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R. G. Gosden, N. Brown, and Kay Grant

Summary. In a histological survey of 19 mammalian species, Call–Exner bodies of conventional size and appearance were found in only 5, namely, human, rhesus monkey, rabbit, guinea-pig and sheep. Rabbit ovaries were used for characterizing these bodies using quantitative histochemistry, lectin binding and electron microscopy. Call–Exner bodies were topographically distinct lacunae of the extracellular space probably containing hyaluronic acid with proteoglycan complexes. The staining characteristics of the antrum and Call–Exner bodies were generally similar. However, in contrast to the antrum, the smaller lacunae contained suspended filaments with a distinctive peripheral membrane upon which a rosette of granulosa cells was resting. The membrane and narrow intercellular clefts probably prevent much exchange of large glycosaminoglycan complexes with the antrum. The origin and significance of Call–Exner bodies require further study, but it is clear that they are associated with secretion rather than with necrosis as sometimes suggested.

Keywords: Call–Exner bodies; glycosaminoglycans; Graafian follicle; granulosa cell; lectin; rabbit

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D. Frances Edwards and R. Kay

Summary. The body weight of rats at spontaneous vaginal opening (Wvo) was related to the weight at weaning (Ww) and the time elapsed between the two events (t vo) by the following equation:

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where a j is the litter effect present when both the male and female young are reared together. When only female young are raised, a j may be replaced by a, so that in this instance there is no litter effect.

Further model differences were noted for young raised under different conditions.

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G. A. Lincoln and R. N. B. Kay

Summary. At 2–4 monthly intervals during the year blood samples were collected every 15 min for 6 h from 2 intact and 3 castrated red deer stags to study the relationship between season and the secretion of LH and testosterone. In the intact stags plasma LH and testosterone concentrations changed during the year; the LH levels were maximal in August during the phase of testicular redevelopment, while the testosterone levels were maximal from September to November coinciding with the time of peak testicular activity and the mating season. The castrated stags had higher plasma levels of LH than the intact stags at all times of the year, and there was no clear seasonal cycle in LH levels in these animals.

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J. M. Suttie, G. A. Lincoln, and R. N. B. Kay

Summary. Observations of body weight, testis size, antler status, plasma testosterone and prolactin were made on 12 red deer stags during their first 2 years of life. Six of the stags were fed to appetite throughout the study (Group A) and 6 were fed a 70% restricted diet during each winter (Group B). In addition 6 of the stags, 3 from each group, were studied in more detail; LH and testosterone were measured either after a single injection of LH-RH or in samples taken at frequent intervals over a period of 8 or 24 h. During the study the stags became sexually mature, developed first their pedicles and then antlers and showed at least one complete cycle of casting and regrowth of the antlers. The stags in Group A developed their testes and pedicles about 2 months earlier than did those in Group B. Pedicle initiation was associated with increasing plasma testosterone levels in response to changes in LH secretion, and antler development occurred when testosterone levels were low or decreasing. Cleaning of the velvet was associated with high levels of plasma testosterone. Antler casting occurred when plasma testosterone concentrations were low or undetectable and prolactin levels were high or increasing. The relationship between LH and testosterone varied during the study; in spring when the testes and antlers were growing, relatively high levels of LH were associated with only small peaks of testosterone, yet in summer, when antler growth was complete and the antlers were clean of velvet, low LH concentrations were associated with large peaks of testosterone.

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R. N. Murdoch, D. J. Kay, and M. Cross

Summary. The biochemical assay of alkaline phosphatase in the uterus of mice revealed a 13-fold increase in the activity of the enzyme during the peri-implantation period with a relatively short-lived maximum being reached on Day 7 of pregnancy. A similar increase in the activity of the enzyme occurred between Days 5 and 7 of pseudopregnancy in uterine horns of mice receiving a deciduoma-inducing stimulus on Day 4. The presence of factors in uterine homogenates which could possibly modify the activity of the enzyme could not be detected. Low and unaltered levels of alkaline phosphatase activity were found in the blood serum of mice between Days 1 and 10 of pregnancy, suggesting that no appreciable entry of the uterine enzyme into the circulation occurs in this species. Alkaline phosphatase activity in the uterine homogenates was associated with particulate fractions sedimented during centrifugation at 500, 10 000 and 105 000 g, and only about 29% of the activity was associated with the cytosol fraction. The subcellular distribution of the enzyme activity was the same in decidualized and non-decidualized horns. The association of the enzyme with the particulate material in uterine cells was considered to involve lipoprotein membranes because treatment of homogenates with 0·2% (v/v) Triton X-100 solubilized the enzyme without affecting its catalytic activity.

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The gross anatomy of the mammary gland of the red deer is described. A total of 102 milk samples was obtained from six deer (four during a complete lactation). These contained an average of 21·1 % total solids (8·5% fat) in early lactation, rising to 27·1% (13·1% fat) in late lactation.

Milk yields were measured by the calf-weighing technique. In well-fed hinds, peak yields of 1400 to 2000 g/day were reached early in lactation. One hind on a restricted food intake gave a maximum of 970 g/day. Lactation continued for 190 to over 280 days. Total yields for the first 150 days were estimated to be 140 to 180 kg in well-fed hinds and 65 kg in the underfed hind.

The feed intakes of the hinds rose during late pregnancy, and in early lactation rose again markedly, to a level about 2·4 to 2·6 times the maintenance requirement of non-breeding animals.

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Cleida A Oliveira, Germán A B Mahecha, Kay Carnes, Gail S Prins, Philippa T K Saunders, Luiz R França, and Rex A Hess

Estrogen receptors, in addition to the androgen receptor (AR), are expressed at high levels in efferent ductules of the male reproductive tract and it is now well recognized that estrogen receptor (ER) α is required for the maintenance of normal structure and function of the ductules. However, little is known regarding the hormonal regulation of the receptors themselves in the male. In the present study, efferent ductule ligation and castration, followed by replacement with testosterone, dihydro-testosterone (DHT) or estradiol was used to investigate the relative importance of circulating and luminal sources of steroid for the modulation of ERα, ERβ and AR in rat efferent ductules. Uni- or bilateral castration and ligation did not affect the expression of ERα and ERβ, but bilateral castration caused down-regulation of AR. Replacement with DHT and testosterone alone or in combination with estradiol caused the recovery of AR expression to control levels. A slight recovery of AR was also observed after estrogen replacement. ERα expression was decreased to nearly undetectable levels after estrogen replacement. On the other hand, ERβ did not show evident effects following any of the treatments, suggesting a constitutive expression of this receptor. This differential modulation of the steroid hormone receptors highlights the importance of maintaining a physiological androgen-estrogen balance to regulate the structure and function of efferent ductules in the male.

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Matthew T Rätsep, Allison M Felker, Vanessa R Kay, Leandra Tolusso, Alexander P Hofmann, and B Anne Croy

Mammalian pregnancy involves tremendous de novo maternal vascular construction to adequately support conceptus development. In early mouse decidua basalis (DB), maternal uterine natural killer (uNK) cells oversee this process directing various aspects during the formation of supportive vascular networks. The uNK cells recruited to early implantation site DB secrete numerous factors that act in the construction of early decidual vessels (neoangiogenesis) as well as in the alteration of the structural components of newly developing and existing vessels (pruning and remodeling). Although decidual and placental development sufficient to support live births occur in the absence of normally functioning uNK cells, development and structure of implantation site are optimized through the presence of normally activated uNK cells. Human NK cells are also recruited to early decidua. Gestational complications including recurrent spontaneous abortion, fetal growth restriction, preeclampsia, and preterm labor are linked with the absence of human NK cell activation via paternally inherited conceptus transplantation antigens. This review summarizes the roles that mouse uNK cells normally play in decidual neoangiogenesis and spiral artery remodeling in mouse pregnancy and briefly discusses changes in early developmental angiogenesis due to placental growth factor deficiency.