Reproduction

EDDY, C. A.; BLACK, D. L.

doi: 10.1530/jrf.0.0330001pmid: 4699444

Summary.Chemical sympathectomy followed transluminal perfusion of the rabbit oviduct with 6-hydroxydopamine (6-OHDA). Histofluorescence studies 1 week after perfusion revealed an absence of formaldehyde-norepinephrine(NE)-induced fluorescence in treated oviducts while contralateral control oviducts which were not perfused exhibited normal fluorescence. Endogenous NE concentrations of treated and control oviducts and their associated uterine horns were measured biochemically 1 week after perfusion. A dose-dependent decrease in NE was demonstrated in 6-OHDA-perfused oviducts. By contrast, contralateral control oviducts and both uterine horns exhibited no significant decrease in endogenous NE until doses of 6-OHDA in excess of those required for functional denervation were perfused through treated oviducts.

FRASER, I. S.; BAIRD, D. T.; COCKBURN, F.

doi: 10.1530/jrf.0.0330011pmid: 4699436

Summary.Measurements of Po2, Pco2 and pH have been carried out in human ovarian venous, peripheral venous and arterial blood, and in ovarian follicular fluid. The Po2 in ovarian venous blood is higher than in peripheral venous blood. Mean oxygen consumption by the human ovary has been calculated to be 1·4 ml oxygen/100 g ovarian tissue/min. Taken in conjunction with a mean ovarian blood flow of 20·3 ml/min, these findings are compatible with the presence of arterio-venous shunts within the human ovary. Oxygen tension in follicular fluid may be substantially lower than oxygen tension in peripheral and ovarian venous blood.

BEDFORD, J. M.; BENT, M. J.; CALVIN, H.

doi: 10.1530/jrf.0.0330019pmid: 4573026

Summary.Decondensation of the nuclear chromatin of mammalian spermatozoa can be induced by treatment with sodium dodecyl sulphate (SDS) containing dithiothreitol (DTT)—a reagent which specifically cleaves -S-S- crosslinks. The nuclei of mature rabbit and monkey spermatozoa respond to SDS/DTT treatment in a uniform manner, each expanding to a similar degree, whereas those of the treated human ejaculate display a consistent heterogeneity between individual spermatozoa in their degree of decondensation which is unrelated to head shape.A variable proportion of the sperm nuclei from human ejaculates will swell in SDS alone and correlated ultrastructural studies indicate that these probably possess incompletely condensed chromatin of granular appearance. The heterogeneity of sperm nuclei in the human ejaculate revealed by combined treatment with SDS/DTT, on the other hand, is probably not visible at the ultrastructural level before such treatment. The decondensation induced by SDS/DTT allows detection of nuclear vacuoles which are not evident with the light microscope in intact spermatozoa. Such vacuoles were present in >90% of the spermatozoa of one individual whose ejaculate was otherwise normal.The finding that human sperm nuclei of normal shape may vary considerably with respect to the character of their chromatin raises several questions; these include the aetiology and molecular basis of such heterogeneity and the possible bearing these differences might have on the early development of the human embryo.The present technique of controlled nuclear decondensation provides a simple method by which the structural quality of sperm nuclei can be assessed.

LARSON, L. L.; SPILMAN, C. H.; DUNN, H. O.; FOOTE, R. H.

doi: 10.1530/jrf.0.0330031pmid: 4699445

Summary.The reproductive efficiency of twenty-eight aged does, 49 to 72 months old, was compared with that of eighteen young does, 6 to 13 months old. Fertilization rate and development in vitro of fertilized ova from rabbits induced to superovulate were not influenced by the doe's age. Ovulation rates following natural mating were only slightly reduced with age. However, the number of embryos per doe was much greater in young than in old does at 12 and 24 days post coitum. All young does had viable embryos, whereas the percentages of aged does with detectable implantation sites and viable embryos were 80 and 40, respectively, at 12 days post coitum, and 77 and 44 at 24 days post coitum.Aged female rabbits were given supplemental exogenous progesterone and/or oestradiol benzoate in an effort to increase reproductive efficiency. Progesterone treatment had no effect on the total number of young kindled but did prolong the gestation period, increase the birth weight and result in fewer live young kindled/doe. When administered on Days 3 to 29 of pregnancy, 4 μg/day of oestradiol alone or in combination with 2 and 4 mg progesterone completely blocked pregnancy in all does. Starting on Day 5 of pregnancy, oestradiol levels of 1 μg/day, with or without progesterone, had no effect.Chromosomal analysis of fourteen embryos revealed eleven normal females (44,XX), one normal male (44,XY), one abnormal embryo (45,XX) with an extra acrocentric chromosome and one embryo with a modal number of forty-two chromosomes in 35% of the metaphases. Since most of the embryonic wastage in aged rabbits occurred during the first 12 days post coitum, chromosome studies of embryos younger than 12 days post coitum are indicated.Most of the embryonic wastage could not be attributed to ovulation rate, fertilization rate, ovum potential, CL function, circulating levels of progesterone and oestrogen, or to chromosomal anomalies of the fetuses. It was concluded that uterine factors apparently limit reproductive performance in aged rabbits.

LAVON, U.; BRIGGS, P. A.; BOURSNELL, J. C.

doi: 10.1530/jrf.0.0330039pmid: 4699446

Summary.The protein patterns of boar seminal plasma, vesicular secretion and epididymal plasma and of their fractions obtained by gel filtration and dialysis were further studied by gel disc electrophoresis and isoelectric focusing on polyacrylamide.The majority of the seminal plasma proteins originate in the seminal vesicles and the quantitative contribution of the epididymides to the protein pattern is small. Proteins A, B and H were found to be mixtures of large numbers of proteins which were identified and characterized.

HOLT, W. V.; TAM, W. H.

doi: 10.1530/jrf.0.0330053pmid: 4699447

Summary.Using histochemical and in-vitro biochemical methods, the following steroid enzymes were found in the chin gland of the male cuis: 17 β-hydroxysteroid dehydrogenase, 5-ene-3β-hydroxysteroid dehydrogenase and 4-ene-5α-reductase. The chin gland did not metabolize [4-14C]progesterone but it did metabolize a small quantity of [7α-3H] pregnenolone to progesterone, and readily converted [4-14C]testosterone into androstenedione and 5α-androstane-3, 17-dione. These are catabolic products of testosterone. These findings, together with the possible rôle of the chin gland in sexual behaviour, may show that sebum has a communicative rôle in Galea musteloides and other mammals.

WEIR, BARBARA J.

doi: 10.1530/jrf.0.0330061pmid: 4735498

Summary.Further investigations were made in the chinchilla, Chinchilla laniger, on the induction of ovulation and oestrus. Chinchilla treated with exogenous gonadotrophins (PMSG and HCG) in various regimens came into oestrus (73%) and a mean number of 2·6 ova were ovulated per animal. Mating occurred in 18% and conception in 12% of the treated chinchilla. This response was considered promising for encouraging chinchilla to breed at all times of the year.

FOX, C. A.; MELDRUM, S. J.; WATSON, B. W.

doi: 10.1530/jrf.0.0330069pmid: 4699448

Summary.The use of the pH-pill has allowed continuous monitoring of vaginal pH during human coitus. In the case of a couple of normal fertility, there was an immediate buffering by seminal plasma so that the vaginal pH changed in 8 sec from pH 4·3 to pH 7·2. In the case of a couple of low (male) fertility, the immediate effect of the arrival of semen in the vagina was a change from pH 3·5 to pH 5·5. A similarly small change in pH occurred when the seminal volume of a fertile male subject had been depleted, by repeated ejaculation, to 1 ·5 ml. At this pH (5·5), spermatozoa are generally immobilized.It has been possible to alter normal fertility, as judged by postcoital tests for sperm motility, by the introduction of a pH 3·6 buffer solution into the vagina before coitus. In this latter experiment, the vaginal pH immediately after ejaculation was 5·0 and, after 2 hr, had reached pH 5·4.These results in vivo suggest that the vagina is not the hostile environment hitherto imagined, since the normal ejaculate readily overcomes the vaginal acidity by its powerful buffering action. Low seminal volume, with or without a concomitantly low sperm count, and artificial changes in vaginal environment by buffer solutions may affect fertility.

DEWAR, A. D.

doi: 10.1530/jrf.0.0330077pmid: 4699449

Summary.No significant effects on the duration of subsequent oestrous cycles, the duration of pseudopregnancy or on the other characteristics of pseudopregnancy were observed after hysterectomy in albino mice. In pregnancy, except for a slight transient effect on Day 10, the residual duration of luteal activity (as measured by the duration of the extrauterine weight loss and the interval to oestrus) was independent of the presence or absence of the uterus and pregnancy was maintained by a single contralateral ovary associated with an isolated non-pregnant horn.Loss of the placentae by hysterectomy or uterine evacuation on the 8th day of pregnancy had no influence on the duration of CL activity when compared with that of pseudopregnant animals. Thereafter, the duration of residual luteal activity declined to a near constant level from the 14th day onwards and this decline was accompanied by a reduction in the variability of the life of the CL normally seen in pseudopregnancy. Placental removal after the 14th day was followed by almost immediate cessation of luteal function which at no time (with the possible exception of the 18th day) continued for the remainder of the gestation period.

IMAI, KIYOSHI

doi: 10.1530/jrf.0.0330091pmid: 4699450

Summary.Fowl and mammalian pituitary preparations were injected intraperitoneally into hens (`ovulation-suppressed' following pretreatment with daily subcutaneous injections of PMSG) to determine their ovulation-inducing activities. Acetone-dried fowl (Gallus domesticus) and bovine anterior pituitaries (CAP and BAP), partially purified DEAEand CM-fractions prepared from CAP and CAP homogenate, and ovine NIH-FSH and -LH were used as the test preparations.Acetone-dried CAP induced multiple ovulations from three to five follicles in the ovulation-suppressed hens pretreated with PMSG, whereas no ovulation occurred after the injection of BAP. The DEAEfraction exhibited about the same activity as the CAP homogenate in the induction of multiple ovulations from three to six follicles, but the activity of the CM-fraction was considerably lower than that of the CAP homogenate and DEAE-fraction. Ovine FSH did not induce ovulation, whilst a single injection of ovine LH resulted in ovulations from one to three follicles. The number of ovulating follicles induced by the preparations originating from CAP was significantly more than that induced by ovine LH.