RESUMEN
The objective of this study was to examine testicular ultrasonographic characteristics and endocrine profiles in prepubescent ram lambs for correlations with the age at first detection of elongated spermatids (ESt age). Bi-weekly ultrasound examinations and weekly testicular biopsies began at 10 weeks of age or at the time that testicular volume reached 15cm3, and continued until 1-2 weeks after Est's were first detected by histological examination of testicular biopsies in twenty-two spring-born Rideau Arcott×Polled Dorset lambs. Computer-assisted analysis of testicular ultrasonograms was performed using commercially available image analytical software. Blood samples were drawn before each ultrasonographic examination and were used for measurements of free triiodothyronine (fT3) and thyroxine (fT4), and follicle-stimulating hormone (FSH) concentrations. The mean (±SEM) age at first detection of ESts was 15.9±0.5 weeks. Testicular volumes recorded between 10 and 12 weeks of age correlated inversely with the ESt age (r=-0.44 to -0.50, P≤0.05). Statistically significant correlations were recorded between the ESt age and numerical pixel values of testicular parenchyma at 10 (r=-0.48, P=0.05) and 15 (r=0.52, P=0.05) weeks of age, and between the ESt age and testicular pixel heterogeneity in ram lambs aged 14.5 weeks (r=0.60, P=0.007). Lastly, circulating FSH concentrations at 10 weeks (r=-0.43, P=0.05), serum fT3 concentrations at 13 weeks (r=0.44, P=0.04) and fT4 concentrations at 11.5 weeks of age (r=0.48, P=0.03) were all correlated with the ESt age. The present results show that testicular volume has the most stable relationship with pubertal onset; however, testicular echotexture as well as circulating concentrations of FSH and free fractions of thyroid hormones at specific ages may be indicative of more intricate developmental events heralding puberty.
Asunto(s)
Maduración Sexual/fisiología , Ovinos/fisiología , Espermatogénesis/fisiología , Testículo/diagnóstico por imagen , Ultrasonografía/veterinaria , Envejecimiento , Animales , Hormona Folículo Estimulante/sangre , Masculino , Sensibilidad y Especificidad , Ovinos/sangre , Tiroxina/sangre , Triyodotironina/sangreRESUMEN
Testicular echotextural attributes are closely associated with spermatogenic development; however, precise characterisation of specific germ cell types is difficult due to tremendous germ cell heterogeneity. Recently, retinoic acid (RA) administration in neonatal mice was found to induce highly synchronised spermatogenesis as adults. A RA-treatment protocol was tested in 17 ram lambs treated with or without RA at 8 weeks of age, with scrotal ultrasonography and blood samples collected until castration 24h or 2.5 weeks later. At 8.2 weeks of age, the nuclear:seminiferous tubule (ST) area was higher in the treated compared with the control group. Serum testosterone concentrations and numerical pixel values (NPVs) of the testicular parenchyma reached a peak at 9 weeks of age in both groups of ram lambs studied. At 10.5 weeks of age, the percentage of ST cross-sections with different germ cells as the most mature germ cell type was lower and the inter-tubular heterogeneity and NPVs were also lower in the treated compared with the control animals. RA manipulation of spermatogenesis in prepubertal ram lambs may provide a suitable model for further investigation of the echotextural characteristics of specific germ cell types and critical developmental events.
Asunto(s)
Células Germinativas/efectos de los fármacos , Testículo/efectos de los fármacos , Testosterona/sangre , Tretinoina/farmacología , Animales , Estradiol/sangre , Hormona Folículo Estimulante/sangre , Masculino , Túbulos Seminíferos/diagnóstico por imagen , Túbulos Seminíferos/efectos de los fármacos , Ovinos , Testículo/diagnóstico por imagen , UltrasonografíaRESUMEN
BACKGROUND: It is well established that spontaneous conceptus loss in swine is associated with an imbalance of both angiogenic and immunological factors. Leptin (LEP), a metabolic hormone, has also been implicated in the promotion of angiogenesis. In this study, LEP and its long form receptor (OB-Rb) were evaluated during porcine pregnancy to assess their basal level of expression and their potential role in conceptus development. METHODS: Expression and secretion of LEP and OB-Rb were quantified in the endometrium of non-pregnant (n = 5), and in the endometrium and chorioallantoic membrane (CAM) of pregnant sows (parity 2 to 5) at gestational days (gd) 20 (n = 8) and 50 (n = 8). Data were analyzed by a 3-way ANOVA testing the effects of conceptus health, tissue type and gestational day. RESULTS: Leptin and OB-Rb transcripts were significantly higher (P < 0.05) in pregnant than in non-pregnant sows. Significantly greater LEP (P < 0.001) was detected in the endometrial tissue at gd20 compared with gd50. At the protein level, the lowest LEP expression (P < 0.01) was detected in the CAM at gd50, while OB-Rb protein was significantly lower (P < 0.01) at gd50 in the CAM than in the endometrium collected from gd20 and gd50 conceptus attachment sites. Immunofluorescence staining confirmed the expression of these proteins at both gestational days and in both tissue types. CONCLUSIONS: Changes in the expression patterns of LEP and OB-Rb between gd20 and gd50 suggest a role for the LEP/OB-R complex at the early stages of porcine pregnancy, possibly affecting the attachment process. Further mechanistic studies are warranted to understand the specific role of leptin in porcine pregnancy.
Asunto(s)
Membrana Corioalantoides/metabolismo , Endometrio/metabolismo , Regulación del Desarrollo de la Expresión Génica , Leptina/metabolismo , Precursores de Proteínas/metabolismo , Receptores de Leptina/metabolismo , Sus scrofa/fisiología , Animales , Animales Endogámicos , Membrana Corioalantoides/citología , Membrana Corioalantoides/embriología , Endometrio/citología , Femenino , Desarrollo Fetal , Técnica del Anticuerpo Fluorescente/veterinaria , Inseminación Artificial/veterinaria , Leptina/genética , Ontario , Placentación , Embarazo , Mantenimiento del Embarazo , Precursores de Proteínas/genética , ARN Mensajero/metabolismo , Receptores de Leptina/genética , Organismos Libres de Patógenos EspecíficosRESUMEN
The onset of spermatogenesis during prepubertal development is accompanied by dynamic changes in testicular microstructure. Computer-assisted analysis of scrotal ultrasonograms may allow us to track these changes in a noninvasive manner; however, the echotextural characteristics of different histomorphological variables remain unclear. Hence the objective of this study was to compare echotextural and microscopic attributes of the testis over the first wave of spermatogenesis in prepubescent ram lambs. Bi-weekly ultrasound examinations and weekly testicular biopsies were carried out in 22 ram lambs from 9.5-10 weeks of age or the attainment of 15 cm(3) in testicular volume, respectively, to the first detection of elongated spermatids (ESt). Testicular echogenicity was highly variable with age; however, after the alignment of data to the first detection of ESt, there was an initial increase followed by a decline, corresponding to the mitotic and postmitotic phases of spermatogenesis in prepubescent ram lambs. Testicular echotextural attributes (mean numerical pixel values and pixel heterogeneity) correlated with seminiferous tubule (ST) diameter, the number of degenerating cells/ST cross-section (XS), and the number of ubiquitin C-terminal hydrolase L-1 (a marker for prespermatogonia and undifferentiated spermatogonia) staining cells/ST XS during the mitotic and postmitotic phases. Additionally, in the postmitotic phase, significant correlations were recorded between the quantitative echotextural characteristics and ST cell density, nuclear:ST area and percentages of STs with different spermatogenic cells as the most mature germ cell type present. These results indicate that ram testes exhibit distinctive echotextural characteristics during the mitotic and postmitotic phases of germ cell differentiation. It is concluded that scrotal ultrasonography in conjunction with computerized image analysis holds potential as a noninvasive alternative to testicular biopsy in monitoring the reproductive status throughout different stages of testicular development.
Asunto(s)
Histocitoquímica , Microscopía , Maduración Sexual , Ovinos/anatomía & histología , Testículo/anatomía & histología , Testículo/diagnóstico por imagen , Animales , Biopsia , Procesamiento de Imagen Asistido por Computador , Masculino , Ovinos/fisiología , Espermatogénesis , Testículo/fisiología , UltrasonografíaRESUMEN
The main purpose of this study was to determine if temporal relationships exist between serum concentrations of free fractions of thyroxin (fT4) and triiodothyronine (fT3), follicle-stimulating hormone (FSH) levels, and Sertoli cell differentiation in euthyroid ram lamb testes. Additionally, testicular thyroid hormone (TH) receptors (TRs) were identified using immunohistochemistry and Western blot analysis. Weekly testicular biopsies and jugular blood samples were collected from 12 ram lambs over the 9 weeks of study. Hormone concentrations and the numbers of dividing Sertoli cells per seminiferous tubule (ST) area were analyzed relative to chronological age of animals and the two distinctive stages of Sertoli cell differentiation: (a) tight junction/ST lumen formation and (b) the onset of support mechanisms for the development of multiple germ cell types (presence of primary spermatocytes in >95% STs). Circulating FSH concentrations increased (p<0.05) immediately after first detection of ST lumen and reached a nadir (p<0.05) just prior to the end of the first wave of spermatogenesis. A decline in both fT4 and fT3 levels (p<0.05) occurred after Sertoli cells had formed the ST lumen and began supporting germ cell differentiation. There was a positive correlation between the numbers of proliferating Sertoli cells and serum fT4 (r=0.51, p<0.001) and fT3 (r=0.52, p<0.001) concentrations. TRs were expressed throughout the study period; however, prior to the formation of ST lumen, two isoforms were detected while only one TR isoform was present by the end of the first wave of spermatogenesis. Overall, the exit of Sertoli cells from the cell cycle that presages their final differentiation begins when THs and FSH levels are high, suggesting a permissive role of these hormones in the maturation of STs in prepubertal ram lambs.
Asunto(s)
Diferenciación Celular/fisiología , Hormona Folículo Estimulante/sangre , Túbulos Seminíferos/citología , Células de Sertoli/citología , Ovinos/fisiología , Espermatogénesis/fisiología , Hormonas Tiroideas/sangre , Análisis de Varianza , Animales , Western Blotting/veterinaria , Procesamiento de Imagen Asistido por Computador , Inmunohistoquímica/veterinaria , Masculino , Radioinmunoensayo/veterinaria , Receptores de Hormona Tiroidea/metabolismo , Túbulos Seminíferos/metabolismo , Ovinos/metabolismoRESUMEN
Declining male fertility has prompted investigations into the diagnostic methods that would permit frequent, non-invasive and accurate detection of changes in testicular histomorphology and the reproductive status of individuals. Ultrasonographic (U/S) and magnetic resonance (MR) imaging both have the potential to be used in this manner as associations have previously been described between the U/S and MR image attributes and histopathological changes in testicular tissue. The present study set out to determine if correlations exist between quantitative U/S and MR image attributes and histomorphological characteristics (total and luminal seminiferous tubule, ST area, and parenchymal cell density) of the excised ram testes, and to compare relative sensitivities of the imaging techniques. The echotextural/MR (input variables) and histological parameters (output variables) were analyzed by the Pearson's product moment correlations. Significant correlations were found for all imaging modalities, with the strongest overall correlation recorded for the T2 FAST SPIN ECHO (T2FSE) MR series (between mean numerical pixel values (NPVs) and total ST area; r=-0.93, p<0.001). The greatest number of significant correlations among quantitative image characteristics and histological attributes of testicular tissue were found for the 3 PLANE LOCALIZER (3 PLANE LOC) MR series, followed by the T2FSE MR, 3D FAST-SPOILED GRADIENT ECHO (3D FSPGRE) MR, U/S (7.5 MHz) imaging, and finally T1 SPIN ECHO (T1SE) MR series. No significant correlations were recorded between the quantitative attributes of T1SE images and ST lumen area or parenchymal cell density, or between the attributes of the 3D FSPGRE images and cell density. We concluded that there existed a potential practical application for both U/S and MR image techniques, combined with computer-assisted image analysis, to monitor the changes in testicular histomorphology and male reproductive health and fertility. Scrotal U/S remains a first-line imaging technique for the assessment of male reproductive health due mainly to its versatility and lower cost.
Asunto(s)
Imagen por Resonancia Magnética/veterinaria , Ovinos/anatomía & histología , Testículo/diagnóstico por imagen , Testículo/ultraestructura , Ultrasonografía/veterinaria , Animales , Imagen por Resonancia Magnética/métodos , Masculino , Radiografía , Ultrasonografía/métodosRESUMEN
Breeding soundness evaluation (BSE) is the primary assessment for determining the reproductive potential of male animals. This method, however, cannot be used to evaluate semen frequently or to predict future semen quality. Computerized analysis of ultrasonographic images provides information on histophysiological changes in male reproductive organs. We hypothesized that: (i) semen parameters would correlate with ultrasonographic characteristics of the distal region (cauda) of the epididymis and (ii) testicular ultrasound images and/or circulating testosterone concentration would predict future semen quality in the ram. Six adult rams underwent BSE and scrotal ultrasonography approximately 60 d apart (average duration of the spermatogenic cycle) both during the breeding (December and February) and non-breeding (June and August) seasons. An inverse correlation was found between pixel intensity (numerical pixel values) of the epididymes and percentage of sperm in semen with normal morphology (r = -0.46, P < 0.05). Pixel heterogeneity (standard deviation of pixel values) correlated negatively with percentage of sperm with normal morphology (r = -0.42, P < 0.05) and directly with percentage of spermatozoa with abnormal tails (r = 0.43, P < 0.05). Pixel heterogeneity of testicular parenchyma obtained approximately 60 d prior to semen evaluation inversely correlated with percentage of sperm with normal morphology (r = -0.73, P < 0.01) and sperm progressive motility (r = -0.76, P < 0.01), and directly with percentage of sperm with abnormal tails (r = 0.72, P < 0.01) and loose heads (r = 0.79, P < 0.01). We concluded that scrotal ultrasonography combined with computer-assisted analyses of epididymal and testicular echotexture in the ram was a valuable method for determining certain current and future semen parameters, respectively.
Asunto(s)
Epidídimo/diagnóstico por imagen , Procesamiento de Imagen Asistido por Computador/métodos , Testículo/diagnóstico por imagen , Ultrasonografía/métodos , Animales , Humanos , Masculino , Oncología Médica/métodos , Análisis de Regresión , Semen/fisiología , Análisis de Semen , Ovinos , Recuento de Espermatozoides , Motilidad Espermática , Testículo/patologíaRESUMEN
Xenografting of testicular tissue is an attractive new strategy for studying postnatal development of spermatogenesis and to preserve male genetics in large mammals. Typically, small cubes of immature testis (1 mm(3)) are grafted under the dorsal skin of immune-deficient mice. We attempted to increase the total number of seminiferous tubules in each xenograft with spermatogenesis by grafting flat strips of testis (approximately 9 x 5 x 1 mm) from ram lambs in immune-deficient mice. The percentage of grafts that survived and percentage of seminiferous tubules that developed spermatogenesis were the same as those reported after xenografting small cubes of lamb testis. Partially purified sheep spermatogonia were labeled with the fluorescent dye carboxy fluorescein diacetate succinyl diester and transplanted into the seminiferous tubules of one of the donor testis just before engraftment. The temporary label in the donor cells was detected for 4 weeks after xenografting, suggesting that co-engraftment of spermatogonia with testicular tissue may be a way to rapidly determine the effect of a specific gene on spermatogenesis. Finally, Sertoli cell lesions in xenografts of lamb testes were quantified, and their number and severity were found to increase, especially after grafts had been in place for 4 weeks. Although this coincided with the development of spermatogenesis, the extent of germ cell differentiation negatively correlated with severity of the lesions.
Asunto(s)
Espermatogénesis , Espermatogonias/trasplante , Testículo/trasplante , Trasplante Heterólogo/métodos , Animales , Funcionamiento Retardado del Injerto/patología , Colorantes Fluorescentes , Técnicas Genéticas , Supervivencia de Injerto , Huésped Inmunocomprometido , Masculino , Ratones , Epitelio Seminífero/citología , Epitelio Seminífero/patología , Epitelio Seminífero/fisiología , Túbulos Seminíferos/citología , Túbulos Seminíferos/patología , Túbulos Seminíferos/fisiología , Células de Sertoli/citología , Células de Sertoli/patología , Oveja Doméstica , Espermatogonias/patología , Espermatozoides/citología , Espermatozoides/patología , Testículo/citología , Testículo/patología , Factores de Tiempo , Trasplante Heterólogo/inmunología , Vacuolas/ultraestructuraRESUMEN
The ultrasonographic image of an organ is a product of scattering and reflection of high-frequency ultrasound beams by discrete units of tissue. The number of acoustic tissue interfaces and vascularity affects the quantitative characteristics of grey-scale ultrasonographic images. This study was undertaken to examine the influences of scrotal/testicular integument and blood flow on testicular echotexture parameters in the ram. Serial ultrasonographic images were obtained during surgical castration of 7 Rideau Arcott rams aged 20-22 weeks. The first 2 sets of images were taken through the scrotum, prior to and after induction of anaesthesia. The third set was taken through the tunica vaginalis, the fourth set was obtained through the tunica albuginea, the fifth set was taken when the testicular cord and internal blood vessels were clamped, and the final set of images was recorded after allowing the blood to drain from dissected testicles (5 min). All images were then subjected to computerized image analyses and the testicles were processed for histology. The removal of the scrotal skin and tunica vaginalis both resulted in significant (P < 0.05) increments in numerical pixel values (NPVs) and pixel heterogeneity (standard deviation of pixel values) of the testicular parenchyma. There were no differences (P > 0.05) in testicular echotexture between images taken just before or after clamping the testicular cord vessels, or after draining. At all stages, NPVs were correlated (P
Asunto(s)
Testículo/irrigación sanguínea , Testículo/diagnóstico por imagen , Animales , Procesamiento de Imagen Asistido por Computador , Masculino , Flujo Sanguíneo Regional/fisiología , Análisis de Regresión , Escroto/irrigación sanguínea , Escroto/diagnóstico por imagen , Ovinos , UltrasonografíaRESUMEN
Studies in rodents show that spermatogonial transplantation is an excellent new tool for studying spermatogenesis and for preservation and dissemination of genetics. The aim of this study was to adapt the technique to rams. Two issues were addressed: purification of stem cell spermatogonia, and efficient injection of donor spermatogonia into the seminiferous tubules of rams. We compared differential plating and Percoll gradient methods for purifying donor spermatogonia from ram lamb testes. Spermatogonia were identified with an antibody against PGP 9.5, a ubiquitin C-terminal hydrolase. Both purity and total number of spermatogonia recovered were higher after purification by Percoll gradient than by differential plating. Four approaches for injecting cells into the seminiferous tubules of ram testes were compared ex vivo: insertion of a needle into the extra-testicular rete testis after reflection of the head of the epididymis ('surgical' approach), and ultrasound-guided insertion of a needle into the extra-testicular rete, and the proximal and distal parts of the intra-testicular rete testis. 'Surgical' and ultrasound-guided approaches into the extra-testicular rete resulted in highest success rates and best filling of the seminiferous tubules. Finally, the ultrasound guided approach into the extra-testicular rete testis was validated in vivo by transplanting purified spermatogonia previously labeled with a fluorescent molecule (CFDA-SE). In seven of eight testes injected, donor cells were identified within the seminiferous epithelium for up to 2wk after transplantation, indicating the integration of donor cells.
Asunto(s)
Ovinos/fisiología , Espermatogénesis/fisiología , Espermatogonias/trasplante , Testículo/citología , Animales , Animales Recién Nacidos , Inmunohistoquímica/veterinaria , Masculino , Microinyecciones/veterinaria , Túbulos Seminíferos/citología , Túbulos Seminíferos/fisiologíaRESUMEN
Real time RT-PCR was used to measure the changes in the rates of synthesis of mRNA encoding for growth hormone-1 (GH1) and -2 (GH2) and insulin-like growth factor-1 (IGF-1) and -2 (IGF-2), and whole embryo GH content was measured in early stage rainbow trout (Oncorhynchus mykiss) embryos reared at two incubation temperatures (8.5 and 6.0 degrees C). Particular attention was paid to the phase of embryo development that preceded the appearance of the pituitary gland. GH was present in zygotes, and there were no significant changes in whole embryo GH content of the two temperature treatment groups from fertilization (t0) until the time at which GH was detectable in the pituitary gland by immunostaining. The expression of the two GH genes decreased during the first 24 h post-fertilization, and then increased significantly by 17 dpf in embryos reared at both temperatures. There was a subsequent steep increase in the number of copies of GH1 and GH2 mRNA associated with the formation of the pituitary gland evident at 23 and 34 dpf in the 8.5 and 6.0 degrees C groups, respectively. The number of copies of mRNA encoding for IGF-1 and IGF-2 did not change during the first 24 h post-fertilization; however, there was a significant increase in the numbers of transcripts for both genes evident by 13 dpf in embryos reared at the two incubation temperatures. The differences in the timing of the increases in GH and IGF mRNA may suggest that IGF gene expression is not GH-dependent at that stage. Moreover, the increased expression of the GH genes prior to the formation of the pituitary gland suggests that tissues other than the pituitary are expressing these genes in early embryos. The pattern of changes in GH content was similar to the pattern of GH gene expression in embryos reared at the two incubation temperatures when the age of embryos was plotted using degree-days. There were no apparent compensatory responses in GH1, GH2, IGF-1 or IGF-2 gene expression related to altered growth rates. The number of copies of IGF-2 mRNA was higher than that of IGF-1 mRNA during the early developmental period; this is consistent with the hypothesis that IGF-2 predominates during embryonic development. A differential expression of GH2 and GH1 was also observed with the overall copy numbers of GH2 mRNA being consistently higher than those of GH1.
Asunto(s)
Hormona del Crecimiento/genética , Factor II del Crecimiento Similar a la Insulina/genética , Factor I del Crecimiento Similar a la Insulina/genética , Oncorhynchus mykiss/embriología , Hipófisis/embriología , Animales , Embrión no Mamífero , Proteínas de Peces/genética , Regulación del Desarrollo de la Expresión Génica , Hormona del Crecimiento/metabolismo , Oncorhynchus mykiss/genética , Isoformas de Proteínas/genética , ARN Mensajero/análisis , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , TemperaturaRESUMEN
In the preimplantation mouse embryo, the protein kinase C (PKC) family has been implicated in regulation of egg activation, progression of meiotic and mitotic cell cycles, embryo compaction, and blastulation, but the involvement of the individual isozymes is largely unknown. Here, using semiquantitative immunocytochemistry and confocal microscopy we analyze the relative amount and subcellular distribution of ten isozymes of PKC (alpha, betaI, betaII, gamma, delta, epsilon, eta, theta, zeta, iota/lambda) and a PKC-anchoring protein, receptor for activated C-kinase 1 (RACK1). Our results show that all of these isoforms of PKC are present between the two-cell and blastocyst stages of mouse preimplantation development, and that each has a distinct, dynamic pattern and level of expression. The data suggest that different complements of the isozymes are involved in various steps of preimplantation development, and will serve as a framework for further functional studies of the individual isozymes. In particular, there was a transient increase in the nuclear concentration of several isozymes at the early four-cell stage, suggesting that some of the PKC isozymes might be involved in regulation of nuclear organization and function in the early mouse embryo.
Asunto(s)
Blastocisto/enzimología , Desarrollo Embrionario/fisiología , Isoenzimas/análisis , Proteína Quinasa C/análisis , Animales , Núcleo Celular/enzimología , Citoplasma/enzimología , Femenino , Inmunohistoquímica/métodos , Isoenzimas/metabolismo , Ratones , Microscopía Confocal , Mórula/enzimología , Embarazo , Proteína Quinasa C/metabolismoRESUMEN
During mouse preimplantation development, two isozymes of protein kinase C (PKC), delta and epsilon, transiently localize to nuclei at the early four-cell stage. In order to study their functions at this stage, we altered the subcellular localization of these isozymes (ratio of nuclear to cytoplasmic concentrations) with peptides that specifically activate or inhibit translocation of each isozyme. The effects of altering nuclear concentration of each isozyme on transcription (5-bromouridine 5'-triphosphate (BrUTP) incorporation), amount and distribution of small nuclear ribonucleoproteins (snRNPs), nucleolar dynamics (immunocytochemistry for Smith antigen (Sm) protein) and the activity of embryonic alkaline phosphatase (EAP; histochemistry) were examined. We found that nuclear concentration of PKC epsilon correlated with total mRNA transcription. Higher nuclear concentrations of both PKC delta and epsilon decreased storage of snRNPs in Cajal bodies and decreased the number of nucleoli, but did not affect the nucleoplasmic concentration of snRNPs. Inhibiting translocation of PKC delta out of the nucleus at the early four-cell stage decreased cytoplasmic EAP activity, whereas inhibiting translocation of PKC epsilon increased EAP activity slightly. These results indicate that translocation of PKC delta and epsilon in and out of nuclei at the early four-cell stage in mice can affect transcription or message processing, and that sequestration of these PKC in nuclei can also affect the activity of a cytoplasmic protein (EAP).