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PubMed1984

Oxidation of formaldehyde and acetaldehyde by NAD+-dependent dehydrogenases in rat nasal mucosal homogenates.

Homogenates of respiratory and olfactory tissue from the rat nasal cavity were examined for their capacity to catalyze the NAD+-dependent oxidation of formaldehyde (in the presence and absence of glutathione) and of acetaldehyde. Both aldehydes were oxidized efficiently by nasal mucosal homogenates, and formaldehyde dehydrogenase (FDH) and aldehyde dehydrogenase (AldDH) were tentatively identified in both tissue samples. At least two isozymes of AldDH, differing with respect to their apparent Km and Vmax values with acetaldehyde as substrate, were found in the nasal mucosa, one of which may catalyze the oxidation of both formaldehyde and acetaldehyde. The specific activity of FDH in the olfactory mucosa was twice that in the respiratory mucosa, whereas the specific activity of the higher Km isozyme of AldDH was five to eight times greater in respiratory than in olfactory tissue. The specific activity of the lower Km isozyme of AldDH was similar in respiratory and olfactory homogenates. Repeated exposures of rats to formaldehyde (15 ppm, 6 hr/day, 10 days) or to acetaldehyde (1500 ppm, 6hr/day, 5 days) did not substantially affect the specific activities of FDH and AldDH in nasal mucosal homogenates. Glutathione is a cofactor for FDH; the concentration of nonprotein sulfhydryls in respiratory mucosal homogenates was approximately 2.8 mumoles/g and was not changed significantly by repeated exposures to formaldehyde (15 ppm, 6hr/day, 9 days). These data indicate that the rat nasal mucosa, which is the major target site for both aldehydes in inhalation toxicity studies, can metabolize both formaldehyde and acetaldehyde, and that the specific activities of formaldehyde and aldehyde dehydrogenase in homogenates of the nasal mucosa are essentially unchanged following repeated exposures to toxic concentrations of either compound.

Acetaldehyde↗
PubMed1991

Effect of glutathione manipulation on prostaglandin synthesis in renal medullary homogenates.

1. The effect of glutathione (GSH) manipulation on arachidonic acid (AA) metabolism in renal medullary (RM) homogenates was investigated. 2. Diethyl maleate (DEM) depleted GSH initially by 50% (P less than 0.05) and produced a general suppression (P less than 0.05) of all PGs with the exception of TXB2. GSH was further depleted during homogenization and a 30-min incubation period (P less than 0.01). 3. Adding glutathione monoethyl ester (GSH-MEE) (0, 0.8, 1.6 or 3.2 mmol/ml) to RM homogenates increased GSH (P less than 0.01) and decreased RM homogenates' PGs-synthesizing capability (P less than 0.05), with the exception of PGE2 and TXB2 at the highest concentration. 4. The results indicate that homogenization has a significant impact (P less than 0.05) on GSH concentration of the media and alterations in GSH concentration affect the profile and quantity of AA metabolites in renal medullary homogenates.

Animals↗
PubMed1988

Inhibition of brain cation pump enzyme by in vitro lead ion: effects of low level [Pb] and modulation by homogenate.

Rat brain homogenates were preincubated with lead chloride for 20 min at 0 degrees C. Inhibition of K-pnitrophenylphosphatase (K-pNPPase), which measures the dephosphorylation step of Na,K-ATPase, reached steady state within 10 min and was readily reversible. The activity in brain, homogenates prepared from 60-day-old rats, expressed (mean +/- SE) as a percentage of control (100.0 +/- 0.48%), fell to 89.4 +/- 0.52% at 0.25 microM [Pb] to 64.2 +/- 1.65% at 5 microM [Pb]. However, between 5 and 25 microM [Pb] K-pNPPase activity significantly increased (to 85.4 +/- 3.14% at 25 microM) before it again fell above 30 microM. Similar results were obtained with brain homogenates prepared from 10-day-old rats. The multiphasic nature of this dose-response curve did not change with changes in buffer, substrate, anion, test tube order, or test tube composition (glass vs plastic), and appeared to be intrinsic to homogenate-Pb interactions. Microsomal preparations also exhibited multiphasicity, but with a shift in the inflection points. However, there was no multiphasicity with commercial hog brain Na,K-ATPase, suggesting an interaction between a component in the rat brain preparations and lead ion. Addition of boiled rat brain homogenate to commercial Na,K-ATPase resulted in partial protection from lead inhibition but did not produce multiphasicity over the ranges tested. Bovine serum albumin provided less protection. We conclude that there is a complex interaction among K-pNPPase activity, some factor in the rat brain homogenate, and low levels of lead ion.

4-Nitrophenylphosphatase↗
PubMed1985

Mutagenicity of some dialkylnitrosamines, cyclic nitrosamines and N,N-diethanolnitrosamine in Salmonella typhimurium with rat and rabbit nasal, lung and liver S9 homogenates.

6 nitrosamines, 5 of which cause rat nasal cancer, were tested for mutagenicity in the TA100 strain of S. typhimurium with rat and rabbit nasal, lung and liver S9 homogenates. The TA98 strain also was used with rabbit tissue homogenates. The two cyclic nitrosamines tested, N-nitrosopiperidine and N-nitrosopyrrolidine, were substantially mutagenic with all rabbit tissue homogenates in TA100, but in the rat only nasal homogenate was effective in activating them. N-Nitrosodi(n)propylamine also was activated by rat nasal tissue homogenate but not by the other rat or rabbit tissue homogenates. Diethanolnitrosamine was a direct mutagen in both TA100 and TA98. N-Nitrosodimethylamine and N-nitrosodiethylamine were not mutagenic under any test conditions. The results indicate that some nitrosamines that cause nasal cancer can be activated by nasal enzymes and that possibly important differences in activating capabilities occur among respiratory tract and hepatic tissues and among animal species.

Animals↗
PubMedDate not supplied

Relative stability of alpha-melanotropin and related analogues to rat brain homogenates.

alpha-Melanotropin (alpha-MSH) retains less than 1% of its original activity after a 60 min incubation with 10% rat brain homogenate. [Nle4,D-Phe7]-alpha-MSH is nonbiodegradable in rat serum (240 min incubation) and still maintains 10% of its original activity in 10% rat brain homogenate (240 min incubation). The related fragment analogue, Ac-[Nle4,D-Phe7]-alpha-MSH4-10-NH2, retains 50% of its activity after a 240 min incubation in rat brain homogenate, whereas Ac-[Nle4,D-Phe7]-alpha-MSH4-11-NH2 is totally resistant to inactivation by rat brain homogenate. Both [Nle4,D-Phe7]-fragments are resistant to degradation by rat serum, but [Nle4]-alpha-MSH, Ac-[Nle4]-alpha-MSH4-10-NH2 and Ac-[Nle4]-alpha-MSH4-11-NH2 are rapidly inactivated under both conditions. The cyclic melanotropin, [Cys4,Cys10]-alpha-MSH, is inactivated in rat brain homogenate as is the shorter Ac-[Cys4,Cys10]-alpha-MSH4-10-NH2 analogue, but neither cyclic melanotropin is inactivated upon incubation in serum from rats. Ac-[Cys4,D-Phe7,Cys10]-alpha-MSH4-10-NH2 is resistant to inactivation by either rat serum or a brain homogenate. Some of these melanotropin analogues may provide useful probes for the localization and characterization of putative melanotropin receptors in both the central nervous system and peripheral tissues.

Animals↗
PubMed1995

Properties of the omega-hydroxylation system of docosahexaenoic or arachidonic acid in brain or liver homogenate of rat.

The homogenate of a brain or liver obtained from a 1-55-day-old rat was incubated with NADPH and docosahexaenoic or arachidonic acid as the substrate. omega-Hydroxydocosahexaenoic or omega-hydroxyeicosatetraenoic acid from an incubation mixture of the homogenate was detected on a selected-ion monitoring chromatogram of reversed phase-HPLC-thermospray-mass spectrometry. omega-Hydroxylation activity in the brain homogenate considerably increased with growth up to 55 days. Activity in the liver homogenate decreased much with growth up to 55 days. omega-Hydroxylation activity in homogenates of rat brain gray matter, white matter, medula oblongata and cerebellum was much the same. omega-Hydroxylation activity of docosahexaenoic acid in rat brain homogenate was maximal at pH 7.5-8.0 in 50 mM Tris-HCl buffer and was inhibited by CO gas, metyrapone, ADP-Fe3+, heat treatment at 100 degrees C for 5 min and without NADPH. Based on these results, it is suggested that omega-hydroxylation activity is associated with cytochrome P-450 without NADPH-ADP-Fe(3+)-dependent lipid peroxidation, and the omega-hydroxylation system may be a metabolic pathway of the fatty acids in adult rat brain or neonatal rat liver. Since omega-hydroxyeicosatetraenoic acid produces relaxation of artery, it is suggested that blood flow changes in rat brain or liver with growth are caused by omega-hydroxylation activity changes in these organs with growth.

Animals↗
PubMed1984

Dephosphorylation of WR-2721 with mouse tissue homogenates.

Mouse liver homogenate had an optimum pH of 8.6 to 8.8 for dephosphorylation of WR-2721 in the analyzed pH range from 5.2 to 10.0. At this optimum pH condition, the dephosphorylation activities of six mouse tissue homogenates were analyzed. Kidney, liver and small intestine homogenates showed higher dephosphorylation activities (935, 336 and 314 nmoles/mg protein/hr, respectively) than spleen and lung homogenates (86, 49 nmoles/mg protein/hr, respectively). Furthermore, serum did not show any dephosphorylation activity. The high activity found in liver homogenate agrees well with our previous data with mouse L cells. However, optimum pH from 8.6 to 8.8 in liver homogenate is quite different from the data reported by using Ehrlich ascites tumor cells (optimum pH was 5.6). Therefore, it is suggested that WR-2721 administered into mouse is efficiently dephosphorylated in certain tissues such as liver to its active form with the enzyme(s) different from that found in Ehrlich ascites tumor cells.

Amifostine↗
PubMed1996

Effects of storage and homogenization methods on the hepatic recovery of dextrans determined by size-exclusion chromatography.

The effects of storage and homogenization methods on the analytical recovery of dextran macromolecules from rat livers were investigated using a high-performance size-exclusion chromatographic (HPSEC) method. Livers were collected from rats dosed with fluorescein-labeled dextrans with molecular weights of 150 or 70 kD. Subsequently, the livers were subjected to different methods to study the effects of the following parameters on the hepatic recovery of dextrans: storage method (freezing the livers before homogenization or freezing the homogenates); contents of the homogenization buffer (addition of 1% Triton X-100); and sample type (HPSEC analysis of the whole homogenate or the supernatant after centrifugation). It is shown that in the absence of Triton in the homogenization buffer, the hepatic recovery of dextrans is substantially affected by all the factors studied. However, in the presence of 1% Triton in the buffer, the hepatic recoveries were maximal and independent of the storage method or sample type. These studies suggest that for optimal recovery of dextran macromolecules from the liver, a sample preparation method capable of disrupting the subcellular membranes should be used.

Analysis of Variance↗
PubMed2006

Cytosolic and localized inhibition of phosphodiesterase by atrazine in swine tissue homogenates.

Atrazine (ATR) significantly inhibited phosphodiesterase (PDE) in crude homogenates of swine heart, brain, and lung, but not liver or kidney tissues. Except for heart, PDE activities in the cytosolic fraction of the tissue homogenates were not affected by ATR. The inhibition of the PDE activity in the cytosol from heart homogenate was not significantly different between ATR and a non-specific PDE inhibitor, 3-isobutyl-1-methylxanthine (IBMX). Dixon plots of the crude tissue homogenates showed that heart and brain were inhibited via two different mechanisms (competitive or mixed inhibition, and noncompetitive inhibition, respectively), suggesting that ATR may be a semi-specific PDE inhibitor. Furthermore, in crude tissue homogenates, ATR did not inhibit PDE as effectively as IBMX suggesting that there are ATR-susceptible and ATR-nonsusceptible forms of PDE. Association constants for ATR were 55 microM for heart and 310 microM for brain. The stability of the activity of PDE was affected by freezing, requiring the use of only freshly prepared tissue homogenates.

1-Methyl-3-isobutylxanthine↗
PubMed2005

Effect of beta-sitosterol concentration and high pressure homogenization on the chlorhexidine release from vesicular gels.

Previous studies have confirmed that the phase transition of vesicular gels of hydrogenated phospholipids to the less ordered fluid vesicular state was induced by the increase of the beta-sitosterol ratio in the whole gel system and consequently in the lipid bilayer. The purpose of the present study was to evaluate the influence of the beta-sitosterol portion in the lipid bilayer and the effect of high pressure homogenization on the structural characteristics of the prepared gel systems. In addition the influence of beta-sitosterol on the consequent chlorhexidine release from the obtained vesicles and liposomes was also examined. Lipid mixtures were prepared from different molar ratios of lecithin:sterol components (90:10-65:35 mol%). The obtained mixtures were hydrated with the aqueous solution of chlorhexidine digluconate in order to achieve a 30% (w/w) final concentration of the lipid mixtures and a 4% (w/w) concentration of the drug. One portion of the resultant multilamellar vesicles was homogenized by using high pressure. To characterize the homogenized and non-homogenized systems, transmission electron microscopy of the freeze-fractured samples and differential scanning calorimetry (DSC) were carried out. A vertical type diffusion cell was applied to determine the amount of released chlorhexidine digluconate. Along with the increase in beta-sitosterol concentration, the fluidity of the membrane as well as its permeability also increased. The increased permeability--caused by the higher beta-sitosterol concentration--and the high pressure homogenization, which increased the dispersity and therefore the surface area, enabled a higher amount of chlorhexidine to be released. The increase of drug release was more pronounced in the case of samples prepared with high pressure homogenization.

Anti-Infective Agents, Local↗
PubMed2006

Extreme between-study homogeneity in meta-analyses could offer useful insights.

OBJECTIVES: Meta-analyses are routinely evaluated for the presence of large between-study heterogeneity. We examined whether it is also important to probe whether there is extreme between-study homogeneity. STUDY DESIGN: We used heterogeneity tests with left-sided statistical significance for inference and developed a Monte Carlo simulation test for testing extreme homogeneity in risk ratios across studies, using the empiric distribution of the summary risk ratio and heterogeneity statistic. A left-sided P=0.01 threshold was set for claiming extreme homogeneity to minimize type I error. RESULTS: Among 11,803 meta-analyses with binary contrasts from the Cochrane Library, 143 (1.21%) had left-sided P-value <0.01 for the asymptotic Q statistic and 1,004 (8.50%) had left-sided P-value <0.10. The frequency of extreme between-study homogeneity did not depend on the number of studies in the meta-analyses. We identified examples where extreme between-study homogeneity (left-sided P-value <0.01) could result from various possibilities beyond chance. These included inappropriate statistical inference (asymptotic vs. Monte Carlo), use of a specific effect metric, correlated data or stratification using strong predictors of outcome, and biases and potential fraud. CONCLUSION: Extreme between-study homogeneity may provide useful insights about a meta-analysis and its constituent studies.

Databases, Bibliographic↗
PubMed1997

Determination of daily sperm production in stallion testes by enumeration of germ cells in homogenates.

Thirty adult stallion testes were selected with high (n = 15) and low (n = 15) Daily Sperm Production (DSP)/testis. Parenchymal samples were prepared for morphometric analysis, and the numbers of germ cells and Sertoli cells were determined. Testicular samples were homogenized, and germ cells and Sertoli cells were enumerated using phase contrast microscopy. Numbers of germ cells and Sertoli cells and potential DSP during spermatogenesis were determined. Significant correlations existed between morphometric and homogenate determinations of number per testis of preleptotene, leptotene plus zygotene primary spermatocytes (r = 0.58; P < 0.001), pachytene plus diplotene primary spermatocytes (r = 0.67; P < 0.0001), all primary spermatocytes (r = 0.67; P < 0.0001), round spermatids (r = 0.72; P < 0.0001), and Sertoli cells (r = 0.70; P < 0.0001). Significant correlations (P < 0.0001) existed between morphometric and homogenate determination of DSP/testis based on preleptotene, leptotene plus zygotene primary spermatocytes (r = 0.78), pachytene plus diplotene primary spermatocytes (r = 0.88), and round spermatids (r = 0.85). Using morphometric determination as the standard, the sensitivity (i.e., ability to detect low DSP/testis) and specificity (i.e., ability to detect high DSP/testis) by homogenate enumeration of germ cells was 81 and 93% for round spermatids, 100 and 24% for pachytene plus diplotene primary spermatocytes, and 67 and 87% for preleptotene, leptotene plus zygotene primary spermatocytes, respectively. Enumeration of primary spermatocytes in homogenates was less accurate than enumeration of round or elongated spermatids. Enumeration of round and elongated spermatids in homogenates was a rapid and useful method for determining DSP in horses, and it may prove to be a useful technique for quantitating potential DSP from testicular biopsies.

Journal Article↗
PubMed2001

Effect of cyanide concentrations on the secondary structures of protein in the crude homogenates of the fish gill tissue.

The effect of cyanide concentrations on the secondary conformation of protein in the fish gill homogenate was determined using an attenuated total reflectance (ATR)/Fourier transform infrared (FT-IR) microspectroscopy. Gills from male Tilapia zillii were isolated and homogenized in pH 8.0 Tris buffer solution and subjected to FT-IR study. The results indicate that the amide I and III bands of protein in fish gill homogenate deformed markedly with the increase of cyanide concentration. The fish gill homogenate shows a maximum peak at 1650 cm(-1) in amide I band, suggesting the predominant proportion of alpha-helical conformation. Once the KCN was added into the gill homogenate, the maximum peak shifted gradually from 1650 to 1643 cm(-1) due to the random coil structure, with the increase of cyanide concentration used. Two additional shoulders at 1657 (alpha-helix) and 1627 (beta-sheet) cm(-1) also appeared gradually, implying that the cyanide can in part induce changes in protein conformation of fish gill homogenate from alpha-helix to random coil and beta-sheet conformations.

Animals↗
PubMed2003

Isolation of Salmonella from alfalfa seed and demonstration of impaired growth of heat-injured cells in seed homogenates.

Three major foodborne outbreaks of salmonellosis in 1998 and 1999 were linked to the consumption of raw alfalfa sprouts. In this report, an improved method is described for isolation of Salmonella from alfalfa seed lots, which had been implicated in these outbreaks. From each seed lot, eight samples each containing 25 g of seed were tested for the presence of Salmonella by the US FDA Bacteriological Analytical Manual (BAM) procedure and by a modified method applying two successive pre-enrichment steps. Depending on the seed lot, one to four out of eight samples tested positive for Salmonella by the standard procedure and two to seven out of eight samples tested positive by the modified method. Thus, the use of two consecutive pre-enrichment steps led to a higher detection rate than a single pre-enrichment step. This result indirectly suggested that Salmonella cells on contaminated seeds might be injured and failed to fully resuscitate in pre-enrichment broth containing seed components during the first 24 h of incubation. Responses of heat-injured Salmonella cells grown in buffered peptone water (BPW) and in three alfalfa seed homogenates were investigated. For preparation of seed homogenates, 25 g of seeds were homogenized in 200 ml of BPW using a laboratory Stomacher and subsequently held at 37 degrees C for 24 h prior to centrifugation and filtration. While untreated cells grew at about the same rate in BPW and in seed homogenates, heat-injured cells (52 degrees C, 10 min) required approximately 0.5 to 4.0 h longer to resuscitate in seed homogenates than in BPW. This result suggests that the alfalfa seed components or fermented metabolites from native bacteria hinder the repair and growth of heat-injured cells. This study also shows that an additional pre-enrichment step increases the frequency of isolation of Salmonella from naturally contaminated seeds, possibly by alleviating the toxic effect of seed homogenates on repair or growth of injured cells.

Colony Count, Microbial↗
PubMed1999

The effect of homogenization of whole milk, skim milk and milk fat on nisin activity against Listeria innocua.

Whole milk, skim milk and an emulsion of milk fat in water, inoculated with approx. 10(5) cfu/ml of Listeria innocua, were treated at 30 degrees C with 100 IU/ml of nisin, homogenization at 200 bar or both procedures. Nisin activity and survival of L. innocua after treatments were determined. Recovery of nisin activity from non-homogenized whole milk treated with 100 IU/ml of nisin was complete, whereas a loss of 18 to 28% of activity was detected in non-homogenized fat-in-water emulsion. Loss in nisin activity due to homogenization represented up to 64% in whole milk and 62% in fat-in-water emulsion. Nisin addition by itself achieved a reduction in L. innocua counts of 3.7-3.8 log units in whole milk and 3.6 log units in fat-in-water emulsion compared to numbers in untreated samples. When nisin-containing whole milk and fat-in-water emulsion were homogenized, L. innocua counts were only reduced by 2.6-2.9 log units and 2.5 log units, respectively, compared to numbers in untreated samples. Homogenization of nisin-containing skim milk resulted in a loss of nisin activity of 20% but achieved a reduction of 3.0 log units in L. innocua counts.

Animals↗
PubMed2003

Treatment planning for lung cancer: traditional homogeneous point-dose prescription compared with heterogeneity-corrected dose-volume prescription.

PURPOSE: To quantify the differences in doses to target volumes and critical thoracic structures calculated by traditional homogeneous point-dose prescription and heterogeneity-corrected volume-dose prescription. METHODS AND MATERIALS: Between 1998 and 2001, 30 patients with inoperable Stage I/II non-small-cell lung cancer underwent radiation treatment planning at our institution. A commercially available convolution/superposition- based algorithm was used. Three treatment plans were calculated for each patient using identical beam geometries: one plan was generated by traditional homogeneous point-dose prescription, a second by the traditional method with heterogeneity correction, and a third by heterogeneity-corrected volume-dose prescription that would cover 95% of the planned target volume (PTV). Target volume coverage, isocenter dose, and dose uniformity in the second and third plans were compared. RESULTS: The PTV, clinical target volume (CTV), and isocenter calculated by the heterogeneity-corrected volume-dose method were equivalent to those calculated by the traditional homogeneous point-dose method with heterogeneity correction. The fraction of the PTV covered by heterogeneity-corrected volume-dose prescription was significantly greater than the fraction covered by traditional homogeneous point-dose prescription with heterogeneity correction (p = 0.05). The dose prescribed using the traditional method would have been delivered to less than 90% of the PTV in 14 of 30 patients. There was no significant difference in the maximum and minimum doses to the PTV, the CTV, or the isocenter calculated by the traditional homogeneous method with heterogeneity correction and the heterogeneity-corrected volume-dose method. There was also no significant difference in the planned volume of lung receiving greater than 20 Gy as calculated by these two methods. CONCLUSION: When compared with traditional homogeneous radiation treatment planning, heterogeneity-corrected methods produce equivalent PTV, CTV, and isocenter doses while providing superior PTV coverage.

Carcinoma, Non-Small-Cell Lung↗
PubMed2001

Delineating relative homogeneous G+C domains in DNA sequences.

The concept of homogeneity of G+C content is always relative and subjective. This point is emphasized and quantified in this paper using a simple example of one sequence segmented into two subsequences. Whether the sequence is homogeneous or not can be answered by whether the two-subsequence model describes the DNA sequence better than the one-sequence model. There are at least three equivalent ways of looking at the 1-to-2 segmentation: Jensen-Shannon divergence measure, log likelihood ratio test, and model selection using Bayesian information criterion. Once a criterion is chosen, a DNA sequence can be recursively segmented into multiple domains. We use one subjective criterion called segmentation strength based on the Bayesian information criterion. Whether or not a sequence is homogeneous and how many domains it has depend on this criterion. We compare six different genome sequences (yeast S. cerevisiae chromosome III and IV, bacterium M. pneumoniae, human major histocompatibility complex sequence, longest contigs in human chromosome 21 and 22) by recursive segmentations at different strength criteria. Results by recursive segmentation confirm that yeast chromosome IV is more homogeneous than yeast chromosome III, human chromosome 21 is more homogeneous than human chromosome 22, and bacterial genomes may not be homogeneous due to short segments with distinct base compositions. The recursive segmentation also provides a quantitative criterion for identifying isochores in human sequences. Some features of our recursive segmentation, such as the possibility of delineating domain borders accurately, are superior to those of the moving-window approach commonly used in such analyses.

Base Composition↗
PubMed1997

Volume of luteal tissue and concentration of serum progesterone in cows bearing homogeneous corpus luteum or corpus luteum with cavity.

Ultrasonographical examinations of ovarian structures were performed in 27 inseminated cows at estrus days and on days 4, 9, 20, 25, 30, and 40 after ovulation. Three cows were used twice. Corpora lutea (CLs) with a cavity were compared with homogeneous CLs. in pregnant and nonpregnant cows. Diameters and volumes of CLs and cavities, as well as volumes of luteal tissue and concentrations of serum progesterone were determined. The volumes of the structures were calculated using a mathematical formula for a rotary ellipsoid. Homogeneous CLs and CLs with a cavity and their luteal tissue reached a maximum volume in nonpregnant and pregnant cows on day 9 after ovulation. At this time, CLs volumes were 7.52 +/- 3.14 (homogeneous CLs, n = 4) and 4.54 cm3 (CLs with a cavity, n = 1) in nonpregnant cows, and 6.05 +/- 1.71 (homogeneous CLs, n = 10) and 9.54 +/- 2.67 cm3 (CLs with a cavity, n = 15) in pregnant cows. The volumes of luteal tissue were 7.52 +/- 3.14 and 4.33 cm in nonpregnant cows and 6.05 +/- 1.71 and 8.62 +/- 3.46 cm3 in pregnant cows. Concentrations of progesterone in peripheral blood in pregnant cows bearing a homogeneous CLs or CLs with a cavity on day 9 were 3.15 +/- 0.69 ng ml-1 and 4.12 +/- 1.28 ng ml-1, respectively. The concentrations of progesterone were higher in pregnant cows in comparison with nonpregnant cows. CLs with a cavity in pregnant cows contained a higher volume of luteal tissue and higher secretory activity compared to homogeneous.

Animals↗