Sexual hormones modulate compensatory renal growth and function / Las hormonas sexuales modulan el crecimiento renal compensador (CRC) y la función renal en la uninefrectomía (uNx)

The role played by sexual hormones and vasoactive substances in the compensatory renal growth (CRG) that follows uninephrectomy (uNx) is still controversial. Intact and gonadectomized adult Wistar rats of both sexes, with and without uNx, performed at 90 days age, were studied at age 150 days. Daily urine volume, electrolyte excretion and kallikrein activity (UKa) were determined. Afterwards, glomerular filtration rate and blood pressure were measured, the kidneys weighed and DNA, protein and RNA studied to determine nuclei content and cell size. When the remnant kidney weight at age 150 days was compared with the weight of the kidney removed at the time of uNx, male uNx rats showed the greatest CRG (50%) while growth in the other uNx groups was 25%, 15% and 19% in orchidectomized, female and ovariectomized rats, respectively. The small CRG observed in the uNx female rats was accompanied by the lowest glomerular filtration value, 0.56 ± 0.02 ml/min/g kwt compared, with the other uNx groups, p < 0.05. Cell size (protein or RNA/DNA) was similar for all the groups except for uNx orchidectomized rats. In this group the cytoplasmatic protein or RNA content was lower than in the other groups while DNA (nuclei content) was similar. Some degree of hyperplasia was determined by DNA content in the uNx groups. Male sexual hormones positively influenced CRG and its absence modulated cell size. Female sexual hormones, instead, did not appear to stimulate CRG. The kallikrein kinin system may not be involved in CRG.

La importancia que pueden tener las hormonas sexuales y sustancias vasoactivas sobre el crecimiento renal compensador (CRC) que sigue a la uninefrectomía es aún materia de debate. Se estudiaron ratas Wistar de ambos sexos, a los 150 días de vida, intactas y gonadectomizadas con y sin uNx, realizada a los 90 días de vida. Se midió volumen urinario diario y excreción de electrolitos y actividad de kalikreína urinaria. Se midió filtrado glomerular y presión arterial media extrayéndose luego los riñones que fueron pesados y preparados para estudios histológicos y determinación de ADN, ARN y proteínas para estimar contenido nuclear y tamaño celular. El CRC fue calculado comparando el peso del riñón al momento de las uNx (90 dias de vida) con aquel obtenido a los 150 días de vida. En las ratas macho uNx se observó el mayor CRC (50%) mientras que, en los otros grupos uNx solo alcanzó un 25%, 15% y 19%. El filtrado glomerular acompañó los cambios morfológicos observándose el menor filtrado en las ratas hembras uNx respecto al resto de los grupos 0.56 ± 0.02, p < 0.05. El tamaño celular (proteína o ARN/ ADN) fue similar para todos los grupos excepto para los orquidectomizados uNx, cuyo contenido citoplasmático fue menor. El contenido nuclear (ADN) fue semejante en todos los grupos. Se observó que el CRC está influenciado positivamente por las hormonas sexuales masculinas y su ausencia modula el tamaño celular. La falta de hormonas sexuales femeninas, en cambio, afecta negativamente el CRC. El sistema kalikreína kinina no parecería estar involucrado en el CRC.

Renal function in the diabetic pregnant rats

Diabetic nephropathy is associated with increased urinary albumin and reduce kallikrein excretion. Increased activity of the renal kallikrein-kinin system has been suggested as one of the possible mechanisms underlying diabetic hyperfiltration. The present study shown that kallikrein-kinin system is progressively increased in the diabetic-pregnant rats at 7, 14, 21 days; 48 and 7 days after pregnancy (P<0.05 vs Control). However, this increase during diabetic pregnancy did not reached the levels of control pregnancy. On the other hand albumin excretion shown a significant and progressive renal damage in the diabetic state. These findings suggest that the diabetic pregnancy could impair the renal hemodynamic, but, on the other side could modulate the vasodilatador system at pregnancy in the attempt protect the fetus.

Disminución del volumen plasmático y cambios en hormonas vasoactivas en embarazadas de bajo peso / Reduced plasma volume and changes in vasoactive hormones in underweight pregnant women

Background: Pregnant women with low weight/height (wt/ht) have lower plasma volume and reduced birth weight than women with normal wt/ht. Aim: To explore the hormonal mechanisms involved in these alterations. Patients and methods: Plasma volume, and several hormones related to plasma volume regulation were determined in 24 near term pregnant women with low wt/ht and in 30 with normal wt/ht. Results: Newborns's weight, height and ponderal index were reduced in the low wt/ht group. Plasma volume (3042 ñ 101 vs 3631 ñ 101 ml, p< 0.001); plasma renin activity (7.5 ñ 0.9 vs 11.1 ñ 0.9 ng/ml/h, p< 0.01) and aldosterone (428 ñ 47 vs 710 ñ 58 pg/ml, p< 0.001) were significantly reduced in the low wt/ht group. Similar reductions were observed in serum estradiol and progesterone levels. Urinary kallikrein activity (354 ñ 112 vs 824 ñ 134 nmoles/24 h, p< 0.05), 6-keto-prostaglandin F1a (561 ñ 90 vs 1121 ñ 165 ng/24 h, p< 0.05) and thromboxane B2 (110 ñ 29 vs 280 ñ 29 ng/24 h, p< 0.05) were also reduced in low wt/ht women. Conclusions: We postulate that the reduced levels of vasoactive hormones observed in pregnant women with low wt/ht may interfere with plasma volume expansion and, in turn, cause low birth weight

Effect of oral glucose tolerance test on urine sodium excretion in obese and non-obese pre-menopausal females

We have investigated the changes in urinary sodium excretion during an oral glucose tolerance test [OGTT] through the associated changes in plasma atrial naturetic peptide [ANP], endogenous insulin and renal kallikrein excretion, in 10 normatensive obese and 10 healthy non-obese pre-menopausal females. Baseline blood glucose did not differ between obese and non-obese females. Blood glucose levels during the OGTT were significantly higher in obese than in non -obese females [P<0.01]. Obese females had significantly higher values of serum insulin at baseline and 2 hours after oral glucose load in comparison to non-obese females [P<0.01, <0.0001 respectively]. A similar finding was also obtained regarding fasting insulin resistance index [FIRI][P<0.0001] Prior to OGTT, urine sodium and kallikrein excretion did not differ between obese and non-obese subjects. After oral glucose load there were significant reduction of urine sodium [P<0.0001] and kallikrein excretion [P<0.0001] only in non-obese females. Obese females had insignificant decrease in urine sodium excretion and insignificant increase in urine kallikrein excretion. The decrease in urine sodium excretion was similar in obese and non-obese females. The plasma ANP level was significantly higher both in obese [P<0.0001] and non-obese [P<0.0001] females after glucose load. However, the percent increase was less in obese than in non-obese females [P<0.05]. In conclusion, changes in endogenous insulin induced by oral glucose were associated with a similar decrease in urine sodium excretion in obese and non-obese normatensive pre-menopausal females but the decrease was only significant in non-obese females. Insignificant reduction in urine sodium excretion in obese females could be due to the counteracting natriuretic effects of renal kallikrein and ANP

Hormonas vasodilatadoras en la insuficiencia cardíaca crónica: efecto de la inhibición de la enzima convertidora de angiotensina / Vasodilator hormones in chronic heart failure: effect of the inhibition of angiotensine converting enzyme

To evaluate the chronic effect of enalapril, in addition to digitalis and diuretics, in patients with chronic heart failure, nine patients with an idopathic dilated cardiomyopathy (8 males, aged 48 to 76 years old) under treatment with digitalis and diuretics, received enalapril 20 mg bid during eigth weeks. Before and after this treatment period resting left ventricular ejection fraction, functional class, plasma levels of atrial natriuretic factor and bradykinins (BK) and urinary excretion of kalikreins (BK) and prostaglandins E2 (PGE2) were measured. After enalapril therapy, there was a significant increase in maximal O2 consumption (14.8ñ1.2 to 18.6ñ1.5 ml/kg/min, p<0.05) and radionuclide LV ejection fraction (27.4ñ1.1 to 31.4ñ0.9 percent p<0.05). This was associated with a significant decrease in plasma ANP levels (559ñ158 to 178ñ54.8 pg/ml) and UK (391ñ112 to 243ñ92 Cu/24 h). The decrease in ANP levels, which is a well known marker of prognosis in CHF, could contribute to explain the sustained clinical benefits observed with ACE inhibitors in patients with CHF

Kinetic characterization of rat tissue kallikrein using NÓ-substituted arginine 4-nitroanilides and NÓ-benzoyl-L-arginine ethyl ester as substrates

Hydrolysis of seven N(alpha-substituted L-arginine 4-nitroanilides: henzoyl-arginine p-nitroanilide (Bz-Arg-Nan), tosyl-arginine p-nitroanilide (Tos-Arg-Nan), acetyl-leucyl-arginine p-nitroanilide (Ac-Leu-Arg-Nan), acetyl-phenylalanyl-arginine p-nitroanilide (Ac-Phe-Arg-Nan), benzoyl-phenylalanyl-arginine p-nitroanilide (Bz-Phe-Arg-Nan), tosyl-phenylalanyl-arginine p-nitroanilide (Tos-Phe-Arg-Nan), and D-valyl-leucyl-arginine p-nitroanilide (D-Val-Leu-Arg-Nan), and the N(alpha-substituted L-arginine ester: benzoyl-arginine ethyl ester (Bz-Arg-OEt), by rat tissue kallikrein was studied throughout a wide range of substrate concentrations. The enzyme showed a bimodal behavior with all the substrates tested except Tos-Arg-Nan. At low substrate concentrations (10 to 170 muM for p-nitroanilides and 50 to 190 muM for Bz-Arg-OEt) the hydrolysis followed Michaelis-Menten kinetics, but at higher substrate concentrations (150 to 700 muM for p-nitroanilides and 200 to 1800 muM for Bz-Arg-OEt) a deviation from Michaelis-Menten kinetics was observed with a significant decrease in hydrolysis rates. At high concentrations of the p-nitroanilide substrates, partial enzyme inhibition was observed, whereas complete enzyme inhibition was observed with Bz-Arg-OEt at high concentration. The kinetic parameters reported here were calculated from data for substrate concentrations range where the enzyme followed Michaelis-Menten behavior. D-Val-Leu-Arg-Nan (Km = 24 ñ 2 muM; Vmax 10.42 ñ 0.28 muM/min) was the best substrate tested, followed by Ac-Phe-Arg-Nan (Km = 13 ñ 2 muM; Vmax = 3.21 ñ 0.11 muM/min), while Tos-Arg-Nan (Km = 29 ñ 2 muM; Vmax, = 0. 10 ñ 0.002 muM/min) was the worst of the tested substrates for rat tissue kallikrein. For the hydrolysis of Bz-Arg-OEt (Km = 125 ñ 15 muM; Vmax = 121.3 ñ 7.6 muM/min), the kinetic parameters using a substrate inhibition model can reasonably account for the observed enzyme behavior, with a Ksi value about 13.6 times larger than the estimated Km value.

Kinetic mechanism of the inhibition of human urinary kallikrein by basic pancreatic trypsin inhibitor

Hydrolysis of D-valvyl-L-leucyl-L-arginine p-nitroanilide (D-Val-Leu-Arg-Nan) at five different concentration (10-20µM) by human urinary kallikrein was studied in the absence and in the presence of increasing concentrations of basic pancreatic trypsin inhibitor (BPTI) (1.35-9.15nM). The data indicate that the inhbition of human urinary kallikrein by BPTI is not a simple competitive inhibition as reported by others, but that it is a competitive inhibition of the parabolic type, with two inhibitor molecules binding to one enzyme molecule, with the formetion of a ternary enzymatic complex. Statistical analysis of the experimental data supports the kinetic model proposed. The calculated values of the constants Ki and Kii were 16.20 nM and 1.10 nM, repectively. It is noteworthy that the Kii < Ki, i.e., the second BPTI molecule binds to the enzyme with a larger affinity suggesting that this second binding site was probably created or positively modulated as a consequence of the binding of the first BPTI molecule

Streptozotocin induced hyperglycemia is decreased by nitric oxide inhibition

1. Diabetes mellitus type 1 was induced in 3-month old maleC57 BL/KS-mdb mice (N = 24)) by ip injection of streptozotocin (STZ, 45 mg/Kg body weight) for 5 days. 2. To determine the possible protective effects of nitric oxide inhibition against hyperglycemia, the STZ-diabetic rats received two doses of Ng-nitro-l-arginine-methyl ester (L-NAME) (10 mg/Kg body weight and 10 mg/mouse) dissolved in PBS for 45 consecutive days. Another group of STZ-treated rats was similarly treated with L-arginine (5 mg/mouse). 3. Blood glucose levels were 118 ñ 37 mg/dl after 8 days of L-NAME administration (10 mg/Kg body weight, N = 12) and 186 ñ 22 mg/dl (N = 12) after 5 days of L-NAME administration at the 5 mg/mouse dose. Treatment with L-arginine (5-mg/mouse, N = 12) caused a significant increase in blood glucose level to 151 ñ 17,5 mg/dl, showing the relevance of nitric oxide formation in this type of diabetes. 4. In STZ-diabetic mice treated with L-NAME (N = 12), diuresis was reduced by approximately 58 per cents compared to STZ animals, whereas in L-arginine-treated animals (N = 12) diuresis returned to STZ levels. Urinary protein excretion, which, was significantly affected by STZ (123 per cents compared to control) was significanty reduced by 66 per cents after treatment with L-NAME for 45 days, whereas treatment with-L-arginine caused a return to STZ values. 5. Urinary kallikrein excretion, which was reduced by 80 per cents in STZ mice compared to control, returned to control levels after L-NAME treatment. 6. The present results suggest a relationship between nitric oxide levels and the reduction of diabetic state improved renal function by L-name

Chronic indomethacin administration and its relation with the renal kallikrein kinin system during rat pregnancy

Resultados obtenidos en humanos y animales de experimentación muestran un aumento de la excreción de prostaglandinas vasodilatadoras y de Kallikreinas urinarias (KU) durante la preñez dando lugar a una hipótesis dando asignan a estas sustancias participación en la generación de los cambios hemodinámicos relacionados con la gestación. Para dilucidar el posible rol de estos sistemas hormonales se estudiaron ratas preñadas no tratadas y tratadas con indometacina 3mg/Kg/día en dos dosis diarias administradas por vía sc, durante 96 hs entre los días 14 a 18 de preñez. Se coleccionaron muestras de sangre y orina seriadas a lo largo de la preñez midiéndose creatinina en sangre y orina, diuresis de 24 hs, concentración de Kallikreinas urinarias, sodio y potasio. Ratas no preñadas con y sin tratamiento con indometacina, estudiadas en forma similar, se utilizaron como controles (Fig. 1). Las ratas preñadas mostraron un incremento del filtrado glomerular que fue máximo entre los días 14 a 18 de preñez, y descendío luego hacia el final de la gestación (Fig. 2, derecha). Los cambios en las diuresis fueron semejantes a los del clearance de creatinina (Fig. 2, izquierda) encontrándose un incremento de la reabsorción de sodio hacia el fianl de la preñez. La excreción de KU, por su parte, aumentó en la segunda semana de preñez precediendo al pico de hiperfiltración glomerular para luego descender progresivamente (Fig. 3), correlacionándose significativamente con la excreción de sodio (Fig. 4). El tratamiento con indometacina previno el aumento máximo del filtrado glomerular y de la excreción de agua entre los días 14 a 18 de preñez, induciendo un incremento de la excreción de KU y de sodio (Fig.2 y 3) . La falta de incremento del clearance de creatinina y el aumento de la excreción de KU inducidos por el tratamiento con indometacina sugieren que las prostaglandinas vasodilatadoras y el sistema kallikreina kinina renal podrían participar en la regulación de la hiperfiltración gestacional en la rata

Effect of oral potassium supplements on urinary Kallikrein excretion in Sheeha's syndrome

La excrexión urinaria de Klicreína (UKE) es modificada por mineralocorticoides, glucocorticoido del potasio (independiente de su acción sobre aldosterona) sobre la UKE no ha sido evaluado. Para investigar tal acción, se estudió a cuatro pacietnes con síndrome de Sheehan, adecuadamente suplementadas con cortisol y tiroxina, quienes recibieron captopril hasta alcanzar concentraciones muy bajas o no detectables de aldosterona urinaria. Posteriormente, todas ellas recibieron una carga oral de potasio de 30 mmol de KCl dos veces al día, durante dos días consectutivos. La carga oral de potasio no modificó la UKE(F3,9=1,24; p>0,05). El estudio se repitió mientras las pacientes estaban sin cortisol; nuevamente la carga de potasio no cambió la UKE (F3,9 = 2,25; p>0,05). La excreción urinaria de aldosterona no se elevó con la carga oral de potasio, dada bajo el régimen de aporte de cortisol (F3,9 = 1; p>0,05). Sin embargo, cuando la carga de potasio se administró estando suspendido el cortisol, la excreción de aldosterona se elevó significativamente (p<0,025). Estos resultados sugieren que la carga oral de potasio no modifica la UKE, independientemente si la aldosterona es estimulada o no

Nephritis blunts urinary kallikrein excretion and aggravates DOCA/NaCl hypertension in rats

1. Normal rats and passive Heymann membranous glomerulonephritic rats were chronically treated with DOCA/NaCl for 9 weeks. Normal and untreated nephritic rats were used as controls. Urinary kallikrein excretion (UKE), proteinuria and tail blood pressure (BP) were determined in awake rats. Glomuerular filtration rate (GFR), plasma renin activity (PRA), and plasma potassium (PK) concentration were measured at the end of the experiment. 2. Comparasion between basal and 9th-week measurements indicated that DOCA/NaCl administration significantly increased (P < 0.05) UKE (3.96 ñ 0.30 vs 7.60 ñ 1.51 U/24 h) and 118 ñ 2 vs 135 ñ 6 mmHg) in normal rats, whereas in nephritic DOCA/NaCl-treated rats, UKE was unaltered (3.80 ñ 0.50 vs 3.40 ñ 0.30 U/24 h) and BP increased to higher levels (117 ñ 2 vs 152 ñ 3 mmHg) than in the normal DOCA/NaCl group (P < 0.05). Passive Heymann nephritis alone did not affect UKE (3.56 ñ 0.40 vs 3.60 ñ 0.80 /24 h) or BP (124 ñ 2 vs 125 ñ 2 mmØg). At the end of the study, PK was decrease and PRA totally suppressed in both normal and nephritic DOCA/NaCl - treated rats. Proteinuria was more pronounced in nephritic DOCA/NaCl - treated rats (44.8 ñ 5.2 mg/day) than in control nephritic animals (15.1 ñ 2.4 mg/day) and GFR was increased equally in both DOCA/NaCl-treated groups. 4. The failure of nephritic rats respond to DOCA/NaCl by increasing UKE was not associated with any significant derangement of renal function or structure and may have been related to the aggravation of arterial hypertension in this group

Excreción urinaria de calicreína en recién nacidos / Urinary excretion of kallikrein in newborn infants

Se estudió la excreción urinaria de calicreína y algunos parámetros de función renal en 20 recién nacidos (12 RNPT y 8 RNT) de sexo masculino, durante las 24 y 48 horas de vida. Con respecto a los RNT, los RNPT tuvieron excreción urinaria de calicreína más baja (p < 0,05), menor depuración de creatinina (p < 0,02) y más baja osmolaridad urinaria (p <0,03). Los RNPT tuvieron un volumen urinario más alto (p < 0,01), mayor excreción fraccional de sodio (p < 0,01), menor excreción fraccional de potasio (p < 0,05) y mayor depuración de agua libre (p < 0,02). La excreción urinaria de calicreína se correlacionó directamente con edad gestacional (p < 0,01) y peso corporal (p < 0,03), e inversamente con excreción fraccional de sodio (p < 0,04) y volumen urinario (p < 0,01). Al corregir la excreción urinaria de calicreína a superfície corporal, las relaciones pierden significación estadística, excepto con edad gestacional (p < 0,04). Los valores de calicreína urinaria en recién nacido fueron bajos comparados con los de población adulta. Dado que la síntesis de calicreína ocurre en el túbulo distal, se plantea la hipótesis que esta menor excreción en la edad neonatal está relacionada con inmadurez funcional del túbulo, o menor respuesta del nefrón distal a hormonas que se sabe estimulan la excreción urinaria de calicreína en el adulto, como aldosterona y hormona antidiurética, o ambas

Urinary kallikrein: mechanisms of its release and action: review and hypothesis

La calicreína urinaria se origina en el riñon. En esta revisión se postula que la excreción urinaria de calicreína está relacionada con la necesidad de eliminar agua. El principal mecanismo de su liberación es un "lavado" de la calicreína renal producido por el flujo que llega a la célula tabular distal. Diversos sistemas pueden modificar la excreción de calicreína actuando sobre los mecanismos de liberación y/0 síntesis. La calicreína urinaria regula el espacio extracelular inhibiendo la reabsorción distal de agua

Excreción de calicreína urinaria en niños sanos a distintas edades / Urinary kallikrein excretion in healthy children at different ages

La calicreína es una proteína que genera, luego de varias transformaciones, bradicina, una sustancia con potente acción vasodilatadora. En 53 niños de ambos sexos, sanos y normotensos, cuyas edades fluctuaron entre 12 días y 15 años, se midió calicreína urinaria, expresándola en su valor absoluto y en relación a la masa renal. La calicreína urinaria es francamente inferior en el grupo de menores de 6 meses. (0.30 + ou - 0.29 uU 24 hrs.) con respecto a los valores obtenidos en los lactantes y niños mayores (9.46 + ou _ 2.7 y 16.1 + ou - 3,7 uU 24 hrs.). Concluimos que la excreción urinaria de calicreína es significativamente menor en los menores de 6 meses, lo que puede estar relacionada con la maduración renal

Efecto crónico de Li en la presión arterial de rata / Chronic effect of Li ion on the blood pressure of the rat

El ion Li es absorbido con rapidez, se distribuye en todo el organismo y filtra en el glomérulo, pero es reabsorbido en un alto porcentaje por los túbulos. En el presente trabajo se investiga su papel fisiológico en la función renal, en relación con la presión arterial por ingestión crónica; para lo cual se observa presión arterial directa, volúmenes de orina, los electrolitos sodio y potasio y calicreína urinaria. A un grupo de ratas hembras de la cepa Wistar se les trató con solución de LiCl cada 48 horas por vía intragástrica y en forma crónica por un mes. Se realizaron observaciones cada diez días que demostraron los cambios que se producen en la presión arterial, los volúmenes y componentes de la orina: disminución de la, aumento del potasio plasmático, aumento de la calicreína urinaria y marcado efecto poliúrico durante todo el tratamiento, con marcado aumento de la excreción total de sodio y potasio urinarios