Aportes de la biotecnología al diagnóstico y tratamiento de la enfermedad renal crónica y comorbilidades frecuentes / Biotechnology contribution to the diagnosis and treatment of chronic kidney disease and frequent comorbidities

Este trabajo tiene como objetivo revisar las contribuciones de la biotecnología, en relación con el tratamiento, diagnóstico y la monitorización de la enfermedad renal crónica (ERC) y sus comorbilidades más frecuentes, especialmente la anemia. En relación con los tratamientos, enfocamos el desarrollo de productos biofarmacéuticos como los agentes estimulantes de la eritropoyesis (ESA), que fueron los primeros biofármacos utilizados para el tratamiento de la anemia asociada a la ERC; analizamos sus características y utilización actual después de varios años de experiencia clínica, así como también otras alternativas en desarrollo. Revisamos distintos tipos de bioterapias, la utilización de las células estromales mesenquimales de médula ósea (MSC) y tratamientos alternativos con modificaciones dietarias, que se basan en la asociación entre la microbiota intestinal de los pacientes renales crónicos y sus condiciones fisiopatológicas. Finalmente, en relación con el diagnóstico y monitorización, nos referimos al estudio y validación de biomarcadores diagnósticos, predictivos y terapéuticos que han permitido optimizar los resultados clínicos en este tipo de pacientes. (AU)

The aim of this work is to review the contributions of biotechnology, in relation to the treatment, diagnosis and monitoring of chronic kidney disease (CKD) and its most frequent comorbidities, especially anemia. Regarding the treatment, we focus on the development of biopharmaceutical products such as erythropoiesis stimulating agents (ESA), which were the first biopharmaceuticals used to treat anemia associated with chronic kidney disease (CKD). We analyzed their characteristics and their current use after several years of clinical experience, as well as other alternatives in development. We also review different types of biotherapies, the use of bone marrow mesenchymal stromal cells (MSC) and alternative treatments with dietary modifications, which are based on the association between the intestinal microbiota of chronic kidney patients and their pathophysiological conditions. Finally, in relation to diagnosis and monitoring, we refer to the study and validation of diagnostic, predictive and therapeutic biomarkers that have made clinical results possible to be optimized in this type of patient. (AU)

Epoetin alfa resistance in hemodialysis patients with chronic kidney disease: a longitudinal study

Anemia is an inevitable complication of hemodialysis, and the primary cause is erythropoietin deficiency. After diagnosis, treatment begins with an erythropoiesis-stimulating agent (ESA). However, some patients remain anemic even after receiving this medication. This study aimed to investigate the factors associated with resistance to recombinant human erythropoietin therapy with epoetin alfa (αEPO). We performed a prospective, longitudinal study of hemodialysis patients receiving treatment with αEPO at our reference hospital from July 2015 to June 2016. Clinical data was collected, and the response to αEPO treatment was evaluated using the erythropoietin resistance index (ERI). The ERI was defined as the weekly weight-adjusted αEPO dose (U/kg per week)/hemoglobin level (g/dL). A longitudinal linear regression model was fitted with random effects to verify the relationships between clinical and laboratory data and ERI. We enrolled 99 patients (average age, 45.7 (±17.6) years; male, 51.5%; 86.8% with hypertension). The ERI showed a significant positive association with serum ferritin and C-reactive protein, percentage interdialytic weight gain, and continuous usage of angiotensin receptor blocker (ARB) hypertension medication. The ERI was negatively associated with serum iron and albumin, age, urea reduction ratio, and body mass index. Our findings indicate that resistance to αEPO was related to a low serum iron reserve, an inflammatory state, poor nutritional status, and continuous usage of ARBs.

Effects of early human recombinant erythropoietin therapy on the transfusion in healthy preterm infants.

OBJECTIVE: Early recombinant erythropoietin therapy and iron therapy would decrease the need for red blood cells transfusions and prevents anemia of prematurity. METHODS: Fifty-eight preterm infants in newborn services at Ghaem Medical Center randomly were assigned, among them 18 patients were excluded. A total of 40 preterm infants with gestational age 28-34 weeks, birth weight 1000-1750 g followed the study: 20 infants in treatment group and 20 infants in control group were randomized to treatment (rhu EPO, 500u per kg, per week, 2 times weekly, subcutaneous) and control (no treatment). Therapy was initiated 4 days after birth and continued throughout the 4 weeks. All infants on enteral feeds received supplements: iron 3 mg/kg/d, vitamins and folat. Complete blood cells and reticulocyte counts were measured weekly. Transfusions and phlebotomy data were recorded. Statistical significance was determined by chi-square test, student t test and Mann-Whitney. A P value of < 0.05 was considered statistically significant. RESULTS: The reticulocyte counts were higher in treated infants during the study (p: 0.009). Final hematocrits were higher in treated infants (p: 0.02).The volume of packed red blood cells transfusions mililiter per infant significantly reduced (p: 0.05), the average number of transfusion per infant was also lower for treated infant than control [2 (10 % )vs 8 (40%) respectively]. No adverse effects of EPO or supplemental iron occurred. CONCLUSION: The combination of early rhu EPO and iron as administered in the present study stimulated erythropoiesis and decreased red blood cells transfusion in premature infants who were 1000-1750 g at birth. The enrollments of the larger and healthier preterm infants, who are at lower risk for transfusion, are limitation of the present study.

Role of interleukin-3 and signaling pathways on beta-thalassemia/HbE erythroid progenitor cell in culture.

In order to study the role of the cytokine interleukin-3 (IL-3) and its signaling pathways in erythropoiesis of beta-thalassemia/HbE erythroid progenitor cells, CD34 positive cells were isolated from peripheral blood of patients and healthy subjects. After culturing the cells in the presence or absence of IL-3, cell viability was measured by trypan blue staining and apoptotic cells were analyzed by flow cytometry. After 7 days of culture the highest percent erythroid progenitor cell viability was obtained with cells from healthy subjects, while the lowest percentage was found in those from splenectomized beta-thalassemia/HbE. Viability of beta-thalassemia/HbE erythroid progenitor cells in the presence of IL-3 was higher than that of nonsupplemented cells. In addition, specific inhibitors of protein kinase C (Ro-318220), phospholipase C (U-73122) and Janus kinase 2 (AG-490) were used to investigate the involvement of signaling pathways in erythropoiesis. Percent apoptosis of erythroid progenitor cells from splenectomized beta-thalassemia/HbE subjects treated with RO-318220 was higher than those of nonsplenectomized beta-thalassemia/HbE and healthy subjects. Treatment with U-73122 resulted in enhanced percent apoptotic cells from normal and beta-thalassemia/HbE subjects. All these effects were independent of IL-3 treatment.

Angiotensin converting enzyme inhibitors impair recombinant human erythropoietin induced erythropoiesis in patients with chronic renal failure

To investigate the effects of angiotensin converting enzyme [ACE] inhibitors/angiotensin receptor blockers [ARBs] and other anti-hypertensive agents on recombinant human erythropoietin [rHuEPO] in chronic renal failure [CRF] patients. The present study was conducted at the Nephrology Department, Khan Research Laboratories Hospital and Quaid-i-Azam University, Islamabad, Pakistan during March 2004 to February 2005. One hundred patients, 55 males and 45 females [age range 13-78 years] were divided into 2 groups. Group-I patients received rHuEPO and ACE inhibitors/ARBs while Group-II patients received rHuEPO with other antihypertensives such as calcium channel blockers or beta-adrenergic receptor blockers. Monthly increment in hematocrit [HCT%] was monitored in both groups for 4 continuous months. One-way ANOVA on Dunn's, univariate and multivariate analyses were carried out to determine any significant improvement in erythropoiesis between the 2 treatment groups. Monthly increase in HCT% was significantly greater in the group that was treated with rHuEPO and antihypertensives other than ACE inhibitors/ARBs compared with that treated with ACE inhibitors/ARBs, an effect observed even at a higher dose of rHuEPO, and the patients were iron replete. The present data from our population confirms that ACE inhibitors/ARBs interfere with rHuEPO therapy for treatment of anemia in CRF. The ACE inhibitors/ARBs inhibit erythropoiesis induced by rHuEPO in CRF patients, therefore, simultaneous use of ACE inhibitors/ARBs and rHuEPO should be carried out with caution

Effects of Adjuvant Androgen on Anemia and Nutritional Parameters in Chronic Hemodialysis Patients Using Low-dose Recombinant Human Erythropoietin

BACKGROUND: Recombiant human erythropoietin (epoetin) has greatly contributed to improvement of the anemia of chronic renal failure patients on hemodialysis. However, the reduced erythropoietic effect to epoetin and its high cost have induced lots of supplementary treatments. Therefore, we performed a prospective study to evaluate the effects of adjuvant low-dose androgen therapy in patients using a lower-dose of epoetin than the commonly recommended dose on anemia and the nutritional parameters. METHODS: 17 patients of hemoglobin (Hgb) less than 9 g/dL even after being treated with 1,000 U epoetin subcutaneously (s.c.) 3 times per week on a stable status for more than 6 months, who were on hemodialysis at our institution were examined. They were injected with the same dose of epoetin s.c. and nandrolone decanoate 100 mg intramuscularly (i.m) weekly for another 6 months. Blood test was performed every month before therapy for 6 months and after therapy for 6 months and the mean values were reviewed for comparison. RESULTS: Hgb (7.75+/-0.9 vs 8.99+/-1.39 g/dL, p < 0.01) and hematocrit (Hct) (23.68+/-2.85 vs 26.66+/-3.91%, p < 0.01) were apparently changed before and after adjuvant therapy. Hgb and Hct, weekly dose of epoetin were not statistically different in 9 male patients before and after adjuvant therapy. The weekly dose of epoetin was not statistically different in 8 female patients, but Hgb and Hct (8.02+/-0.6 vs 9.72+/-1.31 g/dL, 24.54+/-1.7 vs 28.74+/-3.06%, p < 0.01) were statistically different before and after adjuvant therapy. In comparison between male and female groups, weekly doses of epoetin and nandrolone decanoate were significantly greater in the female group than the male group (epoetin; 50.66+/-6.23 vs 61.18+/-8.76 U/kg/week, nandrolone decanoate; 1.69+/-0.2 vs 2.04+/-0.29 mg/kg/week, p < 0.05). CONCLUSION: Our data show that the adjuvant androgen therapy is effective for the anemia of hemodialysis patients who did not recover from anemia even after being continuously treated with low-dose epoetin.

Therapeutic trial of effective erythropoietin suppression in children affected with beta-thalassemia major: a three-year follow-up

A Three-year follow up study was conducted on 45 regularly transfused beta-thalassemic children; 23 of them were also given captopril therapy [6.25-12.5mg b.i.d.]. The aim was to evaluate the efficacy of captopril in inducing more effective suppression of erythropoiesis. Twenty age and sex matched controls were included at the end of study. All thalassemics were evaluated for their blood pressure [BP], hemoglobin [Hb], blood urea, serum creatinine, alkaline phosphatase, alanine aminotransferase, reticulocytic index [RI], serum ferritin, serum erythropoietin [sEpo] and serum transferrin receptors [s Tfr]; at the start and at the end of the study. Results showed that subjects given captopril, after 3 years therapy, had lower sEpo, sTfr and RI [31, 9, and 1.41 versus 60 mU/ml, 16 microg/ml, 2.3 respectively]; less incidence of splenomegaly [39 versus 77%]; higher height velocity and weight values; compared to thalassemics without captopril therapy [P<0.05]. Captopril used in regularly transfused beta-thalassemics could induce better suppression of endogenous erythropoiesis with reasonable cost, fair compliance and no side effects

Recombinant human erythropoietin in anemia of prematurity.

OBJECTIVE: To evaluate safety and efficacy of recombinant human erythropoietin (r-HuEPO)in reducing the need for red cell transfusions in anemia of prematurity. METHODS: forty -two preterm infants (gestational age <32 weeks) were randomly assigned to a "treatment" group (r-HuEPO 400 units/kg every alternate day * 10 doses) or "no treatment" (control) group. All infants on enteral feeds received oral iron 3 mg/kg/day, graded up to 6 mg/kg/day. RESULTS: Higher reticulocyte counts in week 2 and 3 and higher hemoglobin levels in week 4 were noted after treatment with r-HuEPO. Despite stumulated erythropoiesis, the frequency of transfusions could not be reduced with r-HuEPO therapy.Overall, Phlebotomy losses, frequency and volume of redcell transfusions were significantly more in neonates with birthweight <1000 grams compared with those with birthweight >1000 grams (p<0.05). Associated side effects of r-HuEPO such as neutropenia,sepsis, hypertension or increased risk of late death did not occur. CONCLUSION:r-HuEPO therapy was safe without any side effects.Inability of r-HuEPO therapy to minimize red cell transfusions for anemia of prematurity may be explained by a relatively strict red-cell transfusion policy and the desired degree of treatment effect.

Effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF) on murine bone marrow and spleen erythropoiesis

100 mug/kg of recombinant human granulocyte colony - stimulating factor was injected twice daily into normal adult CF1 female mice for a period of 15 days. After that time was have observed a decrease (59)Fe marrow incorporation with a parallel increase in the spleen. During the first 9 days the marrow plus spleen erythroid cells number decreased to 60 percent of control approximately, but recovered thereafter and were not significantly different from normal values at 12 - 15 days. In addition, our studies demonstrate that the spleen erythropoiesis is quantitatively more important at the final time tham marrow erythropoiesis. For this reason, splenic compensatory erythropoiesis maintained the hematocrit values between normal ranges. Regarding the granulocytic compartment, 15 days of rhG-CSF treatment produce a marked increase in total count os splenic granulocytes (a 7.7 fold rise from control values). Marrow granulocytes shows a 2 - fold increment, but considering the absolute counts, bone marrow still was predominant as a granulopoieitc organ. Our results indicate that the spleen is a more important erythropoietic organ than marrow after 15 days of rhG-CSF treatment.

Blockade of the in vitro effects of testosterone and erythropoietin on Cfu-E and Bfu-E proliferation by pretreatment of the donor rats with cyproterone and flutamide

Erythropoietin is obligatory to support the terminal proliferation and differentiation of erythroid cells but it is not the only agent in modulating red cell production. Previously, we have shown that Testosterone enhances erythropoiesis, at least in part, by increasing renal erythropoietin production. Testosterone may also influence directly the behavior of the erythroid progenitor cells increasing erythroid stem cell proliferation. To gain further insight into the role of testosterone in regulation of erythropoiesis and its interactions with erythropoietin, we studied the effect of testosterone and erythropoietin, using clonal cultures of erythropietic progenitors, to observe CFU-E and late and early BFU-E colonies proliferation from bone marrow cells of donor rats pretreated for 2 days with the androgen antagonists cyproterone (10 mg/Kg/day) and flutamide (160 mg/Kg/day). Specific nuclear receptors for testosterone were demonstrated in marrow erythroid cells. Then, erythroid progenitors may come with their androgen receptors blocked by pretreatment. Cultures were prepared using the methylcellulose technique containing a standard dose of erythropoietin (250 mu/ml) or testosterone (10(-7) M). Results obtained demonstrate that testosterone produced a significant stimulation on CFU-E and BFU-E colony formation. A dose effect correlation was apparent. Testosterone enhances proliferation of late BFU-E more than CFU-E and produce only a slight augmentation of early BFU-E. As expected, erythropoietin markedly stimulate all erythroid colony growth, mainly CFU-E. The effects of testosterone were completely abolished in cultures from bone marrow cells of rats pretreated with cyproterone and flutamide. Activation of the specific androgen nuclear receptors in erythroid cells appears to be necessary for testosterone to develop the erythropoietic effect. Surprisingly, the effects of erythropoietin on erythroid colonies proliferation were also completely blocked by pretreatment with flutamide and partially blocked by pretreatment with cyproterone. Right now, we do not have a satisfactory explanation regarding inhibition of the effects of erythropoietin by pretreatment to marrow donor rats with the androgen antagonists. In conclusion, we postulate triggering late BFU-E cells, a marrow erythropoietin responsive cell population, into active cell cycle, as well as by increasing blood erythropoietin concentration.

Urinary elimination of erythropoietin in patients under treatment with cytostatics drugs

La reducción de la masa de hemoglobina (Hb) que ocurre en las anemias aumenta la producción de eritropoyetina (EPO) en una proporción conmensurada con el nivel de estímulo eritropoyético necesario para reponer la normalidad de la dimensión de la masa del pigmento transportador de oxigeno. Las anemias hipoplásticas congénitas (AHC) muestran niveles de Epo plasmática substancialmente mayores que las que se comprueban en anemias en las que no existe esa alteración medular. En este estudio hemos medido los niveles de Epo eliminada por orina (EpoU) en pacientes bajo tratamiento con drogas citostáticas (DC). Simultáneamente se determinaron otros parámetros hemáticos utilizados corrientemente como indicadores de la actividad medular. Nuestras observaciones sugieren que existen otros factores involucrados en la produccion de Epo además de la hipoxia tisular, los que estarían probablemente relacionados a la celularidad medular.

Erythropoietin requirement for the maintenance of normal levels of erythropoiesis in the normal adult mouse

Erythropoietin (EPO) is a glycoprotein which appears as the primary regulator of erythropoiesis under either normal or most of the pathologic conditions. In the rat with experimentally-reduced erythropoiesis, daily administration of 1.3 IRP units can restores the function and maintain steady-state conditions of red cell formation. This important information for the programming of both physiologic and pharmacologic studies is lacking for the mouse, in spite of the fact that most of the experiments performed on the regulation of erythropoiesis have been conducted in this species. In the present study, designed to determine EPO requirement for maintenance of steady-state erythropoiesis in the adult mouse under standard laboratory conditions, adult females of the CF#1 strain were exposed to hypobaria (18h/day) durring a 3-week period for induction of polycythemia (P). At the end of the hypoxic period, P mice were maintained at sea level conditions, as were normocythemic (N) mice during the entire experimental period. P mice were daily injected with 0,0.5, 1.0, 1.5, or 2.0 IRP units of rHu-EPO during the 4-day period that followed the hypoxic one. The rate of erythropoiesis in N and P mice were measured by RBC(-59) Fe uptake. The plasma (59)Fe half-clearance time was also measured in other groups of N and P mice similarly treated. One-way ANOVA showed that the only non-significant difference (P>0.05) between N and EPO-injected P mice was established for the 1.0 unit dose group. It is thus suggested that approximately 1.0 unit of EPO should be synthesized aily in an adult mice to maintain a normal rate of erythropoiesis.

Unmodified erythropoietic response to a beta adrenergic agonist in hypothyroid mice

Los agonistas beta-adrenérgicos poseen la propriedad de estimular la eritropoyesis en el modelo del ratón policitémico mediante inducción de la secreción de eritropoyetina. Considerando la existencia de un cúmulo de evidencias que indica que las hormonas tiroideas y las catecolaminas están íntimamente relacionadas, el objetivo del presente trabajo fue estimar la potencia eritropoyética del isoproterenol, un agonista beta-adrenérgico bien conocido, en ratones hipotiroideos. Animales adultos de la cepa CF-1 fueron alimentados con dieta estandard para roedores y agua (eutiroideos) o solución al 0.1 por ciento de propiltiouracilo durante 37 dÝas. La concentración de T4 en plasma, medida por RIA, fue 1.75 mug/ml y < 1.0 mug/ml en ratones eutiroideos e hipotiroideos, respectivamente. Los animales fueron transfundidos con 1.0 ml de eritrocitos homólogos y el efecto eritropoyético de 50, 500 o 5000 pg/kg de isoproterenol estimado mediante el método de incorporación de (59)Fe al eritrón. No se observaron diferencias estadísticamente significativas (P<0.05, test de t no apareado) entre animales eutiroideos e hipotiroideos. El hipotiroidismo, por lo tanto, no afecta la secreción de eritropoyetina inducida por isoproterenol en las presentes condiciones experimentales.

Sodium cyanate: from a promising therapeutic agent to a research tool in high altitude physiology

Sodium cyanate (NaOCN) first appeared on the biomedical scene as a potential therapeutic agent for sickle-cell disease. Although it did not fulfill its early promise in the clinic, it proved to be useful as a pharmacological tool in physiological research, particularly in the physiology of oxygen transport. NaOCN has been especially valuable in the area of investigation which is reviewed here: the study of oxygen transport, both in normoxic and in hypoxic conditions, in experimental models in which NaOCN was used to induce a shift to the left of the oxygen dissociation curve. The classical idea is that a low Hb-O2 affinity is of adaptive value for life at high altitudes but it has been challenged by several pieces of evidence. One of them is the demonstration of increased survival in hypoxic hypoxia of animals with a high Hb-O2 affinity induced by NaOCN. We also discuss the advantages and potentially confounding factors which should be taken into consideration when interpreting results of studies in which the oxygen dissociation curve has been modified by administration of NaOCN

Enhancement of erythroid colony growth by triiodothyronine in cell cultures from bone marrow of normal and anemic rats with chronic renal failure

Para contribuir a clarificar el rol de las hormonas tiroideas en la modulación de la eritropoyesis y profundizar en el conocimiento de los efectos de estas hormonas en la anemia de la insuficiencia renal crónica (CRF), estudiamos "in vitro" la acción de la l-triiodotironina (LT) y DT3, un isómero dextrorotatorio no-calorigénico de la T3 sobre precursores eritroides comprometidos maduros (CFU-E) y primitivos (BFU-E) de la médula ósea de ratas normales anémicas. Los cultivos fueron preparados usando la técnica de la metilcelulosa conteniendo una dosis standard de eritropoyetina (Ep) (182 mU/ml), LT3 y DT3 en dosis de o.5, y 1.5 ug/ml. Las hormonas tiroideas fueron agregadas a los cultivos en ausensia de Ep. Nuestros resultados demuestram que LT3 y DT3 producen una estimulación significativa y directa sobre la formación de CFU-E y un moderado incremento de BFU-E. Hubo una aparente relación dosis-dependiente en los cultivos que contienen las hormonas tiroideas. La DT3 fue menos activa que la LT3. Como se esperaba, la Ep produjo un significativo incremento en la formación de colonias eritroides, principalmente CFU-E. Los efectos de LT3, DT3 y Ep sobre el desarrollo de las colonias eritroides fue significativamente mayor en cultivos celulares de médula ósea de ratas anémicas con CRF, indicando la existencia de una cinética celular proliferativa más elevada en los progenitores eritroides comprometidos en respuesta a estas drogas.

Tratamiento de niños con insuficiencia renal crónica terminal con eritropoyetina recombinante humana / Treatment with recombinant human erythropoietin (rHuEPO) of children with terminal chronic renal failure (TRF)

Con el propósito de evaluar los efectos de la eritropoyetina recombinante humana (EPOrHu) sobre la anemia en niños con insuficiencia renal crónica terminal (I.R.C.T.), 10 pacientes con edad promedio de 10,55 +/- 5,20 años (rango: 3 a 16), todos en diálisis peritoneal ambulatoria continua (D.P.A.C.), recibieron tratamiento durante 16 semanas. Previo a la terapia, presentaban: hemoglobina: promedio 6,08 +/- 0,41 (rango 5,5 a 6,6) g/dl, hematócrito: promedio 18,4 +/- 2,01 por ciento (rango: 15 a 21). La dosis inicial de EPOrHu fue de 25 unidades/kg peso, administrada por vía subcutánea, ajustándola según el incremento porcentual del hematócrito y fijándose como objetivo un hematócrito de 30 por ciento. La respuesta al tratamiento se valoró a través del incremento de los valores de hemoglobina y hematócrito, analizándose estadísticamente los resultados por t de Student. Previo a la terapia, y periódicamente, se determinó hierro sérico, ferritina, creatinina y recuento de reticulocitos. Al final de la terapia se obtuvo una hemoglobina promedio de 8,08 +/- 1,18 g/dl (p < 0,001) y un hematócrito promedio de 24,9 +/- 4,33 por ciento (rango 17-30) (p < 0,001). La hipertensión arterial fue el efecto adverso más comúnmente observado. Se concluye que la EPOrHu constituye una terapia efectiva para coregir de manera importante la anemia en niños con I.R.C.T., para evitar el uso de transfusiones sanguíneas y mejorar la calidad de vida de los pacientes. El control adecuado de la tensión arterial preterapia y el ajuste de la medicación hipotensora obvia este efecto adverso

Late afternoon administration of melatonin is prosomatotrophic and exerts androgen independent effects on erythropoiesis in male house sparrow Passer domesticus.

In the third week of September 1989, birds were purchased locally and acclimated to their housing conditions in a room fully exposed to natural day length (average: 11.96 hr) and temperature (26 degrees +/- 2 degrees C) for 2 weeks. Birds were in the regressive phase of their annual gonadal cycle. In the first experiment 24 birds were selected randomly and were divided into 3 groups of 8 birds each. Initial body weight and bill color score were recorded. The birds of group-I and group-II were injected daily with 5 and 10 micrograms of melatonin in 0.1 ml of vehicle, respectively. The birds of group-III were injected with vehicle only and treated as control. Injections were given daily between 1700 and 1730 hrs over a period of 10 days. At the termination of the experiment, the birds were weighed, sacrificed, bill color scored, blood collected and immediately processed to determine the number of erythrocytes and hemoglobin concentration. The mean body weight loss amounted to 9.6% in vehicle-treated house sparrow. Birds receiving low and high doses of melatonin maintained their initial body weight. Melatonin significantly accelerated the rate of bleaching of bill color. Results clearly indicate that in house sparrow, melatonin produces prosomatotrophic and antigonadotrophic effects. The low dose of melatonin stimulated erythropoiesis significantly. In the second experiment, melatonin nullified the castration-induced decline in the number of circulating red cells. This clearly suggests that the influence of melatonin on erythropoietic machinery appears to be independent of testicular hormone(s).