Reproduction

TACHÉ, YVETTE; TACHÉ, J.; SELYE, H.

doi: 10.1530/jrf.0.0370257pmid: 4856831

Summary.In rats, CS-1 (5 mg) totally prevents implantation when administered by mouth during the first 8 days post coitum, but has no influence on pregnancy if treatment is initiated after the 13th day of gestation. The antifertility effect of this compound is abolished by the simultaneous injection of progesterone or prolactin. CS-1 might depress the production of pituitary luteotrophic hormone, thereby interfering with the secretory function of the corpus luteum and diminishing the supply of progesterone below the level required to maintain pregnancy.

SOD-MORIAH, U. A.; GOLDBERG, G. M.; BEDRAK, E.

doi: 10.1530/jrf.0.0370263pmid: 4852545

Summary.Heat-acclimatized rats were exposed to an ambient temperature of 35°C, and the effect on testicular histology, reproductive capacity and body and scrotal temperature was evaluated. Both deep body and intrascrotal temperatures of these animals were found to be higher than those of control rats maintained at 22°C. The intrascrotal temperature in the heat-acclimatized animals and the deep body temperature in the controls were similar. Breeding experiments proved the heat-acclimatized animals to be capable of mating and reproducing, although at a lower rate than the controls. The heat reduced only the mating rate and fertilization. After conception, the groups showed no difference. Histological screening revealed degenerated seminiferous tubules randomly scattered in the testes of the heat-acclimatized rats although most of the tubules showed normal spermatogenesis. These localized necrotic foci resemble the overall appearance of a cross-section of a cryptorchid testis. The heat-acclimatized animals, however, maintain a body to scrotum temperature gradient which enables spermatogenesis to proceed despite the elevated temperatures.

VOMACHKA, A. J.; PAUP, D. C.; CONIGLIO, L. P.; McMANUS, M. J.; CLEMENS, L. G.

doi: 10.1530/jrf.0.0370269pmid: N/A

Summary.The synthetic progestins, norethynodrel and norethindrone, given neonatally to female hamsters caused masculinization of the genitalia, increased masculine sexual behaviour in the adults, and reduced spontaneous and hormone-induced female sexual behaviour. Neonatal progesterone treatment did not masculinize female hamsters but diminished hormone-induced feminine behaviour. Dydrogesterone neither masculinized nor defeminized female hamsters.

BYSKOV, ANNE GRETE S.

doi: 10.1530/jrf.0.0370277pmid: 4824695

Summary.Three stages of follicular atresia have been defined in the juvenile mouse ovary. Using autoradiography, the development and duration of the atretic process has been determined. The three stages of atresia represent consecutive stages in a single atretic process. A large follicle will incorporate [3H]thymidine into its granulosa cells: the labelling index of such a follicle is about 40%. As atresia sets in and progresses, the labelling index of the granulosa cells changes. This change was followed in autoradiographs prepared at different times after pulse labelling. Follicles in the early stages of atresia a day after label injection showed a higher labelling index than healthy follicles. This apparently paradoxical behaviour seems to result from a re-utilization of DNA freed by fragmented, pyknotic granulosa cells released into the follicular cavity. Labelling curves of follicles at different stages of atresia in relation to time were prepared. A comparison of such curves suggests that the time it takes a large follicle to become atretic is about 4 days.

GARRARD, G.; HARRISON, G. A.; WEINER, J. S.

doi: 10.1530/jrf.0.0370287pmid: 4824696

Summary.Details of the fertility of two inbred strains of mice, the reciprocal F1 hybrids between the strains and some F2 mice under temperate and high environmental temperature conditions are presented. Infertility was rare in the control mice but common in those exposed to heat. Genotypic differences were greater in the heat and chiefly of male origin, being related to the duration of exposure to the heat. Prolonged heat exposure caused an impairment of fertility which persisted even when the temperature stress was alleviated. There was some prolongation of the oestrous cycle at high temperatures but it was not closely related to the greatly reduced mating frequency which was the prime determinant of the failure to bear litters.The postimplantation and early postnatal mortality indicate a heterotic effect on survival. Prenatal mortality may have been greater in the mice exposed to heat than in the controls but the effect was too small to account for the environmental difference in the sizes of litters at birth. Mortality in the first 3 weeks of life was also greater in the heat where survival seemed to be a function of the inbred mother. The F2 litters had low mortality rates compared with inbred and F1 litters. Parental heterosis was apparent in both environments.The postnatal survival of litters was influenced by the litter's size at birth and its parity and the survival of individual animals was affected by the interval between birth and feeding and the body weight at birth. Both genotype and the temperature of the environment influenced the extent to which these variables operated.

TOULLET, FRANCINE; VOISIN, G. A.

doi: 10.1530/jrf.0.0370299pmid: 4596291

Summary.Sera from guinea-pigs immunized with their own spermatozoa or with purified preparations of three different guinea-pig sperm autoantigens (S, P and T) were tested for their spermatotoxic and cytotoxic (towards immature sperm cells) properties in the presence of complement, as well as for their spermagglutinating properties. Autoimmune and anti-T sera exhibited the three properties with a high degree of tridimensional correlation. Anti-S and anti-P sera did not exhibit any of the three properties. The three properties could be specifically absorbed by T but not by S or P autoantigens. While P/anti-P and T/anti-T are both complement-fixing systems, only T is present at the cell surface and only anti-T will fix on living sperm cells. The biological and immunopathological consequences of the preceding results are discussed in relation to the ability of each one of the three sperm autoantigens to induce an autoimmune aspermatogenic orchitis.

ETZEL, V.; SCHENCK, B.; NEUMANN, F.

doi: 10.1530/jrf.0.0370315pmid: 4856833

Summary.Female guinea-pigs were treated with 50 mg cyproterone acetate (CA)/kg body weight/day from the 30th to the 45th day of pregnancy. Fifteen of their male offspring were reared and their sexual behaviour was observed. Eleven of the test males showed no signs of male sexual behaviour when in contact with females in oestrus. All the masculine behaviour patterns were observable in only one test male. When in contact with normal male animals, the test males showed signs of feminine sexual behaviour, but spontaneous lordosis reactions were not observed.After castration and treatment with 50 μg testosterone propionate per day, the male offspring of sows which had received CA treatment showed reduced masculine sexual behaviour by comparison with control animals which had undergone the same treatment.After treatment with 3 μg oestradiol benzoate and 0·2 mg progesterone, significantly longer lordosis reactions were observed in the test males than in the control males which had received the same treatment, but the reactions were significantly shorter than in ovariectomized females treated with oestradiol benzoate and progesterone.

RAO, A. JAGANNADHA; MOUDGAL, N. R.; RAJ, H. G. MADHWA; LIPNER, H.; GREEP, R. O.

doi: 10.1530/jrf.0.0370323pmid: 4824697

Summary.The relative rôles of FSH and LH in ovulation induction in immature and adult cycling rats and hamsters have been evaluated. Both heterologous purified pituitary hormones and homologous crude pituitary extracts have been used as ovulatory stimuli in immature animals primed with PMSG. Well-characterized FSH and LH antisera have been used in the above model systems to achieve specific neutralization of FSH and LH. The present study revealed that LH is the physiological trigger needed for induction of ovulation in both rats and hamsters and FSH cannot, by itself, induce ovulation in the total absence of LH.

FECHHEIMER, N. S.; BEATTY, R. A.

doi: 10.1530/jrf.0.0370331pmid: 4824698

Summary.Chromosomal analyses were made of 463 rabbit blastocysts drawn from thirty-nine superovulated does of four strains. Semen containing 1·5% diploid spermatozoa was taken from one strain only. Artificial insemination was conducted with untreated semen or with centrifuged fractions containing either 0·4% or 2·9% diploid spermatozoa. The results indicate that diploid spermatozoa are not a major cause of triploidy among embryos.The sex ratio scored chromosomally among 434 diploid blastocysts was 48·62 (±2·40)% males. With data in the literature incorporated, the average sex ratio among 1077 blastocysts (consistent over three species of mammal) became 50·42 (±1·52)% males. These figures may be taken to estimate the primary sex ratio. Sex ratio among blastocysts is extremely stable over various biological and experimental conditions.Twenty-three (5%) of the 463 analysable blastocysts were heteroploid. They comprised eight triploids (5 XXX, 3 XXY), four trisomics, four diploid/trisomic mosaics, one diploid/monosomic mosaic, four diploid/ tetraploid mosaics, one diploid/triploid mosaic and one triploid/ hexaploid mosaic. `Clustering' of heteroploids occurred in particular dams. Superovulation had no demonstrable effect on the incidence of heteroploidy. There is some evidence of genetic (dam strain) effects on the incidence.