Biological effects of trilostane in vitro on oocyte maturation and fertilization in the hamster

Summary The effects of the inhibition of steroidogenesis by trilostane on oocyte maturation were examined by studying spontaneous maturation and fertilization in vitro. 10^–6 M trilostane had no influence on the meiotic process, whether the oocytes were naked or not. At a concentration of 10^–6 M and 10^–7 M trilostane, low normal pronuclear formation and high polyspermy were found during in vitro fertilization. However, no retarded male pronuclear development could be detected in the trilostane-treated group. Thus, steroid producing activity within ova is apparently necessary to prevent multiple sperm penetration, but it has no effect on meiosis or the action of the so-called male pronucleus growth factor (MPGF).     

Cooperative inhibitory effect of follicular fluid and cAMP on hamster oocyte maturation

Summary Porcine or human follicular fluid inhibited the spontaneous maturation of isolated hamster oocytes in vitro during the first 1.5 h of culture. Moreover, the presence of 50% follicular fluid combined with 100 M dbcAMP cooperatively reduced the incidence of germinal vesicle breakdown. The addition of FSH also inhibited the resumption of meiosis, and the presence of LH did not overcome the inhibitory effects of follicular fluid and tended to impede isolated hamster oocyte maturation in vitro.     

Cooperative inhibitory effect of follicular fluid and cAMP on hamster oocyte maturation

Porcine or human follicular fluid inhibited the spontaneous maturation of isolated hamster oocytes in vitro during the first 1.5 h of culture. Moreover, the presence of 50% follicular fluid combined with 100 microM dbcAMP cooperatively reduced the incidence of germinal vesicle breakdown. The addition of FSH also inhibited the resumption of meiosis, and the presence of LH did not overcome the inhibitory effects of follicular fluid and tended to impede isolated hamster oocyte maturation in vitro.     

Infertility of the hamster oocyte having matured in vitro]

The comparative study of fertilization, with the same sperm sample, of in vitro matured oocytes and freshly ovulated ones, shows a new aspect of mammalian oocyte maturation. While 80% of freshly ovulated oocytes are fertilized, in vitro matured eggs are not fertilizable. They present the ability to be penetrated by spermatozoa 4 to 6 hrs. only after HCG injection. This is therefore not on tubal influence but depends on an oocyte specific factor which appears during the end of intrafollicular maturation.     

In vitro fertilization of mouse and hamster eggs after freezing and thawing

Summary Mouse eggs (12–14%) and hamster eggs (87–94%) appear normal upon thawing after having been stored for 30 min to 25 h at –70°C and –196°C. While 89–98% of the normal appearing hamster eggs are capable of fertilization in vitro, only 4–13% of the mouse eggs can be fertilized. The ability of fertilized eggs to develop in culture and their viability upon transfer to pseudopregnant recipients is under investigation.This work was supported by grants from the U.S. Public Health Service and the Ford Foundation. Sincere thanks are due to Prof.Y. Nishikawa of Kyoto University, Japan, for advice and to Mrs.Rose Bartke and Ms.D. M. Hunt for assistance.     

Quantitative studies on in vitro transformation of hamster chondrocytes

Summary Hamster chondrocytes could be transformed in a quantitative assay system which used X-irradiated feeder layer cells. Morphological transformation occurred on addition of, 4NQO, but not in control cultures. Differentiation was classified into 3 types (good, poor and none); normal and transformed colonies contained similar proportions of the 3 types.This work was supported by a grant from the Ministry of Education, Science and Culture, Japan.We thank Miss M. Tanaka for her technical assistance.     

Scanning electron microscopy of golden hamster spermatozoa before and during fertilization

Résumé L'observation directe de la surface du sperme et de l'uf au microscope électronique «scanning» a montré une série de changements dans le spermatozoïde du Hamster doré avant la fertilisation ainsi que la relation topographique entre le spermatosoïde et l'uf au moment de la fertilisation. Il semble que les microvilli de l'uf participent activement à l'incorporation de la tête du sperme dans le cytoplasme de l'uf.     

Oocyte maturation in vitro: Contribution of the oviduct to total maturation inXenopus laevis

Summary Contact of progesterone matured oocytes ofXenopus laevis with the oviduct reduces the time necessary to attain cleavage capacity from 24 h to 3 h. Full maturity has been demonstrated by normal development of the matured eggs after fertilization.     

Quantitative studies on in vitro transformation of hamster chondrocytes.

Hamster chondrocytes could be transformed in a quantitative assay system which used X-irradiated feeder layer cells. Morphological transformation occurred on addition of, 4NQO, but not in control cultures. Differentiation was classified into 3 types (good, poor and none); normal and transformed colonies contained similar proportions of the 3 types.     

Oocyte maturation in vitro: contribution of the oviduct to total maturation in Xenopus laevis.

Contact of progesterone matured oocytes of Xenopus laevis with the oviduct reduces the time necessary to attain cleavage capacity from 24 h to 3 h. Full maturity has been demonstrated by normal development of the matured eggs after fertilization.     

In vitro fertilization of the mongolian gerbil egg

Zusammenfassung Ova von mongolischen WüstenmäusenMeriones unguiculatus (Gerbillinae) wurden mit Spermatozoa aus der Epididymis in Follikelflüssigkeit von Kühen zusammengebracht. Es konnte gezeigt werden, dass die Spermatozoen während der Inkubation in diesem Medium die Fähigkeit erlangen, in die Ova einzudringen.     

Isoforms of soluble alpha-tubulin in oocytes and brain of the frog (genus Rana): changes during oocyte maturation

Rana oocytes have previously been shown to contain much more soluble tubulin than does the brain, suggesting different assembly and disassembly dynamics of frog oocyte tubulin compared to that in brain. By using centrifugation, SDS-PAGE, two-dimensional gel electrophoresis and Western blots, probed with anti-α-tubulin monoclonal antibodies, polymorphic α-tubulins (isoforms) were compared in brains and follicle-enclosed oocytes of northern (Rana pipiens) and southern (R. berlandieri) frogs. Oocyte tubulin in both species had isoforms with greater ranges of isoelectric point (pI) than those of brain tubulins; in particular, the oocyte tubulin pIs ranged further into the acidic region of the isoelectric-focusing gels than corresponding brain tubulin. This difference may, in part, be responsible for the previously reported assembly differences between oocyte tubulin (undetectable assembly) and brain tubulin (high assembly). Isoforms of α-tubulin with relat ively acidic pI were more abundant in northern frog brain and oocyte soluble extracts than in analogous extracts from southern frogs. Furthermore, additional acidic α-tubulin isoforms were found in progesterone-treated oocytes (i.e., eggs), indicating increased heterogeneity of acidic a-tubulin isoforms during oocyte meiotic maturation. Among northern frog oocyte soluble components fractionated on Superose-6b columns, tubulin complexes with apparent molecular mass of about 1800 kDa were found to contain acidic α-tubulin isoforms while the putative oligomeric tubulins with an apparent molecular mass of about 250 kDa contained an additional relatively basic α-tubulin isoform. The acidic α-tubulin isoforms, therefore, are proposed to be associated with cold-adaptable cells of brain and oocytes, and may also be involved in stabilization of large soluble tubulin complexes in oocytes of the northern frog. Received 1 October 2002; accepted 9 October 2002 RID="*" ID="*"Corresponding author.