The normal increase in insulin after a meal may be required to prevent postprandial renal sodium and volume losses

Despite the effects of insulinopenia in type 1 diabetes and evidence that insulin stimulates multiple renal sodium transporters, it is not known whether normal variation in plasma insulin regulates sodium homeostasis physiologically. This study tested whether the normal postprandial increase in plasma insulin significantly attenuates renal sodium and volume losses. Rats were instrumented with chronic artery and vein catheters, housed in metabolic cages, and connected to hydraulic swivels. Measurements of urine volume and sodium excretion (UNaV) over 24 h and the 4-h postprandial period were made in control (C) rats and insulin-clamped (IC) rats in which the postprandial increase in insulin was prevented. Twenty-four-hour urine volume (36 ± 3 vs. 15 ± 2 ml/day) and UNaV (3.0 ± 0.2 vs. 2.5 ± 0.2 mmol/day) were greater in the IC compared with C rats, respectively. Four hours after rats were given a gel meal, blood glucose and urine volume were greater in IC rats, but UNaV decreased. To simulate a meal while controlling blood glucose, C and IC rats received a glucose bolus that yielded peak increases in blood glucose that were not different between groups. Urine volume (9.7 ± 0.7 vs. 6.0 ± 0.8 ml/4 h) and UNaV (0.50 ± 0.08 vs. 0.20 ± 0.06 mmol/4 h) were greater in the IC vs. C rats, respectively, over the 4-h test. These data demonstrate that the normal increase in circulating insulin in response to hyperglycemia may be required to prevent excessive renal sodium and volume losses and suggest that insulin may be a physiological regulator of sodium balance

Bakteri Tanah Sampah Pendegradasi Plastik dalam Kolom Winogradsky

Penggunaan plastik berupa kantong kresek hasil daur ulang dengan berbagai warna sangat diminati oleh masyarakat. Sifat plastik yang tidak mudah terdegradasi di alam mengakibatkan masalah lingkungan. Penelitian ini dilakukan untuk mengisolasi dan mengkarakterisasi bakteri tanah sampah yang mampu mendegradasi plastik secara biokimia. Parameter biodegradasi plastik yang diukur adalah prosentase kehilangan berat kering, pengukuran densitas sel biofilm, densitas sel kolom air dan pH tiap bulan selama 4 bulan masa inkubasi. Dari penelitian didapatkan persentase kehilangan berat kerig plastk hitam lebih tinggi daripada plastik putih Bening. Hasil yang diperoleh menunjukkan bahwa isolat bakteri tanah sampah pendegradasi plastik yaitu Gram positif basil (PPs 2, PPs 7, PPs 9, dan PPs 11) dan Gram negatif basil (PPs 1, PPs 4, PPs 5, PPs 6, PPs 8, PPs 10, PPs 12 dan PPs 13 )dan hanya PPs 3 termasuk Gram negatif kokus

Classical estrogen receptors and ERα splice variants in the mouse.

Estrogens exert a variety of effects in both reproductive and non-reproductive tissues. With the discovery of ERα splice variants, prior assumptions concerning tissue-specific estrogen signaling need to be re-evaluated. Accordingly, we sought to determine the expression of the classical estrogen receptors and ERα splice variants across reproductive and non-reproductive tissues of male and female mice. Western blotting revealed that the full-length ERα66 was mainly present in female reproductive tissues but was also found in non-reproductive tissues at lower levels. ERα46 was most highly expressed in the heart of both sexes. ERα36 was highly expressed in the kidneys and liver of female mice but not in the kidneys of males. ERβ was most abundant in non-reproductive tissues and in the ovaries. Because the kidney has been reported to be the most estrogenic non-reproductive organ, we sought to elucidate ER renal expression and localization. Immunofluorescence studies revealed ERα66 in the vasculature and the glomerulus. It was also found in the brush border of the proximal tubule and in the cortical collecting duct of female mice. ERα36 was evident in mesangial cells and tubular epithelial cells of both sexes, as well as podocytes of females but not males. ERβ was found primarily in the podocytes in female mice but was also present in the mesangial cells in both sexes. Within the renal cortex, ERα46 and ERα36 were mainly located in the membrane fraction although they were also present in the cytosolic fraction. Given the variability of expression patterns demonstrated herein, identification of the specific estrogen receptors expressed in a tissue is necessary for interpreting estrogenic effects. As this study revealed expression of the ERα splice variants at multiple sites within the kidney, further studies are warranted in order to elucidate the contribution of these receptors to renal estrogen responsiveness

ERα66 protein level in various organs of mice.

<p>Shown are representative Western blots and quantification for expression in non-reproductive and reproductive organs harvested from female and male mice. Data are shown as percent of ERα66 in female kidney, plotted on a logarithmic scale. *<i>P</i><0.05 vs. female kidney, <b>^†</b><i>P</i><0.05 vs. female liver, ^¶<i>P</i><0.05 vs. female heart (<i>n</i> = 4–5 per group).</p

ERα46 and ERα36 protein level in membrane and cytosolic fractions from the renal cortices of female mice.

<p>Shown are representative Western blots and quantification for ERα splice variant expression in membrane and cytosolic fractions from the renal cortices from female mice. *<i>P</i><0.05 vs. membrane fraction.</p

ERβ protein level in various organs of mice.

<p>Shown are representative Western blots and quantification for expression in non-reproductive and reproductive organs harvested from female and male mice. Data are shown as percent of ERβ in female kidney. *<i>P</i><0.05 vs. female kidney, ^§<i>P</i><0.05 vs. male liver, <b>^†</b><i>P</i><0.05 vs. female liver, ^¶<i>P</i><0.05 vs. heart (of same sex), ^¥<i>P</i><0.05 vs. ovary (<i>n</i> = 4 per group).</p

Representative immunofluorescence images localizing ERα36 in mouse kidney.

<p>Green fluorescence represents ERα36 in all images. Red fluorescence represents cell specific markers for co-localization (collecting duct marker, aquaporin 2; vascular smooth muscle & mesangial cell marker, α-smooth muscle actin; podocyte cell marker, synaptopodin). Nuclei are stained blue with DAPI. Scale bar = 20 µm.</p