Cytoplasmic extrusion and the switch from creatine kinase B to M isoform are completed by the commencement of epididymal transport in human and stallion spermatozoa

Although in several species there is a relationship between epididymal sperm transport and fertility, in human in vitro fertilization (IVF), spermatozoa recovered from the caput epididymidis or even the rete testis are fertile. We studied two objective markers of sperm maturity in the sperm of men and stallions: creatine kinase (CK) concentrations, which are a measure of cytoplasmic retention in immature spermatozoa, and the ratio of CK-M and CK-B isoforms (% CK-M/[CK-M + CK-B]), which is proportional to the incidence of mature sperm. The CK markers and the fertilizing function are closely related: Immature sperm with cytoplasmic retention do not bind to the zona, because during cytoplasmic extrusion, the sperm plasma membrane is also remodeled. We examined whether changes in sperm CK values are still ongoing during epididymal transport, or if cellular maturation is completed prior to the arrival of sperm in the caput epididymidis. The incidences of mature sperm in human caput and corpus epididymidis (studied in six men with obstructive azoospermia of various pathogeneses) were (mean+/-SEM) 55.7+/-2.2 and 49.3+/-7.6%, respectively; and the sperm CK-M ratios in the caput epididymidis of three men were 72, 75, and 70%, values that are similar to those of ejaculated sperm. In four segments of the proximal and distal epididymis of three stallions (the origin of sperm was also verified by the position of the cytoplasmic droplet) and in ejaculate of five stallions, the incidences of mature sperm were 88.2+/-6.2, 89.0+/-6.7, 90.3+/-7.8, 87.6+/-5.9, and 86.7+/-0.8%, and the respective CK-M ratios were 75.0+/-8.7, 84.2+/-2.9, 87.9+/-1.2, 92.5+/-1.5, and 69.3+/-3.5%. There were no differences in the incidences of mature and immature spermatozoa or in CK-M ratios among sperm arising from the various epididymal regions or from the ejaculate in men or stallions. Thus, the cellular maturation events in sperm, as detected by the CK markers, are completed by the time the sperm commences epididymal transport. These findings are in agreement with the IVF fertility of sperm aspirated from the male reproductive tract. The data may also suggest that the primary role of sperm epididymal transport in men is to remodel the plasma membrane to enhance sperm functional integrity in the diverse environments of the male and female reproductive tracts prior to fertilization.

Effects of developmental exposure to indole-3-carbinol or 2,3,7,8-tetrachlorodibenzo-p-dioxin on reproductive potential of male rat offspring

Treatment of pregnant female Sprague-Dawley rats on Gestational Day 15 with a single oral dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (0.5, 1.0, or 2.0 micrograms/kg) or indole-3-carbinol (I3C, 1.0 or 100 mg/kg), an aryl hydrocarbon (Ah) receptor agonist which is found in cruciferous vegetables, resulted in reproductive abnormalities in the male offspring (three to five litters in each treatment group). Anogenital distance and crown to rump length were altered by both compounds; however, the timing of the effects (Day 1 or 5) was variable and the responses were not necessarily dose-dependent. In 62-day-old offspring, seminal vesicle (24 to 26%), prostate (32 to 44%), testicular parenchymal (14%), and epididymal weight (19%) were decreased by one or more doses of TCDD. In contrast, I3C at one or more doses decreased daily sperm production/g testicular parenchyma (13 to 20%) and daily sperm production/testis (22%). Total number of sperum in the epididymis was significantly decreased (30 to 33%) in rats perinatally exposed to TCDD and this was due to a decreased (49 to 51%) number of sperm in the tail of the epididymis. Perinatal exposure to I3C did not affect any of these parameters. TCDD did not affect epididymal transit time of sperm through the complete epididymis at any of the doses (0.5 to 2.0 micrograms/kg). However, at the two highest doses (1.0 and 2.0 micrograms/kg), TCDD increased epididymal transit rate of sperm through the tail of the epididymis by 33 and 37%, respectively. In contrast, primarily due to decreased transit rate (39%) of sperm through the head plus body of the epididymis. I3C (1 mg/kg) significantly increased total epididymal transit time by 31%. In conclusion, perinatal exposure of pregnant rats to I3C, an Ah receptor agonist similar to TCDD, causes reproductive abnormalities in male rat offspring; however, I3C and TCDD elicited both common and different responses.

Use of pregnancy-specific protein-B and estrone sulfate for determination of pregnancy on Day 49 in fallow deer ()

The objective of this study was to determine if pregnancy specific protein-B (PSPB) and estrone sulfate (E(1)SO(4)) could be used to determine pregnancy status in fallow deer (Dama dama ). Forty mature does were synchronized for estrus with an intravaginal progesterone-releasing device (CIDR) and then artificially inseminated via laparoscopy with frozen semen on one day. Ultrasound examination and jugular blood sampling were done 49 days later. Transrectal ultrasonography was done to presumptively determine the pregnancy status at the time of blood sampling. Serum estrone sulfate concentrations were significantly (P < 0.05) greater in pregnant (n=31) than nonpregnant (n=9) females at 49 days of gestation (166.7 +/- 25.9 pg/ml vs 36.3 +/- 11.1 pg/ml, respectively). The percentage of [(125)I]PSPB bound was significantly (P < 0.01) lower when sera of pregnant (n=29) versus nonpregnant (n=9) females was added to RIA tubes (63.7 +/- 1.6% vs 98.1 +/- 1.6%, respectively). There were 30 fawns born from the group of females that were diagnosed pregnant based on ultrasound. We conclude that estrone sulfate and PSPB can be used to determine pregnancy status in fallow deer at 49 days of gestation.

Use of progesterone in microspheres for maintenance of pregnancy in mares

Administration of progesterone in poly(d-,l-lactide) microspheres was used to maintain pregnancy in mares after luteolysis was induced by treatment with prostaglandin F2 alpha at day 14 of pregnancy. Mares were given vehicle only (control, n = 6) or 0.75 g (n = 7), 1.5 g (n = 8), or 2.25 g (n = 5) of microencapsulated progesterone at days 12 and 22 of pregnancy. Serum progesterone concentrations were determined daily, and pregnancy was evaluated by transrectal ultrasonography on alternate days. Significantly (P less than 0.05) more mares given 1.5 or 2.25 g of progesterone (6 of 8 and 4 of 5 mares, respectively), but not those given 0.75 g (3 of 7 mares), maintained pregnancy through day 32, compared with control mares (0 of 6). Progesterone concentrations decreased significantly (P less than 0.025) in all groups after administration of prostaglandin F2 alpha at day 14, and significant (P less than 0.05) effects of time and treatment on progesterone concentrations were found between days 12 and 22, and 22 and 32. Although treatment with 1.5-g and 2.25-g doses of microencapsulated progesterone improved maintenance of pregnancy, compared with that of vehicle-treated controls, administration of 2.25 g of microencapsulated progesterone appeared to be most efficacious in maintenance of pregnancy during the study interval.