Reproduction

doi: 10.1530/jrf.0.0170001-apmid: N/A

The Editor of the Society's Proceedings wishes to draw attention to the following correction:J. Reprod. Fert. (1968) 16, 319The title of Dr Doreen Tampion's paper should read `The effect of the medium on the swimming performance of bull spermatozoa'.

ACKERMAN, D. R.; SOD-MORIAH, U. A.

doi: 10.1530/jrf.0.0170001pmid: 5697440

Summary.Glycerolated semen specimens of several donors were examined for DNA content after refrigeration at +6° C for 7 days, and after storage in liquid nitrogen for periods ranging from 2 to 75 weeks. Fresh specimens were also studied. DNA determinations were made in each case by both Feulgen microspectrophotometry (in arbitrary units) and by the Webb-Levy chemical determination. The quantity of DNA per cell in arbitrary units and in mg × 10−9 remained constant after refrigeration, and after freezing-preservation for all time periods studied. Discrepancies between the two kinds of determination, and the concept of embryonic mortality due to aged spermatozoa are discussed.

ELLIOTT, D. S.; LEGATES, J. E.; ULBERG, L. C.

doi: 10.1530/jrf.0.0170009pmid: 5697453

Summary.Low fertility in mice selected for small body size (L) at 6 weeks of age was due to fewer matings, more ovulation failures in females mating, a lower ovulation rate and a lower fertilization rate than in unselected mice (C2) maintained as a control. The L males apparently had less libido than C2 males. This may have contributed to fewer matings in the L line. Failure to mate or failure to ovulate, if mating, could not be explained by differences in age or in body weight. It is suggested that a thyroid deficiency was responsible.Females of the line selected for large body size (H) at 6 weeks of age ovulated more ova than C2 females. Essentially no foetal death occurred, after implantation, except in the H line. A lower percentage of the foetuses was living at 18 days of gestation in females of this line than in the females of the C2 line.

BLACKWOOD, CARLTON E.; HOSANNAH, YVONNE; MANDL, INES

doi: 10.1530/jrf.0.0170019pmid: 5697439

Summary.The developmental progression of two endopeptidases, four exopeptidases, trypsin inhibitors and chymotrypsin inhibitors in rat embryos from fertilization to the fully formed foetus and beyond has been evaluated. Biochemical and histochemical procedures using the same chromogenic substrates were applied to study uteri at various stages of gestation, embryos from the 11 th day of gestation to term, and kidney, liver and spleen from the 18th day of gestation to the adult stage. Activities were found to be lower in isolated embryos than in pregnant uteri but rates of increase were comparable except in the case of cystinedi-β-naphthylamidase which showed a greater rate of increase in uteri. Enzyme activities in liver, kidney and spleen were relatively high during the late stages of gestation, decreased at birth and increased again in postnatal tissues. The rate of change as well as the absolute values differed for each enzyme as well as for each tissue. There is evidence that soluble enzymes assayed by biochemical techniques are synthesized before particle-bound enzymes measured by histochemical techniques. Electrophoretic mobility, metal ion requirements and enzyme localization indicate that several closely related but distinct enzymes take part in foetal development.

QUINN, P. J.

doi: 10.1530/jrf.0.0170035pmid: 5748741

Summary.The methyl green assay method has been used to determine the activity of DNase I and DNase II in ram, bull, human, dog and rabbit seminal plasma. The activity of DNase II was higher except in the ram. The DNase I activity of ram seminal plasma was inhibited by low concentrations of citrate, zinc and cetyltrimethylammonium bromide ; this detergent also caused a reduction of DNase II activity. There was a stimulation of DNase I activity by 10 mm-citrate but not by concentrations less than 2 mm. Addition of antibiotics or shaking of ram seminal plasma with toluene did not affect the activity of either DNase. After deep freezing of ram semen there was a decrease of DNase I activity in the plasma and an increase of DNase I and II activity in extracts obtained from disintegrated spermatozoa. No significant change in DNase activity could be detected in the plasma of ram semen which had previously been subjected to cold shock.

KLAUSING, MARTHA N.; MEYER, ROLAND K.

doi: 10.1530/jrf.0.0170041pmid: 5697447

Summary.The ovulating hormone (oh) of the pituitary gland was determined in untreated, 30-day-old immature female rats given an ovulating dose of pregnant mare's serum gonadotrophin (pmsg), and in pmsg-primed rats given sodium phenobarbital (PB) before the critical period (13.30 hours) or after the critical period (16.30 hours) on Day 32. PB given at 13.30 hours blocks ovulation for 24 hr. The adenohypophysis was removed at various times from 14.00 hours on Day 32 to 07.30 hours on Day 35 and assayed for oh in 24-day-old pmsg-PB treated test rats. The number of ova ovulated by the test rats indicated the pituitary oh. In untreated animals the pituitary oh remained high. In the pmsg-primed rats, the hormone decreased during the critical period, 14.00 to 16.00 hours on Day 32, but was minimal on the morning of Day 33 and remained low through Day 35. In pmsg-treated animals injected with PB at 13.30 hours on Day 32, the oh changes were delayed for 24 hr. When PB was administered at 16.30 hours, oh decreased during the critical period on Day 32 but minimal oh on Day 33 was not as low as in the pmsg-primed rats at the same time. Instead of remaining low the hormone increased by 16.00 hours on Day 33. In ten of twelve test situations between 14.00 and 16.00 hours each day there was an oh decrease, indicating a diurnal oh secretion.

BEDFORD, J. M.; HUNTER, R. H. F.

doi: 10.1530/jrf.0.0170049pmid: 5697448

Summary.Exposure of rabbit semen to X-irradiation did not reduce the fertilization rate until doses of >25,000 r were used, although motility was noticeably affected at 15,000 r. Evidence of a depressant effect of much lower doses of X-irradiation on the fertilizing ability of rabbit spermatozoa was obtained, however, by using a more sensitive system in which irradiated aliquots from an ejaculate were inseminated mixed together with an exactly equivalent volume of untreated semen from the same ejaculate. Under these competitive conditions the fertilizing ability of spermatozoa was found not to be affected by a dose of 10,000 r, but was significantly depressed (P<0·01) by 15,000 r, as judged by an increase in the proportion of normally developing to retarded ova, recovered 50 hr after an ovulation injection of hcg. It appears that this depressant effect is exerted at the site of fertilization rather than on sperm transport.X-irradiation of spermatozoa did not increase polyspermic or delayed fertilization, neither did irradiation have any significant effect on the formation of the male pronucleus. A dose response effect was seen at the time of the first cleavage division, for at 24 hr the cleavage rate of control ova (68·5%) was similar to that of ova fertilized by spermatozoa treated with 10,000 r (68%), but only 33% of ova fertilized by spermatozoa treated with 20,000 to 25,000 r had cleaved at this time compared with 78% of their controls. At 29 and 50 hr several ova fertilized by irradiated spermatozoa remained at the pronuclear stage or at metaphase of the first cleavage division, and even at 50 hr the great majority had only reached the 2-cell stage. Thus, although it is known that cleavage can occur in the absence of the male elements, the first cleavage division does not appear to follow activation of the egg automatically and independently since it has been shown that the state of the male elements introduced at fertilization can influence the rate and ultimate success of the changes which take place at this time.

HIRT, B. J.; GIER, H. T.; MARION, G. B.

doi: 10.1530/jrf.0.0170059pmid: 5697449

Summary.Adult white mice were maintained on a proven laboratory chow to parturition, then on experimental feed for 20 days; young were weaned, placed on full feed, and mated at 60 days.Casein, constituting 12, 10, 8 and 6% of an otherwise balanced food, resulted in survival of young to 20 days of 82, 69, 38 and 4% of those born. Corn oil reduced from 10% for controls to 2·5%, with 10% casein, resulted in 43% survival. Whole grain corn meal (9% protein) was adequate for normal survival, but corn meal diluted with corn starch 2 :1 maintained only 35% of the young to 20 days. Individual weight and litter weight was reduced comparably. Young from litters, in which less than half survived, recovered slowly, failed to reproduce until after 120 days of age (50% produced a litter by 150 days) and suffered loss of 40 to 60% of their young. The survivors of these litters were approximately 20 days older than controls before they reproduced (average 114 days of age) but maintained nearly 90% of their young to weaning.Litters reduced to five on the day of birth were maintained to 20 days even on 8% casein and 2·5% fat, and all young matured normally.Severe deficiencies of either fat or protein in the food of a lactating female resulted in reduced weight and number of young. Survivors were slow in maturing and produced small litters, with high mortality, through the second generation.

FINN, C. A.

doi: 10.1530/jrf.0.0170069pmid: 5697450

Summary.When unilaterally ovariectomized mice were mated, the horn containing blastocysts increased in length during the early stages of implantation, at the same time as the onset of the Pontamine Sky Blue reaction and before implantation swellings were visible macroscopically. Similarly, the horns of pseudopregnant entire mice injected with oil to induce a decidual cell reaction were longer than the uninjected horns when the response had reached the stage at which a Pontamine Sky Blue reaction could be elicited. It is concluded that growth in length of the uterus occurs during the implantation reaction and this may assist in the accommodation of blastocysts along the length of the uterus.

FOX, K. A.

doi: 10.1530/jrf.0.0170075pmid: 5748742

Summary.Male albino and wild house mice were reared from weaning (at 21 days) either to 37 or 56 days of age in: (1) isolation, (2) all-male groups of four, or (3) all-male groups of four in cohabitation with an adult female. At 37 days the cohabiting albino males exhibited larger testes and epididymides than animals in the other two situations. Similarly, they had larger seminiferous tubules and were significantly more mature (by an arbitrary rating system) than the isolated males or the males in all-male groups. Wild males reared in isolation or in cohabitation were reproductively superior in essentially the same fashion to males in all-male groups. Cohabiting wild males, however, were significantly more mature than wild males in either of the other two conditions.When reared to 56 days, albino males in cohabitation exhibited a high degree of social conflict and were reproductively inferior to both the isolates and the males in all-male groups. In contrast, cohabiting wild males at 56 days of age showed reproductive growth equal to that of males in all-male groups. However, both albino and wild adult males in cohabitation exhibited none of the reproductive advantages seen in 37-day-old cohabiting males.In a final set of studies it was shown that albino males reared to 37 days of age with intact females had larger testes, epididymides and seminiferous tubules and significantly higher concentrations of epididymal spermatozoa than male litter-mates reared with ovariectomized females. Wild males reared with intact females, while failing to show larger testicular and epididymal weights, did possess larger seminiferous tubules than wild males with ovariectomized females.Those studies show that the presence of an intact female bestows reproductive advantages upon groups of young male mice. These advantages do not persist to adulthood.