Gender differences in renal tubular taurocholate transport

Let's talk about sex: Differences in drug therapy in males and females

Professor Henry Higgins in My Fair Lady said, 'Why can't a woman be more like a man?' Perhaps unintended, such narration extends to the reality of current drug development. A clear sex-gap exists in pharmaceutical research spanning from preclinical studies, clinical trials to post-marketing surveillance with a bias towards males. Consequently, women experience adverse drug reactions from approved drug products more often than men. Distinct differences in pharmaceutical response across drug classes and the lack of understanding of disease pathophysiology also exists between the sexes, often leading to suboptimal drug therapy in women. This review explores the influence of sex as a biological variable in drug delivery, pharmacokinetic response and overall efficacy in the context of pharmaceutical research and practice in the clinic. Prospective recommendations are provided to guide researchers towards the consideration of sex differences in methodologies and analyses. The promotion of disaggregating data according to sex to strengthen scientific rigour, encouraging innovation through the personalisation of medicines and adopting machine learning algorithms is vital for optimised drug development in the sexes and population health equity.

Nongenomic effects of estradiol vs. the birth control estrogen ethinyl estradiol on signaling and cell proliferation in pituitary tumor cells, and differences in the ability of R-equol to neutralize or enhance these effects

Ethinyl estradiol (EE2, the active component of many birth control formulations) persists in treated waste waters and it has become a concerning endocrine-disrupting contaminant throughout the world. Previous studies have not examined the behavior of EE2 in nongenomic signaling pathways and the subsequent functional responses (either alone or in mixtures) or conducted comparisons with the physiological estrogen estradiol (E2). In this study, mitogen-activated protein kinases (MAPKs), ERK, and JNK were activated in pituitary tumor cells by fM EE2, but p38 activation was insensitive to Collapse

Key Words

• Calcium
• ERK JNK p38 activation
• Ethinyl estradiol
• G(α)i
• Kinase
• Membrane ERα
• Non-genomic effect
• Phytoestrogen
• Prolactin
• R-equol

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MESH Headings

• Cell Proliferation/drug effects
• Ethinyl Estradiol/pharmacology
• Pituitary Neoplasms/metabolism
• Pituitary Neoplasms/pathology
• Pituitary Neoplasms/drug therapy
• Estradiol/pharmacology
• Estradiol/metabolism
• Animals
• Signal Transduction/drug effects
• Cell Line, Tumor
• Rats
• Prolactin/metabolism
• Humans

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Grants

• R01 ES015292 NIEHS NIH HHS

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Affiliation(s)

Manish Kumar Saraf Department of Biochemistry & Molecular Biology, University of Texas Medical Branch Galveston, TX 77555-0645, United States
Yow-Jiun Jeng Department of Biochemistry & Molecular Biology, University of Texas Medical Branch Galveston, TX 77555-0645, United States
Cheryl S Watson Department of Biochemistry & Molecular Biology, University of Texas Medical Branch Galveston, TX 77555-0645, United States.

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Metabolomic profiles associated with all-cause mortality in the Women's Health Initiative

BACKGROUND

Metabolomics profiling has shown promise in elucidating the biological pathways underpinning mortality, but there are limited data in female populations.

METHODS

We applied a liquid chromatography-tandem mass spectrometry metabolomics platform to EDTA-plasma to measure 470 metabolites at baseline in a discovery set of 943 postmenopausal women (including 417 incident deaths, median time to death of 10.6 years) with validation in an independent set of 1355 postmenopausal women (including 685 deaths, median time to death of 9.1 years) in the Women's Health Initiative.

RESULTS

Eight new metabolites were discovered to be associated with all-cause mortality. Findings included protective effects of increased levels of three amino acids (asparagine, homoarginine and tryptophan) and docosatrienoic acid; and detrimental effects of increased levels of C4-OH-carnitine, hexadecanedioate and two purine/pyrimidines (N2, N2-dimethylguanosine and N4-acetylcytidine). In addition, a set of nine previously published metabolite associations were replicated. A metabolite score comprising 17 metabolites was associated with mortality (P < 10-8) after adjustment for risk factors, with a hazard ratio of 1.95 (95% CI: 1.46-2.62) for women in the highest quartile compared with the lowest quartile of metabolite score. The score was robust among younger women and older women, for both cardiovascular and non-cardiovascular mortality, and associated with both early deaths (within the first 10 years of baseline) and later deaths.

CONCLUSIONS

Our study fills a gap in the literature by identifying eight novel metabolite associations with all-cause mortality in women, using a robust study design involving independent discovery and validation datasets.

Influence of estrogen and xenoestrogens on basolateral uptake of tetraethylammonium by opossum kidney cells in culture

The sex steroid hormone estrogen down-regulates renal organic cation (OC) transport in animals, and it may contribute to sex-related differences in xenobiotic accumulation and excretion. Also, the presence of various endocrine-disrupting chemicals, i.e., environmental chemicals that possess estrogenic activity (e.g., xenoestrogens) may down-regulate various transporters involved in renal accumulation and excretion of xenobiotics. The present study characterizes the mechanism by which long-term (6-day) incubation with physiological concentrations of 17beta-estradiol (E(2)) or the xenoestrogens diethylstilbestrol (DES) and bisphenol A (BPA) regulates the basolateral membrane transport of the OC tetraethylammonium (TEA) in opossum kidney (OK) cell renal cultures. Both 17beta-E(2) and the xenoestrogen DES produced a dose- and time-dependent inhibition of basolateral TEA uptake in OK cell cultures, whereas the weakly estrogenic BPA had no effect on TEA uptake. Treatment for 6 days with either 1 nM 17beta-E(2) or DES reduced TEA uptake by approximately 30 and 40%, respectively. These effects were blocked completely by the estrogen receptor antagonist ICI 182780 (Faslodex, fulvestrant), suggesting that these estrogens regulate OC transport through the estrogen receptor, which was detected (estrogen receptor alpha) in OK cell cultures by reverse transcription-polymerase chain reaction. The J(max) value for TEA uptake in 17beta-E(2)- and DES-treated OK cell cultures was approximately 40 to 50% lower than for ethanol-treated cultures, whereas K(t) was unaffected. This reduction in transport capacity was correlated with a reduction in OC transporter OCT1 protein expression following treatment with both agents.

Gender differences in kidney function

Sex hormones influence the development of female (F) and male (M) specific traits and primarily affect the structure and function of gender-specific organs. Recent studies also indicated their important roles in regulating structure and/or function of nearly every tissue and organ in the mammalian body, including the kidneys, causing gender differences in a variety of characteristics. Clinical observations in humans and studies in experimental animals in vivo and in models in vitro have shown that renal structure and functions under various physiological, pharmacological, and toxicological conditions are different in M and F, and that these differences may be related to the sex-hormone-regulated expression and action of transporters in the apical and basolateral membrane of nephron epithelial cells. In this review we have collected published data on gender differences in renal functions, transporters and other related parameters, and present our own microarray data on messenger RNA expression for various transporters in the kidney cortex of M and F rats. With these data we would like to emphasize the importance of sex hormones in regulation of a variety of renal transport functions and to initiate further studies of gender-related differences in kidney structure and functions, which would enable us to better understand occurrence and development of various renal diseases, pharmacotherapy, and drug-induced nephrotoxicity in humans and animals.

Renal expression of organic anion transporter OAT2 in rats and mice is regulated by sex hormones

The renal reabsorption and/or excretion of various organic anions is mediated by specific organic anion transporters (OATs). OAT2 (Slc22a7) has been identified in rat kidney, where its mRNA expression exhibits gender differences [females (F) > males (M)]. The exact localization of OAT2 protein in the mammalian kidney has not been reported. Here we studied the expression of OAT2 mRNA by RT-PCR and its protein by Western blotting (WB) and immunocytochemistry (IC) in kidneys of adult intact and gonadectomized M and F, sex hormone-treated castrated M, and prepubertal M and F rats, and the protein in adult M and F mice. In adult rats, the expression of OAT2 mRNA was predominant in the outer stripe (OS) tissue, exhibiting 1) gender dependency (F > M), 2) upregulation by castration and downregulation by ovariectomy, and 3) strong downregulation by testosterone and weak upregulation by estradiol and progesterone treatment. A polyclonal antibody against rat OAT2 on WB of isolated renal membranes labeled a approximately 66-kDa protein band that was stronger in F. By IC, the antibody exclusively stained brush border (BB) of the proximal tubule S3 segment (S3) in the OS and medullary rays (F > M). In variously treated rats, the pattern of 66-kDa band density in the OS membranes and the staining intensity of BB in S3 matched the mRNA expression. The expression of OAT2 protein in prepubertal rats was low and gender independent. In mice, the expression pattern largely resembled that in rats. Therefore, OAT2 in rat (and mouse) kidney is localized to the BB of S3, exhibiting gender differences (F > M) that appear in puberty and are caused by strong androgen inhibition and weak estrogen and progesterone stimulation.