Manipulation of Ovarian Function Significantly Influenced Trabecular and Cortical Bone Volume,Architecture and Density in Mice at Death

Previously, transplantation of ovaries from young, cycling mice into old, postreproductive-age mice increased life span and decreased cardiomyopathy at death. We anticipated that the same factors that increased life span and decreased cardiomyopathy could also influence the progression of orthopedic disease. At 11 months of age, prepubertally ovariectomized and ovary-intact mice (including reproductively cycling and acyclic mice) received new 60-day-old ovaries. At death, epiphyseal bone in the proximal tibia and the distal femur and mid-shaft tibial and femoral diaphyseal bone was analyzed with micro-computed tomography. For qualitative analysis of osteophytosis, we also included mineralized connective tissue within the stifle joint. Prepubertal ovariectomy had the greatest influence on bone volume, ovarian transplantation had the greatest influence on bone architecture and both treatments influenced bone density. Ovarian transplantation increased cortical, but not trabecular bone density and tended to increase osteophytosis and heterotopic mineralization, except in acyclic recipients. These effects may have been dictated by the timing of the treatments, with ovariectomy appearing to influence early development and ovarian transplantation limited to influencing only the postreproductive period. However, major differences observed between cycling, acyclic and ovariectomized recipients of new ovaries may have been, in part due to differences in the levels of hormone receptors present and the responsiveness of specific bone processes to hormone signaling. Changes that resulted from these treatments may represent a compensatory response to normal age-associated, negative, orthopedic changes. Alternatively, differences between treatments may simply be the ''preservation'' of unblemished orthopedic conditions, prior to the influence of negative, age-associated effects. These findings may suggest that in women, tailoring hormone replacement therapy to the patient''s current reproductive status may improve therapy effectiveness and that beginning therapy earlier may help preserve trabecular bone mineral density that would otherwise be lost during perimenopause.     

Functionality of cryopreserved juvenile ovaries from mutant mice in different genetic background strains after allotransplantation

The rapid expansion of mutant mouse colonies for biomedical research has resulted in lack of space at laboratory animal facilities and increasing risks of losing precious lines. These challenges require cheap and effective methods in addition to freezing embryos and sperm to archive the expanding mutant mouse lines. Cryopreservation of mouse ovarian tissue has been reported, but the application in the diverse mutant lines and genetic backgrounds has not yet been studied. In this study, juvenile ovaries (10-day-old) collected from genetically modified mouse lines were cryopreserved using high concentrations of cryoprotectants (dimethyl sulfoxide (Me₂SO) and ethylene glycol (EG)) and instrumented ultra-rapid freezing. The validation of the frozen ovary batches was assessed by orthotopically transplanting a thawed ovary into a nearly completely ovariectomized mature female (congenic with the ovary donor). After 2 weeks of recovery, the ovary recipient was continuously paired with a male (congenic with the ovary donor) to evaluate the fertility of the recipient and delivered offspring were genotyped to evaluate the continued functionality of the grafted ovary. The recipient females delivered genetically modified offspring starting 6 weeks after ovary transplantation and lasting up to 6 months. The presented cryopreservation and transplantation protocols enabled retrieval of the genetic modification in 20 (from 22) genetically modified mutant mouse models on a C57BL/6 (17), FVB (2), or BALB/c (1) background. The thawed ovaries functioned after successful orthotopic allotransplantation to congenic wild-type recipients and produced mutant offspring, which allowed recreation of the desired genotype as a heterozygote on the proper genetic background. The results indicate that cryopreservation of mouse ovaries is a promising method to preserve genetic modification of the increasing number of mutant mouse models and can be used as a model for ovary cryopreservation using a variety of mouse mutants.     

Promoting effect of ovariectomy on hepatocellular tumorigenesis induced in mice by 3'-methyl-4-dimethylaminoazobenzene.

The treatment of female C57BL/6 x DS-F1 mice with 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) at 10, 12, 14, 16 and 18 days of age resulted in the development of hepatocellular adenomatous nodules after 10 months of age. Ovariectomy in these mice at 1 month of age hastened the development of adenomatous nodules, which then first appeared at 8 months of age. The incidence of adenomatous nodules in females ovariectomized at the age of 1 month was much higher than that in intact females of the same age. These results showed that the ovaries exerted a suppressive effect on the development of adenomatous nodules. To determine the time from which the ovaries exert this suppressive effect, females were ovariectomized at 4, 6, 8, and 10 months of age, and the incidences of adenomatous nodules were compared at 10 and 12 months of age. Delayed ovariectomy after 8 months of age did decrease the incidence of adenomatous nodules at 10 and 12 months of age, but ovariectomy after 4 and 6 months of age did not. When the incidence of adenomatous nodules in females ovariectomized at 10 months of age was examined over the subsequent 6 months, it became significantly higher after 14 months of age compared with that in intact females. The results show that the ovariectomy has the promoting effect on the development of adenomatous nodules in the liver induced by 3'-Me-DAB after 6 months of age.     

Preservation of femoral bone thickness in middle age predicts survival in genetically heterogeneous mice

To see whether age-related changes in bone could predict subsequent lifespan, we measured multiple aspects of femur size and shape at 4, 15, and 24 months of age in genetically heterogeneous mice. Mice whose cortical bone became thicker from 4 to 15 months, associated with preservation of the endosteal perimeter, survived longer than mice whose endosteal cavity expanded, at the expense of cortical bone, over this age range. Femur size at age 4 months was also associated with a difference in life expectancy: mice with larger bones (measured by length, cortical thickness, or periosteal perimeter) had shorter lifespans. Femur length, midlife change in cortical bone thickness, and midlife values of CD8 T memory cells each added significant power for longevity prediction. Mice in the upper half of the population for each of these three endpoints lived, on average, 103 days (12%) longer than mice with the opposite characteristics. Thus, measures of young adult bone dimensions, changes as a result of bone remodeling in middle age, and immunological maturation provide partially independent indices of aging processes that together help to determine lifespan in genetically heterogeneous mice.     

Cryogenic effect of antifreeze protein on transgenic mouse ovaries and the production of live offspring by orthotopic transplantation of cryopreserved mouse ovaries

The purpose of the present study was to evaluate the cryogenic effect of antifreeze protein (AFP) on transgenic mouse ovaries which is expressed AFP type III from Ocean pout and the production of live offspring by orthotopic transplantation of cryopreserved mouse ovaries. In this study, whole transgenic and nontransgenic mouse ovaries were vitrified with 20% DMSO and 20% EG in M2 medium supplemented with 0.5 M sucrose. All vitrified and toxicity control and fresh ovaries were transplanted orthotopically into ovariectomized recipients bilaterally. For fresh ovaries transplantation, 5 mice delivered litters of 18 and 19 live pups in first and second matings, respectively. For toxicity control of chemicals, 6 mice delivered litters of 22 and 23 live pups. For nontransgenic mouse ovaries (vitrified) transplantation, 7 mice delivered litters of 22 and 23 live pups. For transgenic mouse ovaries (vitrified) transplantation, 10 mice delivered litters of 35 and 37 live pups. Litter sizes from pups of freshly transplanted ovaries were not significantly different from AFP-transplanted transgenic ovaries but those from nontransgenic-transplanted ovaries were significantly different from the AFP-transplanted transgenic ovaries group (P < 0.05). In this study, for the first time, it was shown that the ovarian tissue of AFP transgenic mice was protected from cryopreservation by vitrification. These results demonstrate that a normal reproductive lifespan can be restored by orthotopic transplantation of AFP transgenic-vitrified ovary.     

Circannual and seasonal variations in plasma luteinizing hormone levels of ovariectomized ground squirrels (Spermophilus lateralis)

Plasma luteinizing hormone (LH) levels were determined at monthly intervals in intact and ovariectomized squirrels maintained in a constant 14L:10D photoperiod at a temperature of 23 +/- 2 degrees C. LH was undetectable (less than 0.9 ng/ml) in plasma of intact females at all times of year. Females ovariectomized (OVX) at 9.5 months of age in March showed substantial increases in plasma LH in May and June but LH was undetectable between July and November. Females ovariectomized at 13 months of age in July first manifested detectable LH levels the following January and February (6-7 months post-ovariectomy). Very few adult females trapped in May and ovariectomized in August had detectable LH levels within 2 months of ovariectomy; however, females ovariectomized the following February had detectable LH titers 1 month later. Long-term studies of individual OVX squirrels indicated peak LH levels between March and June, 1980, relatively low or undetectable titers between August and December and elevated LH levels between January and March, 1981. The results are suggestive of a circannual rhythm of LH secretion which appears restricted to one season of the year and occurs independently of steroid feedback from the ovaries; ovarian steroids only modulate the levels of plasma LH during the brief annual period of hypothalamo-hypophysial activity. We suggest that onset and termination of LH release are mediated by central nervous system circannual clocks.     

Prolongation and cessation of estrous cycles in aging C57BL/6J mice are differentially regulated events

The relative contributions of ovarian failure and hypothalamic-pituitary dysfunction to the prolongation and cessation of estrous cycles were assessed by measuring the ability of acutely ovariectomized (OVX) middle-aged (12 mo) mice to cycle after receiving grafts (under the renal capsule) of ovaries from young (2 mo) mice. The potentially disruptive effect of the acyclic state on the cycling response to grafted, young ovaries was avoided restricting grafting to middle-aged hosts that were still cycling. The effect of chronic exposure to ovarian secretions before the cessation of cyclicity on age-related hypothalamic-pituitary dysfunction was also assessed. The cycling ability of long-term OVX middle-aged mice (i.e., OVX at 3 mo) bearing grafts of young ovaries was compared to that of age-matched acutely OVX controls. Grafted young ovaries extended the cycling lifespan of acutely OVX middle-aged hosts by 60%. The length of this extended cycling lifespan, however, was only 80% of that achieved by young hosts bearing grafts of young ovaries. Young ovaries in middle-aged mice markedly lowered the incidence of long cycles (greater than 5 days), shifting the modal cycle length to 5 days. However, young ovaries in middle-aged mice failed to increase the incidence of 4-day cycles, the modal cycle of young controls. Middle-aged ovaries grafted into young hosts lengthened their cycles and shortened their cycling lifespan to middle-aged values. Long-term ovariectomy failed to increase the cycling lifespan of middle-aged hosts bearing grafts of young ovaries beyond that achieved in acutely OVX mice. Long-term ovariectomy did shorten the modal cycle length of middle-aged mice to 4 days, although the duration of 4-day cycling was only one-third (2 mo) that of young controls. These results indicate that the relative contributions of ovarian and neuroendocrine factors to three major events of reproductive aging vary with each event. Whereas the hypothalamic-pituitary unit appears to play an important role in the initial shift from 4- to 5-day cycles, the aging ovary plays the major role in the subsequent shift to longer cycles and in the ultimate cessation of cyclicity. Although chronic exposure to ovarian secretions during the period of cyclicity does not play a major role in the cessation of cyclicity, it appears to contribute to the hypothalamic-pituitary changes responsible for the initial shift from 4- to 5-day cycles.     

Transplantation of young ovaries restored cardioprotective influence in postreproductive-aged mice

The female cardioprotective advantage, present in mammals of a reproductively competent age, is lost during the transition to a postreproductive state. The role of reproductive hormones in this transition is most evident in women with premature ovarian failure, where reduced estrogen production has been associated with an increased incidence of early death from cardiovascular disease. Previously, we reported that postreproductive-aged mice that received young ovaries displayed an increased life span. Subsequent histopathological analysis suggested the presence of a cardioprotective effect associated with the restoration of ovarian influence. This restoration in postreproductive-aged mice produced a sharp decrease in evidence of significant cardiomyopathy at death, compared with sham-transplanted mice (36.0% vs. 73.3%, respectively). Within the intact transplant group, evidence of cardiomyopathy at death was decreased in mice that were reproductively cycling at the time of transplant, compared with acyclic mice (26.7% vs. 50.0%, respectively). This observation reflects the importance of timing in restoration of ovarian influence in this study. Transplantation of young ovaries to intact, postreproductive-aged female mice provided significant, long-term restoration of a cardioprotective benefit, similar to that previously present during a reproductively competent age. In these mice, restoration of ovarian influence through ovarian transplantation may, in effect, have postponed the advance of age-associated cardiomyopathy to a point where the disease did not reach a clinically relevant threshold during the lifetime of the recipients. These results offer support for previous clinical observations suggesting that hormone replacement therapy can produce divergent results if initiated during the perimenopausal period, compared with the postmenopausal ages.     

Age-related changes in ovarian responsiveness to gonadotropins in normal and neonatally estrogenized mice

Young ovariectomized mice were transplanted with ovaries obtained from either neonatally estrogenized or normal mice at different ages. Cyclic estrus ensued in 71% of the mice receiving ovarian grafts from 3-month-old normal donors. If donors were 12, 15 and 20 months old, cyclic estrus took place in 15, 10 and 0% of the recipients, respectively. By contrast, after transplantation of ovaries from neonatally estrogenized mice, and 3, 12 or 15 months, cyclic estrus occurred in about 42-48% of the recipients regardless of the age of donors. Three of 17 recipients receiving ovarian grafts from 20-month-old neonatally estrogenized donors still showed cyclic estrus. Therefore, in neonatally estrogenized mice, decline of ovarian responsiveness to circulating gonadotropins appears to be inhibited or delayed until at least 15 months of age.     

Fetal effects on sexual behavior and aggression in young and old female mice treated with estrogen and testosterone

During fetal life female mice (Mus musculus) that develop between two male fetuses (2M females) have higher blood concentrations of testosterone than do females that do not develop next to a male fetus (0M females). In the first experiment reported here, sexual receptivity and sexual attractiveness to males were examined in young (5 month old) and old (17 month old) ovariectomized, estrogen- and progesterone-treated 0M and 2M female mice that were placed in like-age pairs with a male. Most males inseminated the 0M female prior to inseminating the 2M female regardless of age. In addition, 0M females were more likely to exhibit lordosis when mounted than were 2M females. When the same young females were 9 months of age and the old females were 21 months of age, they were treated with testosterone and again placed together in pairs along with a sexually receptive female. Young 2M females exhibited more aggression toward the testosterone-treated female partner, and also exhibited more mounting of the receptive female, than did young 0M females. But, both old 0M and old 2M females were highly aggressive and exhibited mounting. An increase in sensitivity to the effects of testosterone on behavior thus occurs during aging in 0M females, which are relatively insensitive to testosterone in young adulthood. In contrast, when treated with estrogen and progesterone, 0M females were more attractive to males and were more sexually receptive than 2M females regardless of age.     

Maturation of mouse primordial follicles by combination of grafting and in vitro culture

Cryopreservation of ovarian cortical tissue and subsequent transplantation or in vitro culture of follicles are technologies under development with the aim to safeguard fertility in patients with gonadal failure. In the present study, we investigated whether primordial follicles could be triggered to full maturation by a combination of in vivo transplantation and in vitro culture in a mouse model. In a first step, newborn mouse ovaries containing only primordial follicles were allotransplanted under the renal capsule of ovariectomized recipient mice. The second step was to mechanically isolate growing preantral follicles from the graft and culture these in vitro to maturity. In our experiment, one newborn mouse ovary was transplanted under the renal capsule of each 8- to 12-wk-old F1 (C57Bl/6j x CBA/Ca) female ovariectomized recipient (n = 26). Two weeks after transplantation, all 26 grafts were recovered. Four grafts were processed for histology and showed that developmental stages of follicles in 14-day-old ovarian grafts were comparable to those in 14-day-old mouse ovaries. The 22 remaining grafts were used for mechanical isolation of preantral follicles. As a control group, preantral follicles isolated from ovaries of 14-day-old mice were used. The mean preantral follicle yield per ovary was 11 in the transplant group versus 33 in the control group. Follicles were cultured individually in 20-microliter droplets of alpha-MEM supplemented with 100 mIU rFSH and 5% fetal bovine serum for 12 days under an atmosphere of 5% CO(2) in air at 37 degrees C. By Day 12 of culture, 66.5% of follicles retained their oocytes in the grafting group versus 97.5% in the control group (P < 0.001). Final oocyte maturation was induced by addition of 2.5 IU/ml hCG. At 14-16 h post-HCG, the percentages of oocytes showing germinal vesicle breakdown and polar body extrusion were significantly higher in the control group (90.6% and 82.8%) compared to the grafting group (60% and 45%). The mean diameter of the mature oocytes of the grafting group (69.9 +/- 4.45 micrometer) was similar to that of oocytes from the control group (70.5 +/- 2.35 micrometer). Our results suggest that maturation of mouse primordial follicles is feasible by combination of in vivo transplantation and in vitro culture. This two-step strategy may be an attractive model for promoting the growth and maturation of primordial follicles from other species.     

The structure of the spiny mouse (Acomys cahirinus) ovary during development

The study presents the structure of the ovaries of the spiny mouse (Acomys cahirinus) during the first months of life. The ovaries in neonate females exhibit a large number of primordial and primary follicles, sometimes clustered in nests. The growing follicles were also observed within the ovary at that period. The first, early antral follicles appeared in the ovary during the second week of life. In the group of 60-day old females, the structure of the ovaries was characterized by a significant increase in the connective tissue elements. Moreover, ovarian follicles at various stages of development were observed, except for the antral ones with cumulus oophorus. The first mature follicles were identified in 3-month old females. In the ovarian follicles, apoptosis occurs at all stages of follicle development, especially in the early antral follicles. In the atretic follicles, apoptotic cells were identified in the layer of granulosa cells.     

Structural and functional changes in ovaries from adult mice treated with diethylstilboestrol in the neonatal period

Ovaries from 8-week-old female NMRI mice in different stages of the oestrous cycle, or from females neonatally treated with the synthetic oestrogen diethylstilboestrol (DES; 5-10(-6) micrograms daily for 5 days), were studied histologically and for the ability to synthesize steroids from [3H]pregnenolone in vitro. Daily doses of 10(-4) micrograms DES or higher resulted in absence of corpora lutea. In ovaries lacking corpora lutea, the interstitial tissue dominated and the cells in this compartment were large with a clear cytoplasm. The steroids synthesized in ovarian homogenates were separated with thin-layer chromatography. The homogeneity of the steroids was checked in recrystallization experiments. Daily doses of 5-10(-4) micrograms DES in the neonatal period resulted in pronounced deviations in the pattern of ovarian steroids synthesized as compared with control ovaries. In DES-exposed ovaries, the synthesis of androstenedione and, above all, progesterone was high while the synthesis of 17 alpha-hydroxyprogesterone and testosterone was reduced compared with controls. These results could argue for a difference in activities of 17 alpha-hydroxylase and 17 beta-ol-dehydrogenase in ovaries from DES-treated females compared with controls. After transplantation of DES-exposed ovaries to ovariectomized control females, the steroid pattern changed to that typical for control ovaries. Control ovaries transplanted to DES-treated females had a steroid pattern similar to that of DES-exposed ovaries.     

Fertilized eggs obtained from transplantation of frozen ovaries and parthenogenesis in combination with artificial insemination of frozen semen of the silkworm,Bombyx mori

A reliable method is reported for the long-term preservation of ovaries and spermatozoa of the silkworm (Bombyx mori). Three studies are presented. In the first, ovaries were removed from larvae at either 3rd, 4th, or 5th instar, cryopreserved, and stored in liquid nitrogen. Thawed ovaries were transplanted to surgically castrated female larvae at the same or a different developmental stage. The highest percentage of recipient females producing eggs resulted into either 3rd or 4th instar larvae (respectively, 22.1 and 8.7%). Similarly, the highest levels of other measurements of successful cryopreservation and transplanted ovary, and number of eggs laid, occurred with the same combination of donor and recipient developmental stages. Other combinations of ovary/recipient developmental stages yielded lower results. In the second experiment, semen was collected from male moths, cryopreserved, and then thawed semen was diluted with trypsin solution and artificially inseminated into females obtained from the best conditions of first experiment. A small percentage of inseminated moths laid eggs (8-10.3%) compared to that of controls (100%). In addition, the fertility of eggs from experimental moths was lower than that of control females (respectively, 40.3-88% and 97.5%). In the third experiment, eggs were surgically removed from ovarian tubules of moth following transplantation of thawed ovaries and subjected to parthenogenetic activation and artificial hatching. As expected, all resulting moths were female and, following natural mating or artificial insemination with thawed semen, yielded normal offspring at high rates.     

Flow-mediated vasodilation is impaired in adult rat offspring exposed to prenatal hypoxia

There is now a demonstrated association between low birth weight and increased mortality later in life. Changes in fetal development may program the cardiovascular system and lead to an increased risk of cardiovascular diseases later in life. In addition, aging is a risk factor for vascular endothelial-dependent dysfunction. However, the impact of being born intrauterine growth restricted (IUGR) on the normal aging mechanisms of vascular dysfunction is not clear. We hypothesized that IUGR would cause changes in vascular function that would affect the mechanisms of flow-induced vasodilation later in life in an age- or sex-dependent manner. To create an IUGR model, pregnant Sprague-Dawley rats were placed in a hypoxic (11.5% O?) or control (room air, 21% O?) environment from days 15 to 21 of pregnancy. Both male and female offspring were investigated at 4 or 12 mo of age. Vascular function was assessed in small mesenteric arteries using flow-induced vasodilation, a physiological stimuli of vasodilation, in a pressure myograph. Flow-induced vasodilation was unaffected at a young age, but was significantly reduced in aging IUGR compared with aging controls (P < 0.05). Underlying vasodilator mechanisms were altered such that nitric oxide-mediated vasodilation was abolished in both young adult and aging IUGR males and females and in aging control females (P > 0.05). Endothelium-derived hyperpolarizing factor-mediated vasodilation was maintained in all groups (P < 0.01). A change in the mechanisms of vasodilation occurring at an earlier age in IUGR offspring may predispose them to develop cardiovascular diseases as an aging adult.     

Delayed anovulatory syndrome induced by estradiol in female C57BL/6J mice: age-like neuroendocrine, but not ovarian, impairments

These studies describe induction of a delayed anovulatory syndrome (DAS) by estradiol (E2) in female C57BL/6J mice. Six days after birth, female mice were injected s.c. with 0.1 micrograms estradiol benzoate or oil. Over 90% of the oil-injected controls exhibited estrous cycles from 2 to 9 mo of age. In contrast, 60% of the E2-injected mice exhibited estrous cycles at 2 mo of age but were acyclic by 9 mo; these mice were considered to have exhibited a DAS, and had longer cycles than controls. At 12 mo, ovarian impairments were assessed by examining 1) ovulation after s.c. injection of 5 IU human chorionic gonadotropin (hCG), and 2) estrous cycles after grafting into young (3-mo-old) hosts. Simultaneously, neuroendocrine impairments were assessed by examining 1) the surge of luteinizing hormone (LH) induced by E2 implants after ovariectomy, and 2) estrous cycles after receiving ovarian grafts from 3-mo-old mice. Ovaries from DAS and control mice ovulated equally in response to hCG. Ovaries from DAS mice grafted into young ovariectomized hosts supported 30% more cycles, of shorter period, compared with ovaries from control donors. However, the E2-induced LH surge was 50% smaller in DAS mice than in controls. Ovariectomized DAS hosts with ovarian grafts from young mice supported 70% fewer estrous cycles, of longer period, compared with ovariectomized control hosts with young grafts. We conclude that the E2-induced DAS in female mice is not due to ovarian impairments, but seems to result from neuroendocrine impairments.     

Study of persistence of maternal antibodies to varicella-zoster virus by indirect haemagglutination, with result control by radioimmunoassay

The persistence of maternal antibody against varicella-zoster virus was studied by the method of indirect haemagglutination (IH) and a control of the results was performed by radioimmunoassay (RIA). The findings were analysed with reference to the constant half-life of passively acquired IgG and the titre range and frequency of antibodies in 220 persons of fertile age representative of the normal population. Statistical analysis of expected and the experimentally obtained data was performed. Among the normal population, the expectancy is a gradual decrease in maternal IH antibody titres to negativity during the first 10 months of life and 100% sero-negativity by the 11th and 12th month. The experimental data showed a decrease in IH seropositivity from the initial 100% in 1-month infants to 27% in 6-month and 7% in 12-month infants. Nine out of twelve of the experimentally found positive titres in infants during the second half of their first year of life deviated from the normal population sample. The results obtained by both of the methods used were in good agreement.     

Demography,female life history,and reproductive profiles among the chimpanzees of Mahale

Demography provides critical data to increase our understanding of the evolution, ecology, and conservation of primate populations. The chimpanzees of the Mahale Mountains National Park, Tanzania, have been studied for more than 34 yr on the basis of individual identification and standardized attendance records. From this long-term study, we derived the following demographic data: The major cause of death was disease (48%), followed by senescence (24%) and within-species aggression (16%). Fifty percent of Mahale chimpanzees died before weaning. The median ages of female life history variables were: first maximal swelling, 10.0 yr (n = 5); emigration, 11.0 yr (n = 11); and first birth, 13.1 yr (n = 5). The median period of adolescent infertility was 2.8 yr (n = 4) when calculated from the age at immigration to that at first birth. Female fecundity was highest between 20 and 35 yr of age, with an annual birth rate of 0.2. Twenty-six females that were observed from a young age (10-13 yr) to death at various ages (15-40 yr) gave birth to an average of 3.9 and weaned an average of 1.4 offspring. Twenty-five females that were observed from middle age (18-33 yr) to death in older age (31-48) gave birth to an average of 2.7 and weaned an average of 2.0 offspring. The post-reproductive lifespan for female chimpanzees was defined as the number of years that passed from the year when the last offspring was born to the year when the female died, minus 5. Twenty-five percent of old females had a post-reproductive lifespan. The interbirth interval after the birth of a son (x = 72 mo) tended to be longer than that after the birth of a daughter (x = 66 mo). The extent of female transfer, which is a rule in chimpanzees, is influenced by the size and composition of the unit group and size of the overall local community.     

Adrenal and ovarian sources of progesterone secretion in young female fallow deer, Dama dama

Six young female fallow deer, including 3 that were ovariectomized at 9 months of age, were blood sampled at frequent intervals after i.v. injections of (1) ACTH analogue (tetracosactrin), (2) GnRH analogue (buserelin) and (3) saline solution on separate occasions at 11, 13, 15 and 18 months of age. Relative to prechallenge plasma values, ACTH administration resulted in a 4-10-fold increase in mean plasma progesterone concentrations, but only a 10-45% increase in mean plasma cortisol concentrations, within 40 min for entire and ovariectomized does during the prepubertal periods (11, 13 and 15 months) and for ovariectomized does during the post-pubertal period (18 months). Post-pubertal entire does exhibited high mean basal plasma progesterone concentrations (3-4 ng/ml) indicating a luteal source of secretion, with the ACTH-induced progesterone response being additive to the luteal progesterone but of similar magnitude to responses in the ovariectomized does. There was no significant ACTH challenge effect on mean plasma LH concentrations for entire or ovariectomized does at all ages. GnRH administration had no significant effects on mean plasma concentrations of progesterone and cortisol of entire and ovariectomized does, although there was a small increase in mean plasma progesterone values in post-pubertal does that may have reflected a luteal response to GnRH (via LH). GnRH challenge resulted in marked increases in mean plasma LH concentrations but the response patterns were different for the 2 types of does, being more rapid and of higher magnitude for ovariectomized does.(ABSTRACT TRUNCATED AT 250 WORDS)     

The life expectancy of phlebotomine sandflies: first field estimates from southern France

Abstract. 1. A field study of Phlebotomus ariasi Tonnoir, the vector of Leishmania infantum Nicolle in southern France, addressed the following questions: Is it possible to estimate reliably the life expectancy of this sandfly; can spatial or temporal variation in the life expectancy be detected, and is such variation significant for disease transmission? 2. Life expectancy was estimated by examining follicular relics in the ovaries of more than ten thousand females caught in light traps at seven sites in the Cévennes and the Garrigues, throughout their active period in 1985 and 1986. Whilst the distinction between nulliparous and parous flies was easily made, assessments of the number of times a parous fly had laid eggs were unreliable. Best estimates of life expectancy were therefore calculated from the parous rate. 3. Large samples collected from one site in the Cevennes in both years gave very similar estimates of life expectancy. 4. There was also no significant difference between estimates obtained from the Cévennes and the Garrigues, despite their distinct vegetation and climates. Therefore, large regional differences in sandfly population size and the prevalence of canine leishmaniasis cannot be explained by a difference in adult survival rate. 5. With no systematic annual or regional variation, a useful mean life expectancy can be calculated from the data collected at all sites in both years. It is 1.54 (SE 0.04) ovarian cycles. However, this estimate is sensitive to the assumption that survival rate is a discrete rather than a continuous variable. 6. Local variation in the parous rate may be associated with the proximity of traps to P.ariasi emergence sites.