Work-family conflict, gender, and health-related outcomes: a study of employed parents in two community samples

Female sifaka mate selectively with one or more resident and/or non-resident males during the breeding season. Various adaptive explanations have been advanced to explain why female primates mate with multiple males including that 1) females seek to confuse paternity and thereby forestall male infanticide and/or ensure male infant care or 2) females seek to ensure fertilization. Assessing the power of fertilization insurance to explain mating patterns in females requires information on the temporal relationship between mating and ovarian hormones. The hormonal correlates of reproduction and mating in free-ranging Propithecus verreauxi were investigated using excreted steroids as indices of reproductive state. Solid-phase extraction and radioimmunoassay techniques were used to measure unconjugated estradiol (E(2)) and progesterone (P(4)) in 485 desiccated fecal samples collected from five female sifaka before and during the breeding season at Beza Mahafaly, Madagascar. Results suggest that behavioral estrus was characterized by 10 to 15-day elevations in E(2); hormonal activity was observed to be similar to pseudo-estrus reported for other lemur species; apparent conception was associated with sustained P4 elevations beginning 1 to 3 days post-estrus with gestational phase elevations of E2 beginning 42 to 45 days post-conception; and mating with multiple partners appeared not to be a prerequisite to fertilization, as conception resulted from both monoandrous and polyandrous matings. These preliminary data suggest that fertilization insurance is not adequate to explain polyandrous mating in sifaka at Beza Mahafaly.     

Behavioural correlates of testosterone and seasonal changes of steroids in red-winged blackbirds

I studied the relationship between behaviour and plasma testosterone level (T) and the seasonal changes in T and plasma corticosterone levels (B) in male red-winged blackbirds, Agelaius phoeniceus. I measured T and B using radioimmunoassay, and on the day after taking blood, I observed each male's behaviour for 60 min. The time that males spent conspicuously perched and the number of songs were positively correlated with T, but the proportion of time spent conspicuously perched and the frequency of song were not correlated with T. The frequency of aggressive encounters, sexual chases, epaulet exposure when singing and flights within the territory were positively correlated with T, suggesting a direct role for circulating testosterone influencing male aggressive behaviour. Both T and B increased early in the breeding season, peaked when the first females were receptive, and decreased through the remainder of the breeding season. Late in the season, the presence of a receptive female caused males to have increased T. The peak in T when the first females were receptive, the positive correlation between aggression and T, and the response to a receptive female with increased T support predictions of the challenge hypothesis. T was positively correlated with B, suggesting a cost to the males of maintaining high T. When a receptive female was present on the male's territory, T was negatively correlated with date. Male red-winged blackbirds in Indiana may respond less to receptive females late in the season when benefits associated with protecting paternity and gaining extra-pair fertilizations decrease.Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.     

A case of recessive X-linked ichthyosis: scale-specific abnormalities of lipid composition may explain the pathogenesis of the skin manifestation

Even though fecal incontinence is a leading cause of nursing home placement, risk factors contributing to its development have not been established. Identification of such factors may lead to prevention of incontinence and reduce the need for nursing home placement. A total of 388 residents of five nursing homes were included. Data regarding mental status, bowel habits, obstetrics history, and the presence, frequency, and severity of fecal incontinence were collected for each participant. Of the 388 nursing home residents, 46% were incontinent of feces. Incontinence was 1.5 times more common in males and in those younger than 65 years of age. In both univariate and multivariate analyses, diarrhea, dementia, restricted mobility, and male gender were independently associated with incontinence. In contrast to previous studies, constipation was not associated with fecal incontinence. If elimination of these risk factors leads to prevention of incontinence in even a few people, some elderly patients may not require institutionalization, which will result in improvement in their quality of life, not to mention a reduction in public health expenditures.     

Hormonal and behavioural correlates of male dominance and reproductive status in captive colonies of the naked mole-rat, Heterocephalus glaber

Naked mole-rat colonies are societies with a high reproductive skew, breeding being restricted to one dominant female (the 'queen') and 1-3 males. Other colony members of both sexes are reproductively suppressed. Experimental removal of breeding males allowed us to investigate the relationship between urinary testosterone and cortisol, dominance rank, and male reproductive status. Dominance rank was strongly correlated with body weight, age, and urinary testosterone titres in males. No relationship between urinary cortisol levels and male reproductive status or dominance was found. Breeding males were among the highest-ranking, heaviest and oldest males in their respective colonies, and were succeeded by other high-ranking, large, old colony males. In contrast to females, no evidence of competition over breeding status was observed among males. Male-male agonism was low both before and after removal of breeders and mate guarding was not observed. The lower reproductive skew for males compared with female skew or queen control over male reproduction may explain why males compete less strongly than females over breeding status after removal of same-sexed breeders.     

Aggression in male mice lacking functional estrogen receptor α.

Estrogen receptor alpha knockout (ERαKO) male mice fail to display sexual behavior. The authors hypothesized that ERαKOs require higher testosterone (T) concentrations than wild-type (WT) males to exhibit copulatory behavior. Increasing T stimulated sexual behavior and preference for females in WT males but failed to do so in ERαKOs. However, T did induce female-directed aggression in ERαKOs. In aggression tests, WT residents selectively attacked T-treated male intruders. ERαKO residents attacked female, T-treated male, and estrogen-treated male intruders equally. Increased access to olfactory cues prior to direct contact reduced overall aggression in ERαKO versus WT males but did not cause ERαKOs to differentially attack male and female opponents. Results suggest that ERα is essential for normal social behavior, perhaps via processing of chemoinvestigatory cues, which are required to discriminate males from females. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Primer on medical decision analysis: Part 2--Building a tree

Observations were made on four captive breeding groups of rhesus monkeys in order to measure hormonal, behavioral, and genital changes in adolescent males during the annual mating season. Three questions were addressed with regard to possible effects of social environment upon reproductive maturation: (1) Does male agonistic rank influence adolescent development? (2) Does affiliation between adolescent males and adult females during the mating season influence the males' reproductive development? (3) Does maternal rank exert any effect upon reproductive maturation in adolescent sons? In many (but not all) cases male rank was positively correlated with circulating testosterone and testes weights during the mating season. Affiliative behavior (allogrooming and sexual interactions) between adolescents and adult females in their social groups bore no relationship to the degree of reproductive maturation in males. Mounts involving intromission were infrequent, but sons of high-ranking mothers gained significantly more intromissions than sons of lower-ranking females. Maternal rank was also found to correlate with circulating testosterone levels, testes weights, growth of the baculum (os penis), and maintenance of body weight in adolescent sons during the mating season. By contrast, levels of beta-endorphin in the cerebrospinal fluid of adolescent males did not correlate with social rank, testosterone levels, or genital development. These findings point to possible effects of maternal rank, as well as intermale agonistic rank, in determining reproductive maturation during adolescence in the male rhesus monkey.     

Effects of altering testosterone in early infancy on social behaviour in captive yearling rhesus monkeys

Thirteen male and twenty female rhesus monkeys (Macaca mulatta), aged 9-12 months, living as members of long term captive social groups, were observed in order to quantify sex differences in a variety of behaviour patterns. Six males had been treated with a GnRH agonist (Meterelin: M) during their first six postnatal months, in order to block the surge of testosterone which occurs at this time. Ten females had been treated with testosterone (T) during their first six months, in order to mimic the postnatal T surge seen in males. The remaining 7 males and 10 females acted as control subjects. Marked sex differences were measured in frequencies of play and socio-sexual behaviour in these juvenile monkeys. However, neither M nor T treatments produced any significant changes in frequencies of these behaviour patterns. Although M-treated males showed a tendency (p < 0.1) to groom others for longer periods than control males, and control females tended to spend more time alone than T-treated females, we were unable to measure any significant (p < 0.05) effects of either M- or T-treatment upon affiliative behaviour in juvenile rhesus monkeys. We conclude, therefore, that the postnatal T surge in male rhesus monkeys does not affect development of sexually dimorphic and associated patterns of behaviour. Presumably, organisational effects of T upon these behaviour patterns must be completed before birth in this species.     

Diagnosing pregnancy in free-ranging elk using fecal steroid metabolites

We validated fecal metabolite analysis as a noninvasive means of diagnosing pregnancy in uncaptured, free-ranging Rocky Mountain elk (Cervus elaphus nelsoni). During November 1991, we collected blood samples from 21 radiocollared, 1- to 10-year-old female elk in Yellowstone National Park, Wyoming (USA), and determined their pregnancy status by radioimmunoassay of serum pregnancy specific protein B and serum progesterone concentrations. From December 1991 through April 1992, we collected three to 12 fecal samples from each collared elk and measured the concentration of estrone conjugates, pregnanediol-3-glucuronide, and free progesterone by enzyme immunoassays. We also evaluated fecal samples from 10 unmarked male and eight calf elk. Pregnant females had significantly (P < 0.001) higher concentrations of all three fecal metabolites than nonpregnant animals, especially later in gestation (March to April). We developed all possible combinations of univariate, bivariate, and multivariate discriminant function analysis models to determine those variables most useful in predicting memberships of pregnant versus nonpregnant elk during the March to April time-period. We validated each model by applying the classification functions to 11 pregnant and eight nonpregnant elk that were not included in the development of the original models. Accuracy of the discriminant function analysis models ranged from 57 to 84%, with the univariate model based on pregnanediol-3-glucuronide concentration providing the highest classification. Fecal metabolite analysis will enable biologists to noninvasively assess the pregnancy status of elk, especially when diagnoses are based upon multiple samples collected between mid-March and mid-April.     

Carcinoembryonic antigen in diagnosis and monitoring of colorectal cancer]

Female SJL mice are more susceptible than male mice to experimental autoimmune encephalomyelitis (EAE) induced by myelin basic protein (MBP)-specific T lymphocytes. In the present study, we examined mechanisms involved in this gender-related difference in disease susceptibility. MBP-specific T lymphocytes derived from spleens of males during the effector phase of adoptive EAE produced significantly higher levels of IL-10, an anti-inflammatory cytokine in EAE. A protective effect of testosterone was then shown. Females implanted with dihydrotestosterone pellets demonstrated a significantly less severe course of EAE as compared with females implanted with placebo pellets. Finally, MBP-specific T lymphocytes derived from dihydrotestosterone-implanted females produced significantly higher levels of IL-10 than those from placebo. Together these data indicate that testosterone exerts a protective effect in EAE that is mediated at least in part by enhanced production of IL-10 by autoantigen-specific T lymphocytes.     

Maternal effects on the development of social rank and immunity trade-offs in male laboratory mice (Mus musculus)

Social status in randomly constituted groups of male CFLP mice was predictable from early suckling behaviour and rate of weight gain in natal litters. High-ranking males were those that had suckled on more anterior teats and gained weight more quickly. Rank was not predicted by any measures of sibling interaction or hormone (testosterone, corticosterone) concentration. Aggressiveness in eventual high-rankers was associated negatively with the proportion of males in the litter at birth and the amount of maternal attention received. Aggressive social relationships within natal litters did not predict polarized rank relationships in randomized groups. Nevertheless, while still in their natal litters, and in the absence of aggressive rank relationships, eventual rank categories showed the same difference in modulation of testosterone concentration in relation to current immunocompetence (low-rankers modulating, high-rankers not), as has repeatedly been found in randomized groups by earlier studies. The role of maternal condition in determining rank-related life-history development in male mice is discussed.     

Glomerular basement membrane thickness in primary diffuse IgA nephropathy: ultrastructural morphometric analysis

In the male lesser mouse lemur (Microcebus murinus), a polygamous long-day breeder of which the life span may reach 12-14 years, the effects of aging on socio-sexual relationships were studied on 44 captive animals of various ages. In this primate, new dominance relationships must be established at the beginning of each breeding season. During the breeding season induced by exposure to artificial long days, preoestrous females were introduced into cages of paired males to elicit sexual competition. Sexual behaviors, social interactions through chemical signals, and dominance relationships were recorded in paired males either of similar age (young or aged pairs), or of mixed ages. In all pairs, competition for priority access to females always occurred and dominance relationships were established unrelated to body weight. Although aged animals exhibited significantly less number of sexual and aggressive behaviors, they outranked younger males excepted when reaching oldest age. Independent of male's age, the typical pattern of seasonal rhythm of testosterone was observed, but aged males demonstrated a significant reduction in mean hormonal levels (25.5 +/- 2.8 ng/mL, n = 8) compared to young animals (50 +/- 2.7 ng/mL, n = 8). Moreover, their hormonal response to photoperiod was phase-shifted leading to reduced testosterone values when females entered oestrus. Despite the fact that testosterone levels and sexual behaviors decreased with aging in this primate, older males reached a dominant position, increasing thus their reproductive success.     

Activation of the immune–endocrine system with lipopolysaccharide reduces affiliative behaviors in voles.

In Experiment 1, individually housed male meadow voles (Microtus pennsylvanicus) and prairie voles (Microtus ochrogaster) were injected with lipopolysaccharide (LPS) and exhibited the expected decrease in testosterone and increase in corticosterone and interleukin- 1β concentrations 3 hr later, indicating activation of the endocrine and immune systems. In Experiment 2, LPS- and saline-injected males were tethered in a 3-chamber partner preference apparatus. The time females spent in each chamber with a male, as well as the amount of time spent in social contact, was monitored. Female prairie voles, but not meadow voles, spent more time in the chamber with saline- than with LPS-injected males. LPS-injected male prairie and meadow voles engaged in less social contact with female conspecifics than did saline-injected males. These data suggest that LPS modifies physiology and behavior in male voles and that females may use these changes to discriminate healthy from potentially infected males. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Photoperiodic and endocrine control of social proximity behavior in male Japanese quail (Coturnix coturnix japonica).

Experiment 1 demonstrated that the social proximity behavior of male Japanese quail declines significantly when photostimulation is restricted to 2 hr daily, but can be restored by reinstituting the normal schedule. Changes in the photoperiod produced corresponding changes in the size of the cloacal gland, an androgen-dependent organ. The low levels of social proximity behavior and cloacal gland size of males maintained on short daily exposures to light also could be reversed by sc implants of testosterone (Experiment 2), and this recovery was to some extent sensitive to testosterone dose (Experiment 3). The present studies indicate that social proximity behavior in male Japanese quail is androgen dependent and provide a behavioral assay for neurohormonal studies of sexual behavior that does not depend on brief phasic responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Monthly measures of salivary testosterone predict sexual activity in adolescent males

Strong relationships between one-time serum testosterone (T) measures and sexual activity have been demonstrated in cross-sectional analyses of adolescent males. However, a subsequent longitudinal study of a separate adolescent sample, using semiannual plasma measures, failed to replicate cross-sectional findings. The present study reexamined the relationship between T and sexual activity using more frequently collected measures of salivary T and behavior. Saliva samples and weekly behavior checklists were collected over a 2-year period from the same panel sample of males on which semiannual analyses were based. Saliva samples representing measures approximately every fourth week of study participation were selected for T assay. The association between these monthly salivary T measures and weekly reports of incidents of sexual activity was assessed with repeated measures analyses. Higher levels of salivary T were significantly associated with an increasing hazard of coital initiation, and with more frequent coital and noncoital activity. Within-individual change analyses demonstrated that increases in salivary T were associated with increased sexual activity. Comparisons of models that varied specimen type, schedule of T measurement, and type of behavioral report indicated that all three factors contribute to the varying magnitude of hormone/behavior relationships that are demonstrated. These findings are consistent with a biosocial model of adolescent sexual development that pubertal changes in T are a causal factor in the timing of sexual initiation and the frequency of activity during adolescence.     

Decreased testosterone levels and accelerated extinction of a conditioned taste aversion in fluid-deprived male rats.

The hypothesis that fluid deprivation accelerates extinction of a conditioned taste aversion in male Sprague-Dawley-derived rats by reducing serum testosterone levels was tested. Serum testosterone levels were found to be lower in fluid-deprived males than in nondeprived males (Exps 1 and 2). Exogenous testosterone treatment that results in high physiological levels of serum testosterone slowed the extinction of fluid-deprived gonadectomized males to rates comparable with those of nondeprived sham males (Exp 3). It was noted, however, that testosterone treatment was less effective in slowing extinction in fluid-deprived gonadectomized males than in nondeprived gonadectomized males even though the serum testosterone levels were the same (Exps 3 and 4). These results provide strong support for the original hypothesis, but they suggest that fluid deprivation also reduces sensitivity to testosterone. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Androgen regulation of hypothalamic neurons containing gonadotropin-releasing hormone in a cichlid fish: integration with social cues

Reproduction in vertebrates is regulated by internal signals such as hormone levels and by external signals such as social interactions. In an African cichlid fish, Haplochromis burtoni, the effect of social interactions is evident in the hypothalamo-pituitary-gonadal (HPG) axis of males. Territorial males, characterized by aggressive and reproductive activity, have significantly larger hypothalamic gonadotropin-releasing hormone (GnRH)-containing neurons and larger testes than nonterritorial males. Furthermore, a switch in the social status of an adult male causes a corresponding change in GnRH neuron size and testis size. Here we show that the GnRH-containing neurons in the hypothalamus of adult territorial males are also influenced by gonadal hormones. Castration of territorial males caused GnRH neurons to increase in size. This neuronal hypertrophy in castrated animals was prevented either by testosterone (T) or 11-ketotestosterone (KT) treatment. Estradiol (E2) treatment did not reduce GnRH cell size in castrated animals. These results suggest that androgens reduce the size of GnRH cells through negative feedback. Since E2 had no effect, androgen influence on GnRH cell size appears to be independent of aromatization. These data are consistent with the hypothesis that the setpoint for hypothalamic GnRH cell size is determined by social cues and that this setpoint is maintained by negative feedback from gonadal androgens.     

Muscle strength and hormonal levels in adolescents: gender related differences

The purpose of the present investigation was to study muscle strength in adolescents and its relationship to serum levels of testosterone and growth hormone in both genders. Thirty active adolescents (15 boys; age range 11 -12 y/o) participated in the first study. Isokinetic muscle strength of the dominant knee extensors (KE) was determined at 0, 12, 20, 30, 120, 180 and 240 deg/sec using a Cybex 340 dynamometer. The assessment of pubertal status was accomplished using the criteria of Tanner. Serum levels of total testosterone (T) and growth hormone (GH) were determined using radioimmunoassay techniques. Boys had higher (p< 0.001) T levels but no differences in muscle strength were detected between genders. Fifty-seven additional subjects representing three age groups (11-12 y/o, n=18; 13-14, n=21; 17-18, n=18) participated in the second study. A significant increase in peak torque (absolute and corrected for body weight) with age was observed in both genders. There were no significant gender differences in strength for the two youngest age groups, but boys were stronger than girls in the oldest age group (group 3). Testosterone and GH levels increased with age in boys but not in girls. Gender related differences in T were found in groups 2 and 3. A positive correlation (r=0,64 boys; r=0.46 girls) between testosterone levels and absolute muscle strength was seen in both genders. Our results suggest that increases in anabolic hormones precede muscle strength gains in adolescent males. In addition, gender related differences in muscle strength during adolescents cannot be explained solely on the basis of difference in body size or T levels.     

Male traits, mating tactics and reproductive success in the buff-breasted sandpiper, Tryngites subruficollis

Buff-breasted sandpipers use a variety of mating tactics to acquire mates, including remaining at a single lek for most of the breeding season, attending multiple leks during the season, displaying solitarily or displaying both on leks and solitarily. We found that differences in body size, body condition, fluctuating asymmetry scores, wing coloration, territory location and behaviour (attraction, solicitation and agonistic) did not explain the observed variation in mating tactics used by males. Which males abandoned versus returned to leks was also not related to morphology or behaviour, and there was no tendency for males to join leks that were larger or smaller than the lek they abandoned. These results suggest that male desertion of leks was not dependent on a male's characteristics nor on the size of the lek he was presently attending. Males did join leks with larger males than their previous lek, perhaps to mate with females attracted to these larger 'hotshot' males. Males at both leks and solitary sites successfully mated. Lek tenure did not affect mating success, although lekking males appeared to mate more frequently than solitary males. Courtship disruption and to a lesser extent, female mimicry, were effective at preventing females from mating at leks, and may offer a partial explanation for female mating off leks. Our analysis that combined all males together within a year (regardless of mating tactic) indicated that males that attended leks for longer periods of time and that had fewer wing spots were significantly more likely to mate. Given some evidence that wing spotting declines with age, and that females inspect male underwings during courtship, the latter result suggests that female choice may play some role in determining male success. We suggest that male buff-breasted sandpipers may use alternative mating tactics more readily than males in other 'classic' lek-breeding species because: (1) unpredictable breeding conditions in this species' high arctic breeding range leads to low lek stability, which in turn hinders mate selection mechanisms mediated by male dominance and female choice; and (2) males are not constrained by morphological markings that indicate status or sex. Both characteristics may reduce the reproductive benefits associated with males adopting one mating tactic and result in a sort of scramble competition in which males switch between tactics as local conditions change.Copyright 1998 The Association for the Study of Animal Behaviour     

Psoralens percutaneous permeation across the human whole skin and the epidermis in respect to their polarity (in vitro study)

The vasopressin (VP)-containing projections from the cells of the bed nucleus of the stria terminalis to the lateral septum (LS) are sexually dimorphic and dependent on gonadal steroids. Recently, the difference in VP distribution found among both sexes was also demonstrated in male mice genetically selected for different levels of intermale aggression. In the present study we examined whether this differential VP distribution in males also exists in an outbred strain of wild-type rats. After the animals were tested for their level of aggression, the VP content and the fiber density of the LS were measured using radioimmunoassay and immunocytochemistry, respectively. In addition, basal levels of plasma testosterone (T) were measured. Both biochemical data and immunocytochemical data revealed a negative correlation between VP and intermale aggression. Aggressive rats exhibited low levels of VP whereas intermediate and nonaggressive animals showed higher levels. Differences in adult levels of T were not found. The results are in accordance with the observations previously found in male mice, reconfirming the correlation between lateral septal VP and aggression.     

A cross-cultural comparison of behavior disturbance and suicidal behavior among psychiatrically hospitalized adolescents in Israel and the United States

This study examines sexual behavior, serotonin turnover in the central nervous system, and testosterone in free-ranging non-human primates. Study subjects were 33 young adult male rhesus macaques (Macaca mulatta) living in naturalistic social groups on a 475-acre South Carolina barrier island. Blood and cerebrospinal fluid (CSF) samples were obtained during random trappings, and the subjects were located for observation by radio telemetry. Quantitative behavioral samples totaling 203 observation hours were taken during two mating seasons (September through January) in 1994 and 1995. Control observations (65 h) on 13 subjects were also taken during the non-mating seasons in 1994 and 1995. The results indicate that CSF 5-hydroxyindoleacetic acid (5-HIAA), CSF testosterone, and plasma testosterone concentrations increase significantly during the mating season. During the mating season, there were significant increases in high intensity aggression, low intensity aggression, grooming behavior, and heterosexual mounting. In the mating season, CSF 5-HIAA was significantly correlated with several sociosexual behaviors: consorts per hour, heterosexual mounts per hour, and inseminations per hour. In contrast to previous findings from the non-mating season, CSF 5-HIAA was not correlated with any measures of aggression or sociality, although during consorting, CSF 5-HIAA was positively correlated with grooming. From these findings, we conclude that the lack of correlation between intense and severe aggression and CSF 5-HIAA in the mating season may reflect the use of high intensity aggression in 'normative' male-male competition over access to reproductively active females. We also conclude that CNS serotonin turnover is positively correlated with sexual competence, i.e. males with low CSF 5-HIAA concentrations are less sexually competent than males with higher concentrations.