Structure and functions of the placenta in common minke (Balaenoptera acutorostrata), Bryde's (B. brydei) and sei (B. borealis) whales.

The structure and functions of placentas were examined in 3 species of rorqual whales, common minke (Balaenoptera acutorostrata), Bryde's (B. brydei) and sei (B. borealis) whales, with the aim of confirming the structural characteristics of the chorion, including the presence of the areolar part, and clarifying steroidogenic activities and fetomaternal interactions in the placentas of these whales.

Areolae of the placenta in the Antarctic minke whale (Balaenoptera bonaerensis).

In this study, we examined the existence and structure of areolae and the steroidogenesis of areolar trophoblast cells in the Antarctic minke whale placenta morphologically and immunohistochemically. Placentas were collected from the 15th, 16th and 18th Japanese Whale Research Program under Special Permit in the Antarctic (JARPA) and 1st JARPA II organized by the Institute of Cetacean Research in Tokyo, Japan. The opening and cavity of fetal areolae formed by taller columnar trophoblast cells (areolar trophoblast cells) with long microvilli and a bright cytoplasm, as compared with the trophoblast cells of the chorionic villi interdigitating with the endometrial crypts, were recognized in observations of serial sections.

Structure and steroidogenesis of the placenta in the Antarctic minke whale (Balaenoptera bonaerensis).

There are few reports describing the structure and function of the whale placenta with the advance of pregnancy. In this study, therefore, the placenta and nonpregnant uterus of the Antarctic minke whale were observed morphologically and immunohistochemically. Placentas and nonpregnant uteri were collected from the 15th, 16th and 18th Japanese Whale Research Programme with Special Permit in the Antarctic (JARPA) and 1st JARPA II organized by the Institute of Cetacean Research in Tokyo, Japan.

Effects of semen extenders and storage temperatures on characteristics of frozen-thawed Bryde's (Balaenoptera edeni) whale spermatozoa.

The present study investigated effects of three semen extenders and storage temperatures on post-thaw characteristics of Bryde's whale spermatozoa. Spermatozoa were collected from the vasa deferens of three mature Bryde's whales captured during the Japanese whale research in the north-west Pacific (May to August 2007) after death. The three semen extenders used for freezing were 1) a commercialized synthetic extender (AndroMed: AM), 2) Tris-based + 10% bovine serum albumin (BSA) and 3) Tris-based + egg yolk (EY).

Follicle size-dependent changes in follicular fluid components and oocyte diameter in Antarctic minke whales (Balaenoptera bonaerensis).

The concentrations of various components of follicular fluid were compared among three groups of follicles (small, <5 mm; medium: 5-10 mm; large, >10 mm) with a control that consisted of the components of umbilical serum using seven pregnant Antarctic minke whales. Follicular oocytes recovered from the follicles were also used for measurement of oocyte diameter after removing the cumulus cells. The mean diameter of the ooplasm in the oocytes from the large follicles (143.

Attempt at intracytoplasmic sperm injection of in vitro matured oocytes in common minke whales (Balaenoptera acutorostrata) captured during the Kushiro Coast Survey.

The present study was conducted during the Kushiro Coast Survey in an attempt to produce common minke whale embryos. In Experiment 1, we attempted to determine the appropriate culture duration (30 or 40 h) for in vitro maturation (IVM) of immature oocytes using the Well of the Well method. In Experiment 2, and intracytoplasmic sperm injection (ICSI) was applied to matured oocytes from prepubertal and adult common minke whales after IVM culture (40 or 48 h), and then their embryonic development was assessed.

Developmental capacity of Antarctic minke whale ( Balaenoptera bonaerensis ) vitrified oocytes following in vitro maturation, and parthenogenetic activation or intracytoplasmic sperm injection.

The present study investigated the effects of the sexual maturity of oocyte donors on in vitro maturation (IVM) and the parthenogenetic developmental capacity of fresh minke whale oocytes. The effects of cytochalasin B (CB) pretreatment and two types of cryoprotectant solutions (ethylene glycol (EG) or ethylene glycol and dimethylsulfoxide (EG + DMSO)) on the in vitro maturation of vitrified immature whale oocytes were compared, and the developmental capacity of vitrified immature whale oocytes following IVM and intracytoplasmic sperm injection examined (ICSI). The maturation rate did not differ significantly with sexual maturity (adult, 60.

Effects of cryodevice type and donors' sexual maturity on vitrification of minke whale (Balaenoptera bonaerensis) oocytes at germinal vesicle stage.

Germinal-vesicle-stage oocytes enclosed with compact cumulus cell layers (COCs) were recovered from adult or prepubertal minke whale ovaries, and were vitrified in a solution containing 15% ethylene glycol, 15% DMSO and 0.5 M sucrose using either a Cryotop or an open-pulled straw (OPS) as the cryodevice. The post-warm COCs with normal morphology were cultured for 40 h in a 390 mosmol in vitro maturation medium, and oocytes extruding the first polar body were considered to be matured.

Attempt at in vitro maturation of minke whale (Balaenoptera Bonaerensis) oocytes using a portable CO2 incubator.

The present study was conducted to investigate whether a portable CO2 incubator was effective for in vitro maturation (IVM) of bovine, porcine and minke whale oocytes, and the effect of maturation media supplemented with different hormones; porcine follicle stimulating hormone (pFSH), estradiol-17beta (E2), or pregnant mare's serum gonadotropin (PMSG): human chorionic gonadotropin (hCG) for minke whale immature oocytes was also examined. In vitro maturation rates of bovine and porcine oocytes cultured in the portable CO2 incubator were not significantly different from the standard CO2 incubator. In minke whale IVM culture using the portable incubator, the maximum expansion of cumulus mass was observed by pFSH/E2 and PMSG/hCG at the end of IVM culture.

Comparative studies on lipid analysis and ultrastructure in porcine and southern minke whale (Balaenoptera bonaerensis) oocytes.

The present study was conducted to clarify the difference in the color of the cytoplasm in immature follicular oocytes from prepubertal and adult minke whales. The four lipid contents (triglyceride, total cholesterol, phospholipids and non-esterified fatty acids) in vitrified immature oocytes from prepubertal and adult minke whales, and also in fresh and vitrified immature porcine oocytes, were measured. The lipid contents in vitrified-warmed minke whale oocytes were similarly high compared with those in vitrified-warmed porcine oocytes.

Relationship between the appearance of preantral follicles in the fetal ovary of Antarctic minke whales (Balaenoptera bonaerensis) and hormone concentrations in the fetal heart, umbilical cord and maternal blood.

The present study aimed to determine the relationship among changes in the number of preantral follicles and concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), progesterone (P4), androstenedione (A) and estradiol-17beta (E2) in the fetal heart, umbilical cord and maternal blood. Primordial follicles had already appeared in a 20 cm fetus and primary follicles were observed in a 50 cm fetus. In a 70 cm fetus, the number of primordial and primary follicles increased rapidly and secondary follicles were present.

Relationship between serum sex hormone concentrations and histology of seminiferous tubules of captured baleen whales in the Western North Pacific during the feeding season.

The present study was conducted to obtain new information on relationships among serum testosterone (T), estradiol-17 beta (E(2)), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) concentrations and histology of seminiferous tubules in captured common minke and Bryde's whales during the feeding season. Blood samples and testes were collected from common minke (n=39 for blood samples, n=15 for testes) and Bryde's (n=14 for blood samples, n=7 for testes) whales captured from May 2001 to August 2001 in the Western North Pacific. Serum T concentrations, in 35.

The pattern of ovarian development in the prepubertal antarctic minke whale (Balaenoptera bonaerensis).

This study describes the morphological and morphometrical changes associated with prepubertal ovarian development in the Antarctic minke whale (Balaenoptera bonaerensis). Ovaries were harvested from 94 immature minke whales caught in the Antarctic Ocean during the summer feeding season (December-March). Notable differences in ovarian size and morphology were found among animals.