Effect of Sex and Cross-Sex Hormone Treatment on Renal Monocarboxylate-Transporter Expression in Rats

Abstract

Proton- and sodium-dependent monocarboxylate transporters (MCTs/SMCTs) are determinants of renal clearance through the renal reabsorption of monocarboxylate substrates. Prior studies with intact females and males, ovariectomized females and castrated males have revealed the hormonal regulation of renal monocarboxylate-transporter expression, prompting investigation into the regulatory role of individual hormones. The aim of the present study is to evaluate the effect of exogenous sex and cross-sex hormones on renal MCT1, MCT4, CD147 and SMCT1 mRNA and membrane-bound protein expression. Ovariectomized (OVX) females and castrated (CST) male Sprague Dawley rats received estrogen and/or progesterone, testosterone, or a corresponding placebo treatment for 21 days prior to kidney collection. The quantitative measurement of mRNA and membrane-protein levels were conducted using qPCR and Western blot. Quantitative analysis revealed the combination estrogen/progesterone treatment reduced membrane MCT1 and 4 expression and increased SMCT1 expression, while testosterone administration increased MCT1 membrane-protein expression. Correlation analysis indicated that plasma 17β-estradiol was negatively correlated with MCT1 and MCT4 membrane expression, while testosterone was positively correlated. In contrast, SMCT1 membrane expression was positively correlated with 17β-estradiol and progesterone concentrations. MCT1, MCT4, CD147 and SMCT1 renal expression are significantly altered in response to female and male sex hormones following sex and cross-sex hormone treatment in OVX and CST rats. Further studies are needed to understand the complex role of sex hormones, sex hormone receptors and the impact of puberty on MCT/SMCT regulation.

Sex and Cross-Sex Testosterone Treatment Alters Gamma-Hydroxybutyrate Acid Toxicokinetics and Toxicodynamics in Rats

“…Furthermore, the renal clearance (1.4 ± 0.6 mL/min/kg) and fe (0.44 ± 0.09) exhibited the lowest values in testosterone-treated CST males in comparison to placebo and intact groups ( Table S4 ). This implies a higher extent of renal reabsorption in testosterone-treated CST males, aligning with the higher expression levels of MCT1 and MCT4 identified in their kidneys [ 22 ]. In the rat kidney, testosterone treatment in CST animals displayed significantly upregulated MCT1 and MCT4 protein expression compared to intact animals [ 22 ].…”

“…This implies a higher extent of renal reabsorption in testosterone-treated CST males, aligning with the higher expression levels of MCT1 and MCT4 identified in their kidneys [ 22 ]. In the rat kidney, testosterone treatment in CST animals displayed significantly upregulated MCT1 and MCT4 protein expression compared to intact animals [ 22 ]. One testosterone-treated CST animal was excluded from the analysis due to its weakened capacity for GHB elimination, leading to approximately 50% extrapolation of the AUC, which failed to show the true terminal phase and does not meet the criteria for NCA analysis.…”

“…Testosterone plasma concentrations were quantified using a validated LC-MS assay, as described previously [ 22 ]. In brief, for standard and quality controls, 5 μL of testosterone-D3 and 10 μL of standard or QC stock solution were added to 90 μL of acetonitrile.…”

“…The same LC/MS/MS equipment was used for quantification, as mentioned above. HPLC conditions, mass spectrometer parameters ( Table S2 ), and linear calibration ranges were described in a recent publication [ 22 ].…”

“…The sex-dependent variations in renal MCTs/SMCTs lead to alterations in GHB toxicokinetics and renal clearance [ 21 ]. Moreover, there were significant alterations in renal MCT expression following exogenous sex and cross-sex hormone treatment in ovariectomized (OVX) and castrated (CST) rats [ 22 ]. However, there is a paucity of information regarding the influence of sex and cross-sex hormone treatment on GHB toxicokinetics and toxicodynamics.…”