Summary. After a single dose of ethane dimethanesulphonate (EDS) (75 mg/kg) to rats the prolonged antispermatogenic action is due to a temporary elimination of the functional Leydig cell population. Replacement therapy with testosterone propionate (3 mg/day) maintains the spermatogenic epithelium but the EDS effect develops when hormone treatment is discontinued. In contrast, a short treatment with hCG (10–100 i.u./day) or LH (714 μg/day), starting before the EDS dose, permanently protects the spermatogenic epithelium. FSH treatment was completely ineffective. Although histological protection of spermatogenesis appeared complete with testosterone or hCG, effects on fertility remained but over different periods of time. Antispermatogenic and antifertility effects were produced in mice using much higher doses of EDS (5 × 250 mg/kg) but there was no protection from androgen or hCG. It is suggested that EDS binds to Leydig cells irreversibly, interfering with the action of gonadotrophin. At the dose level used the evidence suggests that the degree of reaction renders most of the Leydig cell population non-viable. A direct cytotoxic effect of the compound upon the spermatogenic epithelium might account for the inability of testosterone or hCG alone or in combination to maintain fertility at normal levels.
C. Marion Jackson and H. Jackson
C Jackson and RT Bernard
The effects of a reduction in ambient temperature (from 26 degrees C to 15 degrees C) and a 10% reduction in daily food consumption on reproductively active male and female four-striped field mice ( Rhabdomys pumilio) were investigated. In male R. pumilio, both reduced ambient temperature and a reduction in food quantity had an inhibitory effect on spermatogenesis and on size of the reproductive organs, and this was greatest when the two factors were combined and the effect of fat was removed. Female R. pumilio responded differently and reproduction was inhibited by a reduction in food quantity, irrespective of ambient temperature. The masses of the ovaries and uterus, the numbers of developing follicles and corpora lutea, and the development of the uterine wall were all reduced by food deprivation at 26 degrees C to levels similar to those that resulted from a reduction in ambient temperature to 15 degrees C with a reduction in food quantity. It is concluded that reproduction in R. pumilio from the Eastern Cape Province of South Africa is opportunistic, that reproduction will be inhibited by an energetic challenge and that there is sexual dimorphism in the response to ambient temperature and food supply.
MARGARET C. N. JACKSON
First I would like to thank the Trustees of the Oliver Bird Trust for the honou they have done me in asking me to give this lecture; and then I must admit my considerable misgivings in accepting; these have grown, not diminished, during the time that I have been thinking about and writing the paper. I have no doubt this is partly because my five predecessors have all been high-powered scientists with considerable reputations and academic records, whereas I come before you as a mere clinician—and not a very good one at that—with no claim to fame whatever except the rather dubious one of having been the medical officer to a Family Planning Clinic for more than 30 years and perhaps I could add (because I think this is one of the most useful things I have ever done) one of
H. JACKSON, C. MARION JACKSON and PAMELA JONES
For the most part, the antifertility actions of non-steroidal chemicals in male rats do not appear directly to involve the endocrine system (Jackson, 1970). In this species, administration of ethylenedimethanesulphonate (EDS) is accompanied by a temporary involution of both the ventral prostate and the seminal vesicles (Cooper & Jackson, 1970). This observation naturally led to an investigation of how far the antispermatogenic and antifertility actions of this compound involved the endocrine system, particularly the production and secretion of androgen. Treatment with EDS also inhibits the spermatogenic process in the mouse (Cooper & Jackson, 1970), in Japanese quail (Jones, Kominkova & Jackson, 1972) and in the parasitic worm, Schistosoma mansoni (Davies & Jackson, 1970).
After a single dose of the compound (75 mg/kg intraperitoneally), rats were sterile by Week 2 and remained thus for about 8 weeks
N. C. Jackson, H. Jackson, J. H. Shanks, J. S. Dixon and R. G. Lendon
Summary. Gonadotrophin binding to rat Leydig cells after a single administration of ethylene dimethanesulphonate (EDS) (75mg/kg i.p.) was followed by using intratesticular microdoses of 125I-labelled hCG, whilst corresponding morphological changes in the testicular interstitium were studied with light and electron microscopy. No discernible effect on 125I-labelled hCG binding compared with controls was observed until 24 h after treatment. Between 24 and 32 h a sharp decline in binding occurred which was correlated with extensive Leydig cell destruction. By 48 h the 125I-labelled hCG binding was negligible and no morphologically recognizable Leydig cells were found at this time. The specific binding remained low until 21 days after treatment and then a marked increase occurred to give nearly normal levels by 49 days. This was consistent with a generalized repopulation of the interstitium with Leydig cells, seemingly the result of differentiation of fibroblast-like precursor cells.
S. C. Langley-Evans, D. S. Gardner and A. A. Jackson
In human populations, patterns of disproportionate fetal growth are associated with cardiovascular disease in later life. Protein restriction of pregnant rats is known to impair fetal growth and is also associated with increased systolic blood pressure in later life. Growth of fetuses exposed to maternal low protein diets was found to be accelerated between day 14 and day 20 of gestation, but this growth appeared to falter in late gestation, resulting in low or normal birthweights. Placental growth was also accelerated by protein restriction. Day 20 fetuses from rats fed low protein diets were heavier but had proportionally smaller brains than did control fetuses. These animals were also longer in proportion to body mass. Between day 20 and full term (day 22), growth of the brain was spared at the expense of the trunk and at birth, pups exposed to low protein were short in relation to body mass. At weaning, rats exposed to low protein diets in utero had significantly higher systolic blood pressure relative to control animals. These data indicate that increased blood pressure in rats is linked to disproportionate patterns of growth in middle and late gestation.
P. ECKSTEIN, MARGARET C. N. JACKSON, N. MILLMAN and A. J. SOBRERO
In order to decide whether the rabbit method or the rhesus monkey test is better suited for routine vaginal tolerance tests of spermicidal preparations, combined trials employing both techniques were carried out in the two laboratories in which the tests had been developed.
A `double-blind' experimental design was used in which three unknown, coded compounds were tested jointly in both laboratories and evaluated independently and reciprocally after transatlantic exchange of the resulting histological material. Both test methods and the scoring systems employed in the assessment of findings are described and illustrated by representative photomicrographs.
There was good agreement between both methods for two of the three preparations tested. For the third preparation, the rabbit test results were more consistent with the available clinical data than those of the monkey test.
It was concluded that the rabbit technique is more sensitive than the monkey test. Since it has several obvious practical advantages over the latter, it is proposed that the rabbit vagina test should be generally adopted as the standard method for establishing the local tolerance of new spermicidal preparations for vaginal use.
R. J. Wordinger, A. E. Moss, T. Lockard, D. Gray, I-F. C. Chang and T. L. Jackson
Summary. Uterine samples were either rapidly frozen in liquid nitrogen or placed in Bouin's fixative. A commercial primary polyclonal antibody made in rabbits against human recombinant basic fibroblast growth factor (bFGF) was used. Western blot analysis indicated that the antibody was specific for bFGF and did not react with acidic FGF. The primary antibody was followed by either goat anti-rabbit immunoglobulin G (IgG) conjugated to the fluorescent phycobiliprotein tracer phycoerythrin or biotinylated goat anti-rabbit IgG and a biotin–avidin–peroxidase complex. Specificity controls using adjacent sections were carried out by (i) substituting normal rabbit sera for the primary antisera, (ii) omitting the primary antisera or (iii) extracting sections with NaCl (2 mol l−1) prior to the immunochemical procedures. No binding of the antibody was observed with any of the specificity control sections. The connective tissue stroma and the basal lamina associated with uterine glandular and surface epithelial layers were positive for bFGF. Localization was not observed within surface or glandular epithelial cells. The basal lamina and endothelial cells associated with blood vessels within the uterus and the smooth muscle cells of the myometrium were positive for bFGF. There were no differences in uterine localization patterns or intensity during the oestrous cycle or after ovariectomy and steroid hormone supplementation. These studies demonstrate the specific localization of bFGF within the mouse uterus.
Keywords: basic fibroblast growth factor; mouse
Linda Lefièvre, Kweku Bedu-Addo, Sarah J Conner, Gisela S M Machado-Oliveira, Yongjian Chen, Jackson C Kirkman-Brown, Masoud A Afnan, Stephen J Publicover, W Christopher L Ford and Christopher L R Barratt
Although sperm dysfunction is the single most common cause of infertility, we have poor methods of diagnosis and surprisingly no effective treatment (excluding assisted reproductive technology). In this review, we challenge the usefulness of a basic semen analysis and argue that a new paradigm is required immediately. We discuss the use of at-home screening to potentially improve the diagnosis of the male and to streamline the management of the sub-fertile couple. Additionally, we outline the recent progress in the field, for example, in proteomics, which will allow the development of new biomarkers of sperm function. This new knowledge will transform our understanding of the spermatozoon as a machine and is likely to lead to non-ART treatments for men with sperm dysfunction.