Reproduction

Yoshida, M.; Ishizaki, Y.; Kawagishi, H.

doi: 10.1530/jrf.0.0880001pmid: 2313628

Summary. Follicular oocytes collected from prepubertal gilts at a local slaughter house were matured (36 h), fertilized and developed in vitro. Of 785 embryos, 190 (24%) embryos cleaved to the 2–4-cell stages with blastomeres of regular size by 33 h after insemination. These cleaved embryos were surgically transferred into the oviducts of 4 synchronized recipient gilts and recovered from the uterine horns 4 or 7 days later: 13 morulae, 2 blastocysts and 1 expanded blastocyst were recovered after 4 days and 3 hatched blastocysts were recovered 7 days after transfer. Re-culture in vitro sustained further development of morulae recovered 4 days after transfer: 11 of 13 morulae had developed to the blastocyst/hatched blastocyst stages. Overall, 17 of 190 (9%) embryos developed to the blastocyst stage. The results indicate that pig oocytes can be matured and fertilized in vitro, and subsequently develop to the blastocyst stage.Keywords: maturation; in vitro; fertilization; oocyte; blastocyst; pig

Bambra, C. S.; Tarara, R.

doi: 10.1530/jrf.0.0880009pmid: 2313657

Summary. An immunohistochemical technique using a high specificity antiserum against baboon CG was used to demonstrate the presence of a CG-like material on: (1) fixed baboon placental sections collected between 31 and 39 days of gestation, (2) trophoblast monolayers derived from hatched embryos grown in vitro for 15 days and (3) trophoblast cells derived from cells dispersed from placentae collected between Days 31 and 39 of pregnancy. A specific radioimmunoassay was used to detect concentrations of baboon CG in daily spent medium. Immunohistochemical studies showed that material cross-reacting with CG was present on all the three sources of trophoblast. The embryos secreted CG from attachment onwards and immunoactive CG was measurable in daily spent medium collected from placenta-derived trophoblast cultures. It is concluded that baboon CG is localized in the syncytiotrophoblast of fixed placental sections and cellular trophoblast derived from cultured embryos and placental cells.Keywords: baboon; trophoblast; chorionic gonadotrophin; immunochemistry

Breed, W. G.

doi: 10.1530/jrf.0.0880017pmid: 2313635

Summary. Hopping mice were examined to study two interrelated questions: (1) when groups of adults of both sexes are kept together in one cage in the laboratory is there evidence that the females copulate with only one male, and (2) is a copulatory plug formed in the female tract after ejaculation? The findings indicate that a female will sometimes lock with more than one male in the group during an oestrous period induced by administration of exogenous gonadotrophins, and that a small 'plug' of soft material forms post coitum in the more caudal parts of the female tract. Individuals of this species, therefore, do not appear to be strictly monogamous, at least in this artificial laboratory situation. Although a coagulum is formed, this is quite different from the typical hard copulatory plug that occurs in common laboratory murids; it may possibly reduce sperm backflow from the lower region of the female reproductive tract.Keywords: hopping mouse; copulation; plug

Ravindranath, N.; Moudgal, N. R.

doi: 10.1530/jrf.0.0880025pmid: 2107302

Summary. Female bonnet monkeys were injected i.v. with 25 μl antiserum to FSH on Days 5, 6 or 7 of the cycle: the length of the luteal phase was shortened but there was no alteration in cycle length. Proven fertile females (N = 6) were caged throughout the period of the experiment (6 cycles) with proven fertile males and treated with 25 μl FSH antiserum on Day 7 of each of 3 successive cycles. Out of 18 cycle exposures during the treatment phase, 17 were ovulatory, but no pregnancies occurred. In the post-treatment phase, 5 monkeys became pregnant within 3 cycle exposures. These results show that it is possible to render female monkeys infertile by creating luteal insufficiency and this can be achieved repeatedly in a reproducible manner by depriving the cyclic females of FSH support on Day 7 of consecutive cycles.Keywords: monkey; ovary; follicular phase; luteal phase defect; pregnancy

McRae, Ann C.; Church, R. B.

doi: 10.1530/jrf.0.0880031pmid: 2313645

Summary. A scoring scheme was devised to characterize visually the morphological differentiation of whole-mount, unfixed mouse blastocysts. Embryos were recovered from groups of intact mice (implanting embryos) and mice ovariectomized on Day 3 of pregnancy (implantation-delayed embryos) every 3 h from 18:00 h on Day 4 until 12:00 h on Day 5. Blastocyst differentiation was assessed according to the presence of a zona pellucida, the appearance of the outer margin of trophectoderm cells, the visibility of the blastocoele and the relative size of the inner cell mass. The results obtained indicate that, during this period, implanting and implantation-delayed mouse blastocysts lose the zona as well as exhibit rounded trophectoderm cells, an enlarged inner cell mass and an increasing opacity of the blastocoele. In contrast, the trophectoderm cells of implanting blastocysts only exhibit extensive cytoplasmic projections, probably due to remodelling of the intracellular cytoskeleton. Growth of the inner cell mass appeared to precede the other morphological changes in the majority of blastocysts, and thus might be a prerequisite for further differentiation. The rate of blastocyst differentiation and the survival of embryos were adversely affected by the condition of delayed implantation, induced by ovariectomy. This study suggests that the appearance of cytoplasmic projections from trophectoderm cells is central to the control of blastocyst implantation.Keywords: blastocyst; morphology; trophectoderm; implantation; mouse

von Deimling, O.; Wassmer, B.

doi: 10.1530/jrf.0.0880041pmid: 2313652

Summary. Twenty-five (25) electrophoretic bands with esterase activity were distinguished in supernatants of cauda epididymidis of DBA/2J mice. Twenty (20) of these were assigned to 10 genetically defined esterases (ES-1, ES-2, ES-3, ES-6, ES-7, ES-11, ES-14, ES-17, ES-19, ES-22) which were already known from investigations of other mouse tissues. Furthermore, ES-10 was identified in cauda supernatants after isoelectric focussing. A hitherto genetically undefined esterase was assigned to locus Es-28 which was expressed solely in the epididymis. Three phenotypes were distinguished: ES-28A was present in the majority of the inbred strains examined, ES-28B was observed in AKR/Han mice and ES-28C was found in SEG/1 mice.Keywords: esterase; mouse; cauda epididymidis

Huang, H. F. S.; Marshall, G. R.; Nieschlag, E.

doi: 10.1530/jrf.0.0880051pmid: 2313653

Summary. Morphometric study revealed that, at 40 days after the start of vitamin A replacement, A1 spermatogonia and preleptotene spermatocytes appeared in more than 70% of the whole mounts of seminiferous tubules of vitamin A-deficient rats. By 42 days, the appearance of these cell types was reduced by 50%, and A2 and A3 spermatogonia were predominant. By 46 days, A1–A3 spermatogonia appeared in <30% of the tubular length while A4, intermediate and B spermatogonia became the major cell types in the basement compartment of seminiferous tubules. The predominance of spermatogonia noted at given times was corroborated by higher frequencies of tubular cross-sections of stages in which that particular type of spermatogonium resides. These results indicate that seminiferous tubules of vitamin A-replaced–vitamin A-deficient rats are 'enriched' for particular stages. Tracing the development of [3H]thymidine-labelled preleptotene spermatocytes revealed normal kinetics of germ cell differentiation in these animals. Furthermore, the spermatogonial proliferations in the vitamin A-replaced–vitamin A-deficient rats were quantitatively normal. We suggest that vitamin A replacement may result in temporal suppression of the differentiation of A2–B spermatogonia, leading to a stimulation or synchronization of certain groups of undifferentiating spermatogonia which undergo active proliferation simultaneously. These synchronized populations of spermatogonia continue to proliferate and differentiate, thus resulting in the stage-enrichments noted at later times.Keywords: vitamin A deficiency; spermatogenesis; seminiferous epithelium; stage enrichment; rat

Farin, C. E.; Nett, T. M.; Niswender, G. D.

doi: 10.1530/jrf.0.0880061pmid: 2313654

Summary. To examine the effect of purified LH on development and function of luteal cells, 27 ewes were assigned to: (1) hypophysectomy plus 2 μg ovine LH given i.v. at 4-h intervals from Days 5 to 12 of the oestrous cycle (oestrus = Day 0; Group H + LH; N = 7); (2) hypophysectomy with no LH replacement (Group N–LH; N = 6); (3) control (no hypophysectomy) plus LH replacement as in Group H + LH (Group S + LH; N = 7); (4) control with no LH treatment (Group S–LH; N = 7). Blood samples were collected at 4-h intervals throughout the experiment to monitor circulating concentrations of LH, cortisol and progesterone. On Day 12 of the oestrous cycle corpora lutea were collected and luteal progesterone concentrations, unoccupied receptors for LH and number and sizes of steroidogenic and non-steroidogenic luteal cell types were determined. Corpora lutea from ewes in Group H–LH were significantly smaller (P < 0·05), had lower concentrations of progesterone, fewer LH receptors, fewer small luteal cells and fewer non-steroidogenic cells than did corpora lutea from ewes in Group S–LH. The number of large luteal cells was unaffected by hypophysectomy, but the sizes of large luteal cells, small luteal cells and fibroblasts were reduced. LH replacement in hypophysectomized ewes maintained luteal weight and the numbers of small steroidogenic and non-steroidogenic luteal cells at levels intermediate between those observed in ewes in Groups L–LH and S–LH. In Group H + LH ewes, luteal and serum concentrations of progesterone, numbers of luteal receptors for LH, and the sizes of all types of luteal cells were maintained. Numbers of small steroidogenic and non-steroidogenic cells were also increased by LH in hypophysectomized ewes.In Exp. II, 14 ewes were assigned to: (1) sham hypophysectomy with no LH replacement therapy (Group S–LH; N = 5); (2) sham hypophysectomy with 40 μg ovine LH given i.v. at 4-h intervals from Day 5 to Day 12 of the oestrous cycle (Group S + LH; N = 5); and (3) hypophysectomy plus LH replacement therapy (Group H + LH; N = 4). Experimental procedures were similar to those described for Exp. I. Treatment of hypophysectomized ewes with a larger dose of LH maintained luteal weight, serum and luteal progesterone concentrations and the numbers of steroidogenic and non-steroidogenic luteal cells at control levels. Based on the results of the two experiments it is concluded that: (1) LH has important trophic actions for steroidogenic and non-steroidogenic luteal cells; and (2) LH appears to be the only pituitary gonadotrophin required to maintain luteal function in ewes hypophysectomized during the oestrous cycle.Keywords: sheep; LH; luteal cells

Zhu, Z.; Deng, H.; Fenderson, B. A.; Nudelman, E. D.; Tsui, Z.

doi: 10.1530/jrf.0.0880071pmid: 2313655

Summary. The glycolipid composition of human myometrium and endometrium was examined at various stages of maturation and reproduction. The major neutral glycolipids of both myometrium and endometrium were identified by high-performance thin-layer chromatography as globo-series glycolipids, Gb3 and Gb4. The major acidic glycolipids (gangliosides) were identified similarly as GM3 and GD3, with lesser amounts of GM1, GD1a, and GT1b. During pregnancy, GD3 expression declined in both myometrium and endometrium, whereas GM3 expression increased. Reciprocal changes in GM3/GD3 expression were mirrored by appropriate changes in the glycosyltransferases required for their synthesis; α2→3sialyltransferase activity increased approximately 3-fold during pregnancy, while α2→8sialyltransferase activity declined to about 20%. The results focus attention on the glycolipids of uterine tissues, their regulation, and their possible role in reproduction and fertility.Keywords: myometrium; endometrium; glycolipids; pregnancy; human

Taggart, D. A.; Temple-Smith, P. D.

doi: 10.1530/jrf.0.0880081pmid: 2313656

Summary. Changes in the number and distribution of spermatozoa in the epididymis of the adult brown marsupial mouse were examined during July/August in mated and unmated males. The effects of mating on epididymal sperm populations were studied in 2 groups of males each mated 3 times and compared with the number and distribution of spermatozoa in the epididymides of 4 unmated control groups. One testis and epididymis were removed from each animal (hemicastration) either before or early in the mating season to provide information on initial sperm content and distribution. The contralateral side was removed later in the mating season to examine the effects of mating or sexual abstinence on epididymal sperm distribution.Epididymal sperm number peaked in both the distal caput and distal corpus/proximal cauda epididymidis in late July. The total number of spermatozoa, including those remaining in the testis, available to each male at the beginning of the mating season in early August was ∼4·4 × 106/side. Although recruitment of spermatozoa into the epididymis from the testis continued until mid-August, sperm content of the epididymis reached a peak of about 3·5 × 106/epididymis in early August. At this time approximately 0·9 × 106 spermatozoa remained in the testis which had ceased spermatogenic activity. Throughout the mating season, epididymal spermatozoa were concentrated in the distal corpus/proximal cauda regions of the epididymis and were replenished by spermatozoa from upper regions of the duct. Relatively few spermatozoa were found in the distal cauda epididymidis, confirming a low sperm storage capacity in this region.A constant loss of spermatozoa from the epididymis, probably via spermatorrhoea, occurred throughout the mating season and very few spermatozoa remained in unmated males in late August before the annual male die-off. Mating studies showed that an average of 0·23 × 106 spermatozoa/epididymis were delivered per mating in this species, but the number of spermatozoa released at each ejaculation may be as few as 0·04 × 106/epididymis when sperm loss via spermatorrhoea is taken into account.We suggest that the unusual structure of the cauda epididymidis, which has a very restricted sperm storage capacity, may function to limit the numbers of spermatozoa available at each ejaculation and thus conserve the dwindling epididymal sperm reserves in order to maximize the number of successful matings which are possible during the mating season.Keywords: epididymis; spermatozoa; sperm storage; mating; marsupial; dasyurid