antagonizes the effect of estradiol but tamoxifen can act as an agonist or an antagonist of estrogen action which is a function of the type of response or organ considered.

Characteristics of the nuclear translocation of progesterone receptor in fetal guinea pig uterus "in vivo", "in vitro" and in organ culture

The translocation of progesterone receptor from the cytosol into the nucleus was studied under "in vivo" and "in vitro" conditions in the uteri of guinea pig fetuses exposed to progesterone or a synthetic progestin, R5020. Progesterone treatment of estrogen-primed fetuses leads to a rapid (before 1h) transfer of cytosol progesterone receptor into the nucleus which is, however, short-lived (less than 3h). A rapid decrease in the retention of the estrogen receptor in the nucleus also occurs. In the "in vitro" incubations of whole fetal uteri, translocation of progesterone receptor is temperature-dependent and specific for progesterone and R5020; estradiol and cortisol have no effect. Putative progesterone receptors can also be induced in explants of fetal guinea pig uteri in organ culture which translocate from the cytosol into the nucleus under the same "in vitro" conditions as in whole uteri. Fetal uterine progesterone receptor, either stimulated "in vivo" by estrogen-priming or induced in organ culture, translocates from the cytosol into the nucleus and this process seems to be accompanied by a decrease in retention of the estrogen receptor in the nucleus which appears to be the mechanism by which progesterone antagonises estrogen action in fetal guinea pig uterus.

Concentrations of oestradiol and oestrone in plasma, uterus and other tissues of fetal guinea-pigs: their relationship to uptake and specific binding of [3H]oestradiol

The concentrations of unconjugated oestradiol-17 beta and oestrone have been measured by radioimmunoassay in the plasma of fetal, newborn and immature guinea-pigs. In fetal plasma, the values of oestradiol ranged from 15 to 50 pg/ml with no significant variations with gestational age except for an abrupt increase at the very end of gestation (148 pg/ml). Low concentrations of oestradiol were also found postnatally (from not detectable to 31 pg/ml) as well as in maternal plasma (22 pg/ml). The values of oestrone were consistently higher in all plasma regardless of age (43--164 pg/ml). Oestrogen concentrations were also determined in the fetal uterus, lung, kidney and brain and were found to be as much as 60 times higher (per g tissue) than in plasma, especially in the fetal uterus which contained four to five times more than the other tissues. These data correlated well with a 20--90 times greater uptake of [3H]oestradiol by the fetal uterus compared with the other tissues after in-vivo administration of [3H]oestradiol to the fetuses. The selective retention of oestradiol was probably due to the presence of specific oestradiol binding in these fetal tissues, particularly in the uterus whose binding was 60--120 times higher than in the other fetal tissues. Thus, the levels of oestrogen in the circulation of fetal guinea-pigs are low, but the fetal uterus is capable of maintaining a higher concentration which may be important physiologically since oestradiol has been shown to evoke a biological response in the fetal guinea-pig uterus.

Progesterone antagonizes the effects of estradiol in the fetal uterus of guinea pig

The antagonistic effect of progesterone on estrogen responses in the uterus of the guinea pig fetus has been demonstrated. The administration of 5 mg of progesterone to estradiol-primed pregnant guinea pigs inhibits the increase in uterine wet weight normally occurring between 1 and 2 days after estradiol treatment. Progesterone also decreased the concentration of its own receptor by as much as 51%, 4 days after treatment. Progesterone had no effect on the replenishment of estrogen receptor in the cytosol but it induced a rapid decrease in nuclear receptor since 5 days after estradiol treatment the concentration of nuclear estrogen receptor is 2.0 +/- 0.65 pmol/mg DNA while only 24h after progesterone treatment this value is 0.78 +/- 0.10 pmol/mg DNA which is not significantly different from the untreated control values of 0.68 +/- 0.12 pmol/mg DNA. It is concluded that progesterone can antagonize estrogen action in the fetal uterus.

Progesterone and oestradiol receptors in the uterus of oestradiol-primed fetal and newborn guinea-pigs

The responsiveness of the uterus of the guinea-pig to oestrogen treatment was studied in the fetal and perinatal periods. Twenty-four hours after one dose of 1 mg oestradiol/kg body wt to the pregnant guinea-pig, there was no significant increase in uterine wet weight of the fetus but a sevenfold increase in the concentration of progesterone receptors. In the perinatal period, doses of 1, 10 and 100 micrograms oestradiol led to as much as an 80% increase in uterine wet weight after 24 h in both 2- and 7-day-old guinea-pigs. On the other hand, levels of progesterone receptors in newborn animals showed a smaller increase (twofold) than that which occurred in the fetal uterus. In both fetal and newborn guinea-pigs, total oestradiol-receptor concentrations (both available and occupied binding sites) decreased significantly after treatment with oestradiol. It was concluded that the hormonal effect of oestradiol on progesterone-receptor synthesis can be expressed in the fetus and to an even greater extent than in the perinatal period over the same period of time. In the fetus, this response can be distinguished from the overall uterotropic effect of oestradiol.

Specific binding of estrogens in different fetal tissues of guinea pig during fetal development

Cytosol and nuclear specific estradiol binding was evaluated in the fetal uterus, kidney, lung, and brain of guinea pig during fetal development and after birth. The quantity of specific binding sites increases during fetal development and decreases after birth, particularly that of the nuclei. An exception is the binding in the cytosol fraction of lung in which the number of available binding sites continues to increase in newborn animals. In the fetal uterus the amount of specific binding of estradiol and estrone is similar. The selective uptake of radioactivity and its localization by autoradiography in cell nuclei are in accordance with the high levels of estrogen receptors, particularly at the end of gestation.