Concentration of anti-Müllerian hormone in dairy heifers is positively associated with productive herd life.

Reliable biomarkers predictive of productive herd life (time in herd after birth of first calf) have heretofore not been discovered in dairy cattle. However, circulating concentrations of anti-Müllerian hormone (AMH) are positively associated with number of follicles or antral follicle count (AFC), ovarian function, and fertility, and approximately 25% of cows have a relatively low AFC and low AMH concentrations. The present study tested the hypothesis that heifers with the lowest AMH concentrations have suboptimal fertility and are removed from a herd for poor reproductive performance at a greater rate, and therefore have a shorter productive herd life compared with age-matched herdmates with higher AMH. To test this hypothesis, 11- to 15-mo-old Holstein heifers (n=281) were subjected to a single measurement of AMH. All heifers not removed from the herd had the opportunity to complete 2 lactations and start their third lactation after calving. During this time, performance and health parameters for each individual were recorded daily by herd managers. Results showed that the quartile of heifers with the lowest AMH concentration also had, on average, a shorter productive herd life (by 196 d), a reduced survival rate after birth of the first calf, the lowest level of milk production (first lactation), the lowest total percentage of cows pregnant (across all lactations), the highest culling rates (first and second lactations and overall), and the highest culling rate for poor reproduction (first lactation) compared with age-matched herdmates with higher AMH. We concluded that a single determination of AMH concentration in young adult dairy heifers may be a simple diagnostic method to predict herd longevity, and AMH may be a useful phenotypic marker to improve longevity of dairy cows.

Influence of age and gender on secretion of anti-Müllerian hormone in Asian (Elephas maximus) and African (Loxodonta africana) elephants.

Anti-Müllerian hormone (AMH) secretion was studied in Asian and African elephants varying in age and reproductive status. Overall mean concentrations did not differ (P > 0.05) between species, but were markedly higher in male than female Asian elephants (31.01 ± 4.22 ng/mL and 0.19 ± 0.02 ng/mL, mean ± SEM) and African elephants (40.27 ± 3.18 ng/mL, 0.17 ± 0.04 ng/mL), respectively. Anti-Müllerian hormone secretion was not significantly affected by ovarian cyclicity status (cycling vs noncycling), but was higher (P < 0.05) in prepubertal (0.40 ± 0.10 ng/mL) than reproductive age (8-35 y; 0.18 ± 0.04 ng/mL) and aged (≥ 36 y; 0.16 ± 0.03 ng/mL) females. In males, AMH secretion was not significantly affected by musth status, but was age-related, with higher concentrations (P > 0.05) in prepubertal (49.08 ± 6.11 ng/mL) as compared to aged (≥36 y; 22.27 ± 5.82 ng/mL) bulls; concentrations in mature bulls (8-35 y; 37.01 ± 3.17 ng/mL) were similar to prepubertal and older bulls. We concluded that circulating AMH concentrations in elephants were similar between species and not affected by reproductive status; however, concentrations were significantly higher in males than females, and in younger animals. The diagnostic value of AMH to assess fertility status of individual elephants remains to be determined.

Embryonic platelet-activating factor: an indicator of embryo viability.

BACKGROUND: A definitive need exists to identify a biomarker of embryonic viability. Platelet-activating factor (PAF) production by human embryos is related to pregnancy potential. METHODS: Conditioned embryo culture media were obtained following conventional IVF on day 3, with PAF levels and pregnancy outcomes correlated. RESULTS: Overall pregnancy rate was 68% (17/25) with a mean of 84.1 (+/- 8.5) pmol/l/embryo PAF level. PAF levels ranged from a 216.4 pmol/l/embryo (pregnant) to a 3.7 pmol/l/embryo (not pregnant). There was a significant difference (P < 0.05) in PAF content between pregnant (92.1 +/- 9.5 pmol/l/embryo) and non-pregnant groups (52.5 +/- 16.6 pmol/l/embryo). Patients were categorized into three groups based upon PAF levels: low (< or= 5 pmol/l/embryo); medium (51-100 pmol/l/embryo) and high (>100 pmol/l/embryo). The low (60%) group had a significantly (P < 0.05) lower pregnancy rate than either the medium (85%) or high (89%) groups. A receiver-operator characteristic curve predicted a cut-off limit of 45 pmol/l/embryo for PAF content in human embryo conditioned culture media. CONCLUSIONS: The data demonstrate a correlation between PAF levels in human embryo conditioned culture media and pregnancy outcome. Additionally, as embryonic PAF levels increase so does the corresponding pregnancy rate. Therefore, PAF may be used as an indicator of embryo viability and for predicting pregnancy outcome.

Exogenous platelet-activating factor stimulates cell proliferation in mouse pre-implantation embryos prior to the fourth cell cycle and shows isoform-specific stimulatory effects.

Mouse embryos secrete molecules homologous to platelet-activating factor (PAF), termed embryo-derived PAF (EPAF), which act in an autocrine/paracrine fashion to stimulate embryonic development in vitro. Mouse EPAF is thought to consist predominantly of hexadecyl (C16) and octadecyl (C18) PAF-like components. Mouse pre-implantation embryos cultured with exogenous PAF from the early cleavage stages exhibit increased blastocyst cell numbers and rates of mitosis around the 8-cell stage. We investigated whether exogenous PAF could specifically stimulate embryonic cell proliferation prior to the blastocyst stage in the mouse and also compared the biological activities of the C16 and C18 PAF isoforms as follows. Embryos were cultured for either 24 h or 120 h from the 2-cell stage and their total cell numbers were determined or their development assessed in terms of their incidence of successful zona-hatching respectively. In each case, embryos were cultured in unsupplemented medium or in medium supplemented with either C16 or C18 PAF (0.5 microM). Compared with controls, culture with C16 PAF produced a significant stimulation of mean total per number per embryo and a significant increase in the incidence of successful zona-hatching, whilst culture with C18 PAF had no significant effect. We then cultured 1-cell zygotes for 48 h in unsupplemented medium or medium supplemented with either an equimolar mixture of C16 and C18 PF or with either C16 or C18 PF alone (each at 0.2 microM). Embryos were also scored for cell number at 4 h and 30 h of culture. Although no significant effect on mean cell number per embryo was seen following 4 h or 30 h of culture with a mixed C16/C18 PAF preparation, culture for 48 h with a mixed C16/C18 PAF preparation or with C16 PAF alone produced a significant increase in mean cell number per embryo compared with controls - an effect that is likely to be receptor-mediated, since culture with an equivalent concentration of C18 PAF had no significant effect compared with controls. We have demonstrated that mouse zygotes/embryos can respond in a specific manner to exogenous hexadecyl PAF in terms of increased rates of cell proliferation prior to cavitation, and must be capable of doing so at some time between the first and third, and also between the second and fourth, cell cycles. Such embryos presumably express one or more classes of functional PAF-receptor molecule during this period (i.e. as early as during the 1-, 2- or 4-cell stages). We have also demonstrated that embryonic response to exogenous PAF is significantly isoform-specific, which may reflect differences between the two isoforms either in affinity for binding to putative embryonic PAF-receptor molecules or in their ability to elicit a stimulatory response following binding. This observation calls into question the use of preparations containing a mixture of hexadecyl and octadecyl PAF isoforms, particularly in dose-response studies, in the mouse.

Platelet-activating factor content in boar spermatozoa correlates with fertility.

The objective of this study was to evaluate the level of platelet-activating factor [1-O-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine; PAF] content in spermatozoa between two groups of boars that differ in farrow rate percentages. The boar farrow rate was defined as High if it was > or = 70% and Low if it was < 70%. Fresh, extended semen was collected from sexually mature boars and used in the PAF extractions. Platelet-activating factor was detected in all semen samples assayed. The amount of PAF detected in spermatozoa obtained from the High group ranged from 1.90 to 11.30 pM/10(6) cells. The level of PAF in the Low group ranged from 0.92 to 4.96 pM/10(6) cells. Regression analysis revealed a positive (R2 = 0.369) and significant (P = 0.021) relationship between PAF content in boar spermatozoa and farrow rate. Spermatozoa-derived PAF levels (mean +/- SEM) were significantly higher (P = 0.015) in the High-farrow group (6.75 +/- 1.25 pM/10(6) cells) than in the Low-farrow group (2.45 +/- 0.51 pM/10(6) cells). The PAF content in spermatozoa was significantly higher (P = 0.035) in the High-average (> or = 10.5/litter) number of piglets born group (5.78 +/- 1.24 pM/10(6) cells) than in the Low-average (< 10.5/litter) number of piglets born group (3.34 +/- 1.19 pM/10(6) cells). Additionally, PAF content in spermatozoa was significantly higher (P = 0.034) in the High-average (> or = 9/litter) number of piglets born alive group (6.82 +/- 1.35 pM/10(6) cells) than the Low-average (< 9/litter) number of piglets born alive group (3.00 +/- 0.87 pM/10(6) cells). The data demonstrate that PAF is present in boar spermatozoa and that levels are significantly higher in individuals with a high-farrow rate status and high-number of piglets born and born-alive.

Role of platelet-activating factor in reproduction: sperm function.

Since its discovery nearly thirty years ago, platelet-activating factor has emerged as one of the more important lipid mediators known. Platelet-activating factor (PAF; 1-O-alkyl-2-O-acetyl-sn-glycero-3-phosphorylcholine) exists endogenously as a mixture of molecular species with structural variants of the alkyl moiety. PAF is a novel potent signaling phospholipid that has unique pleiotropic biological properties in addition to platelet activation. PAF also plays a significant role in reproduction. PAF content in squirrel monkey sperm is significantly higher during the breeding season than the non-breeding season. PAF content in human sperm has a positive correlation with seminal parameters and pregnancy outcomes. High-fertility boars have significantly more PAF in their sperm than low-fertility boars. The enzymes (lyso-PAF-acetyltransferase and PAF-acetylhydrolase) necessary for PAF activation and deactivation are present in sperm. PAF-acetylhydrolase may act as a "decapacitation factor". Removal of this enzyme during capacitation may promote PAF synthesis increasing motility and fertilization. PAF also plays a significant role in the fertilization process, enhancing the fertilization rates of oocytes. Enhanced embryo development has also been reported in oocytes fertilized with PAF-treated sperm. PAF antagonists inhibit sperm motility, acrosome reaction, and fertilization, thus suggesting the presence of receptors for PAF. The PAF-receptor is present on sperm, with altered transcript levels and distribution patterns on abnormal cells. Whereas the exact mechanism of PAF in sperm function and reproduction is uncertain, its importance in normal fertility is substantial. The reproductive significance of PAF activity in sperm and fertility plus the role of PAF in the establishment of pregnancy requires further study.

Platelet-activating factor improves intrauterine insemination outcome.

OBJECTIVE: Our purpose was to investigate intrauterine insemination pregnancy rates after human spermatozoa exposure to platelet-activating factor. STUDY DESIGN: Spermatozoa were incubated with platelet-activating factor in sperm-washing medium before intrauterine insemination. Patients whose sperm were incubated with sperm-washing medium alone served as controls. Pregnancy outcome was determined by ultrasonography (fetal heartbeat). RESULTS: Patients whose sperm were treated with exogenous platelet-activating factor had a significantly (P <.05) higher pregnancy rate (40%) than patients (20%) not receiving treatment. CONCLUSION: Inclusion of platelet-activating factor into a semen processing protocol, before intrauterine insemination, will significantly improve pregnancy rates. Platelet-activating factor may have a stimulatory effect on centriole-intact spermatozoa, enhancing their motility and fertilization success and resulting in improved pregnancy rates. Additional studies will elucidate the reproductive significance of platelet-activating factor activity in spermatozoa and its role in the establishment of pregnancy.

Immunologic detection of placental lactogen during pregnancy in a mouse model: a preliminary report.

PROBLEM: To establish a rapid test differentiating ectopic from failed intrauterine gestation, using placental lactogen (PL) as a marker for placental cells. METHOD OF STUDY: Sixteen Swiss Webster mice had synchronized ovulation and were mated. Eight mice were unmated controls. Study and control mice were sacrificed at 5, 7, 9. and 11 days gestation. Uterine sections were tested for PL by immunofluorescent antibody assay, enzyme-linked immunosorbent assay, and dot blot analysis. Human endometrial samples from a missed abortion and a nonpregnant woman were also tested. RESULTS: Placental lactogen was detectable only in pregnant uterine samples (placental cells only) by all assays and was absent in the endometial glandular cells of nonpregnant uterine samples. CONCLUSION: Three methods detected placental lactogen in the pregnant mouse and human tissue. This is the first step towards developing a reliable clinical test for human endometrial samples from early pregnancy to differentiate early abortion from ectopic pregnancy.

Impact of blood serum insulin-like growth factor I on platelet-activating factor in bull spermatozoa.

The objective of this study was to examine differences in platelet-activating factor [1-O-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine; PAF] in spermatozoa between two lines of Angus beef cattle divergently selected for blood serum insulin-like growth factor I (IGF-I) concentration. Endogenous lipids were extracted from the spermatozoa and endogenous PAF content was determined by radioimmunoassay. The amount of PAF detected in spermatozoa obtained from high IGF-I bulls (n = 8) ranged from 0.145 to 3.571 pM/10(6) cells. The level of PAF extracted from spermatozoa obtained from low IGF-I- bulls (n = 5) ranged from 0.001 to 1.024 pM/10(6) cells. Polynomial regression analysis revealed a significant cubic relationship (R(2) = 0.374; F = 6.292; P < 0.05) between spermatozoa PAF content and blood serum IGF-I concentration. Spermatozoa-derived PAF levels (mean +/- SEM) were significantly higher (P < 0.05) in the high IGF-I group (1.90 +/- 0.39 pM/10(6) cells) than in the low IGF-I group (0.59 +/- 0.20 pM/10(6) cells). High IGF-I bulls have a greater than three-fold higher PAF content in their spermatozoa than low IGF-I bulls. The data demonstrate that not only is PAF present in bull spermatozoa but that levels are significantly higher in individuals with high serum IGF-I concentrations.

Comparison of the coding sequence of the platelet-activating factor receptor gene in three species.

The actions of platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) are mediated through the PAF receptor (PAFr), which is a member of G-protein coupled superfamily of receptors. Our laboratory has data showing PAF has a role(s) in reproduction in domestic animals. Porcine, bovine and caprine PAFr genes cloned in BAC vectors were sequenced. Each PAFr coding sequence (cds) in these three species is 1029 nucleotides long and contains no intervening sequences. The deduced amino acid sequences (AAS) appear to contain seven putative transmembrane domains with an extracellular N-terminus in each species. There is a common glycosylation site at the fourth asparagine residue of N-terminus. In the tail of each deduced amino acid sequence, five to six serines and five threonine residues could act as phosphorylation sites, which play an important role in rapid receptor desensitization. The degree of homology of the three species is from 89 to 96% in nucleotide sequences (NtS), and 87-96% in identities (I) and 94-97% in positives (P) in amino acid sequences (AAS). The degree of homology with human, guinea pig, mouse and rat is 84-87, 82-88 and 83-88% in NtS, 77-84 (I) or 85-90 (P), 77-84 (I) or 85-90 (P) and 75-83 (I) or 87-90% (P) in AAS for caprine, bovine and pig, respectively. Southern blotting results suggested that the PAFr gene exists as a single copy in the genome of pig.

Elevated circulating concentrations of platelet activating factor in preeclampsia.

OBJECTIVE: The aim of this study was to determine whether any association exists between preeclampsia and circulating platelet activating factor levels. STUDY DESIGN: We performed a cross-sectional observational study of circulating platelet activating factor concentrations in nonpregnant women, normotensive pregnant women in the third trimester, women with preeclampsia in the third trimester, and normotensive men. Platelet activating factor concentrations were measured with a commercially available platelet activating factor-specific radioimmunoassay (NEN Life Science Products, Inc, Boston, Mass). The primary outcome measure was the difference in mean platelet activating factor concentrations among the 4 study groups. Preeclampsia was determined according to the criteria of The American College of Obstetricians and Gynecologists. Data were analyzed with the Student t test, the chi(2) test, the Fisher exact test, analysis of variance, and the Tukey test for pairwise multiple comparisons, with significance established at P <.05. RESULTS: The mean (+/-SD) circulating concentration of platelet activating factor was significantly higher in the group with preeclampsia (338.1 +/- 26.9 ng/mL) than in either the normotensive pregnant group (217.9 +/- 25.9 ng/mL; P <.05) or the nonpregnant female group (237.9 +/- 20.9 ng/mL; P <.05). The 2 pregnant groups were similar with respect to selected demographic characteristics and gestational age at time of collection. There were no significant differences in the mean platelet activating factor concentrations between the group with preeclampsia and the normotensive male group or between the normotensive pregnant female group and the nonpregnant female group. CONCLUSION: Circulating platelet activating factor concentrations were increased in women with pregnancies complicated by preeclampsia with respect to those in normotensive pregnant women and normotensive nonpregnant women. Platelet activating factor may therefore serve as a marker for the risk of preeclampsia.

Platelet-activating factor content in human spermatozoa and pregnancy outcome.

OBJECTIVE: To determine whether platelet-activating factor (PAF) content in human spermatozoa from an isolated population is related to fertilization and pregnancy outcome. DESIGN: Prospective analysis of PAF content in human spermatozoa after a Percoll gradient wash and its relation to fertilization and pregnancy outcome. SETTING: University-based reproductive genetics laboratory. SUBJECT(S): Couples undergoing assisted reproduction. INTERVENTION(S): Lipids extracted from Percoll gradient spermatozoa were quantitated for PAF content by a specific radioimmunoassay. MAIN OUTCOME MEASURE(S): The relation between spermatozoa-derived PAF levels and motility, concentration, morphology, and fertilization and pregnancy rates were determined by using regression analysis and the Student t-test. RESULT(S): Radioimmunoassay and regression analysis showed a significant and positive relation between PAF content in human spermatozoa and concentration and motility indices and implantation rate. Patients who became pregnant had a significantly higher PAF content in the spermatozoa used (7.285 pmol/10(6) cells) than did patients who did not become pregnant (2.990 pmol/10(6) cells). CONCLUSION(S): The PAF content in human spermatozoa has a significant and positive relation with motility and concentration indices and implantation rate. Pregnancy rates but not fertilization rates may be predicted by measuring PAF levels in an isolated subpopulation of human spermatozoa.

Presence of ribonucleic acid in human spermatozoa: differences in content between normal and abnormal spermatozoa.

OBJECTIVE: Our purpose was to determine whether there are any differences in total ribonucleic acid content between normal and abnormal human spermatozoa. STUDY DESIGN: Spermatozoa were obtained from men undergoing routine semen analysis at a university-based reproductive genetics laboratory. Specimens were classified as normal or abnormal according to World Health Organization criteria. Total ribonucleic acid was removed by acid-phenol extraction, and ribonucleic acid expression levels were determined by spectrophotometric analysis. RESULTS: Abnormal spermatozoa were found to have significantly more ribonucleic acid (0.14 +/- 0.02 mg/10(6) spermatozoa) than normal spermatozoa (0.05 +/- 0.01 mg/10(6) spermatozoa; P <.001). CONCLUSION: Ribonucleic acid content is significantly altered in abnormal spermatozoa, and this alteration may be the result of some defect in the posttranscriptional pathway.

Expression of the platelet-activating factor receptor in human spermatozoa: differences in messenger ribonucleic acid content and protein distribution between normal and abnormal spermatozoa.

OBJECTIVE: To determine the expression and distribution of the platelet-activating factor (PAF) receptor in normal and abnormal specimens of human spermatozoa. DESIGN: Prospective analysis of membrane-bound PAF receptors by immunofluorescence and PAF receptor messenger RNA by quantitated reverse transcription-polymerase chain reaction in normal and abnormal spermatozoa. SETTING: University-based reproductive genetics laboratory. PATIENT(S): Men undergoing routine semen analysis. INTERVENTION(S): Normal and abnormal spermatozoa were exposed to rabbit anti-PAF receptor antibody, fluorescein isothiocyanate-conjugated goat anti-rabbit antibody, and fluorescent microscopy or subjected to RNA isolation by acid-phenol extraction and quantitated (MIMIC Construction Kit [Clontech Laboratories, Inc., Palo Alto, CA]) reverse transcription-polymerase chain reaction. MAIN OUTCOME MEASURE(S): Fluorescent intensities at six locations along spermatozoa (end piece, principal tail, midpiece, neck, proximal head, and acrosomal region) and PAF receptor expression (messenger RNA) levels. RESULT(S): Immunofluorescence demonstrated a significant difference in PAF receptor distribution between normal and abnormal human spermatozoa, specifically at the neck region. Additionally, abnormal spermatozoa were found to have statistically significantly more PAF receptor messenger RNA than normal spermatozoa. CONCLUSION(S): Platelet-activating factor receptor expression and distribution are significantly altered in abnormal spermatozoa and this may be the result of some defect in gene transcription.

Platelet-activating factor increases intracellular calcium levels in preimplantation stage embryos.

Platelet-activating factor [1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine;PAF] has an active role in preimplantation embryo development. PAF has been shown to act via the receptor mediated inositol triphosphate-diacylglycerol (IP3/DAG) pathways in non-reproductive cells to increase intracellular calcium ([Ca++]i) levels. Molecular evidence on the presence of the PAF-receptor in mouse preimplantation embryos has recently been reported, however the effect of PAF on embryonic [Ca++]i is unclear. Therefore, the study objective was to determine the effect of PAF on [Ca++]i in the mouse preimplantation embryo. Two-cell embryos were collected from PMSG/hCG primed mature female CFW mice, washed in modified M16 (phenol red free) and loaded with FURA-2AM (0.2 microM). Background [Ca++]i levels were measured for a minimum of 120 seconds prior to treatment. PAF or lyso-PAF (the biological inactive form) were added [10-7 M final concentration] and [Ca++]i levels measured. Background, nonstimulated, [Ca++]i levels had a mean of 131.4 nM. [Ca++]i levels began to increase by 4.6 seconds with maximum levels reached by 179.9 seconds after PAF exposure, baseline levels returned by 460 seconds. Maximum [Ca++]i levels (405.9 nM mean) were 3X that of non-PAF or lyso-PAF exposure. The results further demonstrate the magnitude of PAFs' action in the preimplantation embryo period. PAF's mechanism of action, in preimplantation mouse embryos, appears to involve a PAF-receptor mediated increase in intracellular calcium.

Presence of platelet-activating factor in rhesus (Macaca mulatta) spermatozoa.

Platelet-activating factor [1-O-alkyl-2-acetyl-sn-glycero-phosphocholine; PAF] is a unique signaling phospholipid which has been implicated in a number of biological activities (e.g., reproduction). PAF has been detected in the spermatozoa from a number of laboratory and domestic species, including, but not limited to, rabbit, bovine, and the mouse. The concentration of PAF is inversely related to human (Homo sapien) spermatozoal quality. Additionally, PAF levels are significantly higher in Bolivian squirrel monkey (Saimiri sciureus) spermatozoa obtained during the breeding season than spermatozoa obtained during the nonbreeding season. There are no reports on the presence of PAF in rhesus (Macaca mulatta) spermatozoa. Therefore, the primary objective of this study was to detect the presence of PAF in rhesus spermatozoa. A second objective was to determine if PAF spermatozoa levels differ between animals housed individually (single-caged) versus free-ranging (open corrals). Semen were collected from mature rhesus via electro-ejaculation. Spermatozoa were washed free of ejaculatory plug and quick frozen in PBS. Endogenous lipids were extracted from thawed spermatozoa and ejaculatory plugs then assayed for the presence of PAF by [125I]-radioimmunoassay. PAF was not detected in any ejaculatory plugs. PAF levels were significantly higher (P < 0.01) in spermatozoa obtained from free-ranging males (mean: 1.16 pmol/10(6) spermatozoa) than males housed individually in single cage units (mean: 0.53 pmol/10(6) spermatozoa). PAF was present in rhesus spermatozoa. Additionally, PAF levels were higher in spermatozoa obtained from corral-housed animals. Additional studies are warranted to elucidate the role of PAF in spermatozoa function.

Immunofluorescent evidence of the platelet-activating factor receptor on human spermatozoa.

OBJECTIVE: To determine the presence of the platelet-activating factor (PAF) receptor on human spermatozoa. DESIGN: Prospective analysis. SETTING: University-based reproductive biology laboratory. PATIENT(S): Spermatozoa obtained from men undergoing routine semen analysis. INTERVENTION(S): Spermatozoa (n = 10) were exposed to PAF, sheep anti-PAF antibody, and fluorescein isothiocyanate-conjugated rabbit antisheep antibody, and then evaluated by fluorescent microscopy. MAIN OUTCOME MEASURE(S): Assessment of fluorescent intensity at four locations on the spermatozoa (tail, midpiece, proximal head, and acrosome region). RESULT(S): Immunofluorescence demonstrated the presence of the PAF receptor on human spermatozoa. The PAF receptor was most prevalent at two sites on the spermatozoa: the midpiece and the proximal head. CONCLUSION(S): The PAF receptor is present on human spermatozoa. Platelet-activating factor may affect the motility of spermatozoa through a receptor-mediated mechanism at the midpiece and/or proximal head.

Presence of platelet-activating factor in squirrel monkey (Saimiri boliviensis) spermatozoa: seasonal differences.

Platelet-activating factor (1-O-alkyl-2-acetyl-sn-glycero-3-phosphoryl-choline) (PAF) is a potent signaling phospholipid which has pleiotropic biological properties in addition to platelet activation. PAF has been detected in the spermatozoa in a number of species. The concentration of PAF is inversely related to human spermatozoa quality. There are no reports on the presence of PAF in nonhuman primate spermatozoa. Therefore, the primary objective of this study was to determine if PAF is present in the spermatozoa from the squirrel monkey (which is a seasonal breeder). A second objective was to determine if PAF levels change from the breeding to the nonbreeding season. Endogenous lipids were extracted from mature Bolivian squirrel monkeys (Saimiri boliviensis) spermatozoa and assayed for the presence of PAF by [125I] radioimmunoassay. PAF was detected in all samples assayed. PAF levels were significantly higher (P < 0.01) during the breeding season (mean: 3.58 ng/10(6) spermatozoa) than the nonbreeding season (mean: 0.76 ng/10(6) spermatozoa). The data demonstrate that PAF is present in squirrel monkey spermatozoa, with higher levels found during the breeding season. Additional studies are warranted to elucidate the role of PAF in spermatozoa function.

Complement component 1 inhibitor (C1-INH) like protein on murine spermatozoa: anti-C1-INH inhibits in vitro fertilization.

We investigated if complement component 1 inhibitor-like (C1-INH-L) protein found on human spermatozoa exists on mouse spermatozoa and is relevant to reproduction. We used Western blot analysis and immunofluorescence assays to detect C1-INH on murine sperm and tested the effects of the antibodies to C1-INH and albumin (negative control) on in vitro mouse sperm motility and fertilization. C1-INH-L, with molecular weight similar to human C1-INH (100 kDa), was present on the surface of spermatozoan head and midpiece. Treating mouse sperm with anti-C1-INH reduced the mouse sperm motility (P < 0.01), in vitro fertilization (P < 0.01) and embryo development rates (P < 0.01). Anti-albumin failed to do so. We conclude that C1-inhibitor-like protein is present on mouse sperm surface and appears to be relevant to reproduction.

Influence of the preimplantation-embryo-development (ped) gene on mouse blastocyst differentiation.

Mouse preimplantation embryonic cleavage rate is dependent upon the presence or absence of the Preimplantation-embryo-development (Ped) gene; which is linked to the Qa-2 subregion of the H-2 complex. Expression of Qa-2 antigens by fast developing mouse embryos correlates with Ped gene pheno-type: Qa-2(a). It is not known if the Ped gene (Qa-2(a)) participates in cell differentiation in the preimplantation mouse blastocyst. Therefore, the study objective was to determine the differentiation of cells to the inner cell mass (ICM) and trophectoderm (TE) in Qa-2(a) positive (Ped +) and Qa-2(a) negative (Ped -) mouse blastocysts. One-cell stage embryos were recovered from the excised oviducts of PMSG (5 IU) and hCG (5 IU) primed virgin female (3-4 weeks) BALB/cByJ (Qa-2(a): Ped -) and BALB/cJ (Qa-2(a): Ped +) mice mated to fertile males (12+ weeks). Embryos were collected, 14 hr after hCG, and cultured in modified alpha-MEM, to the hatched blastocyst stage in an atmosphere of 5% CO2 in air, 95% relative humidity at 37 degrees C. Cell differentiation was determined by differential staining (bis-benzimide and propidium iodide) and fluorescence microscopy. Data were analyzed by Students t-test. There was no significant difference in total cell number between BALB/cJ (mean 139) and BALB/cByJ (mean 143) embryos. A significant difference (p < 0.001) was found in the number of cells differentiating to the ICM between BALB/cJ (mean 59.0) and BALB/cByJ (mean 29.0) mouse embryos. The number of cells differentiating to the TE, between BALB/cJ (mean 80.0) and BALB/cByJ (mean 114) embryos, approached significance (p = 0.062). The results suggest that the Ped gene (Qa-2(a)) may have an influential role in preimplantation blastocyst cell differentiation. Additional studies are warranted to further elucidate the role of the Ped gene in preimplantation embryo development and blastocyst formation.