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Sociodemographic, behavioral, and reproductive factors associated with weight gain in Chinese women.

OBJECTIVE: To examine whether certain sociodemographic, behavioral, and reproductive factors are associated with an increased weight gain in Chinese women. DESIGN: Baseline survey data, including recalled past weight and measured current weight, from an ongoing prospective cohort study conducted in Shanghai, China. SUBJECTS: The analytical sample included 75 039 nonpregnant women aged 40-70 y. MEASUREMENTS: Statistical associations between certain sociodemographic, behavioral, and reproductive factors and weight gain were evaluated using multiple linear and logistic regression models. RESULTS: Weight gain and waist-to-hip ratio (WHR) increased with age among pre- and postmenopausal women before age 55 y. Weight gain declined but WHR continued rising as aging among postmenopausal women over age 55 y. Lower education levels, more parity and earlier age at the first birth, and earlier menarcheal age were associated with a higher long-term weight gain and current body weight. CONCLUSION: Age, education levels, parity, age at the first live birth, and menarcheal age were associated with long-term weight gain in Chinese women. However, these results concerning weight gain are based on recalled past weight and should be interpreted with caution. Further studies are needed to clarify the association of weight gain with lifestyle factors suggested by this study.

Adult↗

Somatic, behavioral, and reproductive disturbances in mice following neonatal administration of sodium L-aspartate.

Sodium L-aspartate (ASP) was administered to neonatal mice according to an increasing dose schedule from Days 2--11 after birth. Adult ASP-treated animals showed large increases in body weight over controls along with stunted body length. The ASP group also showed decreases in locomotor and exploratory behavior. Reproductive dysfunction occurred in both female and male ASP-treated animals. Among treated animals, females had fewer pregnancies and smaller litters while males showed reduced fertility. Evidence of multiple endocrine dysfunction in ASP-treated animals was reflected by decreased pituitary, thyroid, ovaries and tested weights, along with delayed onset of puberty in females. These results demonstrate that sodium L-aspartate produces a syndrome similar to that seen following the administration of monosodium L-glutamate.

Animals↗

Ligand-independent activation of progestin receptors in sexual receptivity.

Ovarian steroid hormones, estradiol and progesterone, regulate cellular functions in the central nervous system, resulting in the alterations in physiology and reproductive behavior. One means by which steroid hormones exert their neural effects on reproductive behavior is via their intracellular receptors functioning as ligand-dependent transcription factors. Studies from our laboratory in the past few years have shown that in addition to their cognate ligands, neurotransmitters like dopamine can activate intracellular steroid receptors in a ligand-independent manner. Using biochemical and molecular approaches we have demonstrated that the effects of neurotransmitter dopamine, on reproductive behavior in female rats and mice, occur by means of cross talk between membrane receptors for dopamine and intracellular progestin receptors (PRs). In this article, our studies on the integration of intracellular signaling pathways leading to the activation of PRs and its impact on modulation of reproductive behavior are summarized.

Animals↗

The neural basis of motivated behavior.

A complete motivated or goal-oriented behavioral act can be viewed as consisting of initiation, procurement, and consummatory phases. In order to gain some insight into the organizing principles of neural circuitry that underlies the expression of motivated behavior, certain basic pathways thought to play an important role in two specific classes of such behavior, hypovolemic thirst and reproductive behavior, are reviewed. In both cases, humoral factors participate in the initiation phase, and their sites of action have been rather clearly defined. Circuitry underlying the procurement phase, which involves foraging behavior, is much more complex, but can be thought of as involving two fundamentally different systems, one concerned with the processing of specific sensory information and the production of refined motor responses, and the other concerned with modulating behavioral state. The former is associated primarily with the thalamocortical-lateral forebrain system whereas the latter is associated primarily with the medial forebrain system. Finally, evidence favoring the hypothesis that "biochemical switching" may take place in fixed neuroanatomical circuitry associated with ingestive and reproductive behaviors is reviewed.

Angiotensin II↗

Fos-like immunoreactivity in catecholaminergic brain nuclei after territorial behavior in free-living song sparrows.

The catecholaminergic cell groups of the brainstem play an important role in the regulation of motivated behavior, including reproductive behavior. In songbirds, these cell groups project to telencephalic nuclei involved in singing and contain steroid hormone receptors, implicating them in the seasonal regulation of song. Whether these nuclei are involved in the activation of song on a short-term, moment-to-moment basis is unknown. In this study, free-living male song sparrows (Melospiza melodia) were subjected to simulated territorial intrusion (STI), which stimulates territorial singing. The resulting fos-like immunoreactivity (FLI) was quantified in two HVc- and RA-projecting catecholaminergic regions of the brainstem: the area ventralis of Tsai (AVT) and the midbrain central gray (GCt). Males subjected to STI showed more FLI in both of these regions than control males. In addition, FLI in both nuclei was correlated positively with the number of songs sung in response to STI. The number of flights directed at the intruder was correlated with FLI in AVT but not GCt. These results suggest a role for AVT and GCt, and thus possibly catecholamines, in the regulation of territorial behavior in songbirds.

Agonistic Behavior↗

[Sex behavior and reproduction of farm animals].

The sexual behaviour of farm animals was followed up both at loose-pasture raising and under industrial conditions. It was studied in estrus, in the search for a sexual partner, with regard to the tolerance of the female animals for the males in the sexual act, with regard to the herd hierarchy, the intraspecies relationships, and the condition of dominance, aggressiveness, and subordination. The role is stated of the presence of male animals in the herd for the regular course of the sexual cycle, and the shortening and synchronization of the estrus. Discussed is also the importance of the artificial visual, sound, olfactory, tactile and other stimuli of the behaviour of the male breeding animals in substantiating the coitus and the proper semen production. It was found that the reproductive process is largely dependent on on the sexual reactions of the animals, which requires a proper knowledge with regard to the substantiation of each sexual cycle. Thus, it is stated, higher conception and fertility rates are to be expected. It was also established that under the conditions of industrial technologies of raising the number of behavioural reactions in their use was strongly reduced because of the lowered contact between the individual groups, while the practice of artificial insemination thoroughly rules out the contact between the male and female animals.

Animals↗

The significance of the nest-building of the nine-spined stickleback, Pungitius pungitius.

The reproductive behavior of the stickleback is unique and odd, occurring inevitably with nesting. However, upon investigation, it has been found that nesting is an obstacle to hatching. The author conducted a survey in the necessity of nesting behavior in the nine-spined stickleback, Pungitius pungitius, and reached following conclusion: For Pungitius pungitius, nesting is the means of communicating to descendants settlement at a fixed area where cold water flowed bountifully and the water temperature was constant. Pungitius pungitius has evolved a behavior pattern that involves settling where water temperature is uniform, without evolving physiologically or morphologically, thereby enabling Pungitius pungitius to adapt to the changes in environment.

Animals↗

Pheromones elicit equivalent levels of Fos-immunoreactivity in prepubertal and adult male Syrian hamsters.

Male reproductive behavior in the Syrian hamster is dependent on both pheromones from the female and the presence of gonadal steroid hormones. The pheromones are contained within female hamster vaginal secretions (FHVS) and stimulate anogenital investigation and mounting by the male. Administration of testosterone to castrated male hamsters facilitates anogenital investigation, mounts, and intromissions in adults, but elicits only anogenital investigation in prepubertal males. One hypothesis for why the full complement of reproductive behaviors is not activated by testosterone in prepubertal males is that the neural processing of pheromonal cues encountered during anogenital investigation is different in juveniles and adults. In the present experiment, we investigated the influence of sexual maturity on Fos expression in response to FHVS in the male Syrian hamster. We predicted a greater increase in Fos-immunoreactivity after exposure to FHVS within the neural circuit mediating male reproductive behaviors in adult compared to prepubertal males. Intact adult and prepubertal males were exposed to either a clean cotton swab or a swab containing FHVS. We found that, compared to animals exposed to a clean cotton swab, both prepubertal and adult males exposed to FHVS have a greater amount of Fos-immunoreactivity within several brain nuclei comprising the neural circuit mediating male reproductive behavior. Furthermore, this Fos response was equivalent in the two age groups. These results suggest that the inability of the prepubertal male hamster to perform the full repertoire of male reproductive behaviors is not due to a lack of a neuronal activation in response to the pheromonal cues present in FHVS.

Age Factors↗

Organizational effects of estrogens on brain vasotocin and sexual behavior in quail.

Reproductive behavior is sexually differentiated in quail: The male-typical copulatory behavior is never observed in females even after treatment with high doses of testosterone (T). This sex difference in behavioral responsiveness to T is organized during the embryonic period by the exposure of female embryo to estrogens. We showed recently that the sexually dimorphic medial preoptic nucleus (POM), a structure that plays a key role in the activation of male copulatory behavior, is innervated by a dense steroid-sensitive network of vasotocin-immunoreactive (VT-ir) fibers in male quail This innervation is almost completely absent in the female POM and is not induced by a chronic treatment with T, suggesting that this neurochemical difference could be organizational in nature. This idea was tested by injecting fertilized quail eggs of both sexes on day 9 of incubation with either estradiol benzoate (EB) (25 microg, a treatment that suppresses the capacity to show copulatory behavior in adulthood) or the aromatase inhibitor R76713 (10 microg, a treatment that makes adult females behaviorally responsive to T), or with the solvents as a control (C). At 3 weeks posthatch, all subjects were gonadectomized and later implanted with Silastic capsules filled with T. Two weeks later, all birds were perfused and brain sections were processed for VT immunocytochemistry. Despite the similarity of the adult endocrine conditions of the subjects (all were gonadectomized and treated with T Silastic implants providing the same plasma level of steroid to all subjects), major qualitative differences were observed in the density of VT-ir structures in the POM of the different groups. Dense immunoreactive structures (fibers and a few cells) were observed in the POM of C males but not females; EB males had completely lost this immunoreactivity (and lost the capacity to display copulatory behavior); and, conversely, R76713 females displayed a male-typical VT-ir system in the nucleus (and also high levels of copulatory behavior). Similar changes in immunoreactivity were seen in the nucleus of the stria terminalis and in the lateral septum (VT-ir fibers only in this case) but not in the magnocellular vasotocinergic system. These neurochemical changes closely parallel the effects of the embryonic treatments on male copulatory behavior. The vasotocinergic system of the POM can therefore be considered an accurate marker of the sexual differentiation of brain circuits mediating this behavior.

Analysis of Variance↗

Gonadal steroids vary with reproductive stage in a tropically breeding female anuran.

Tropically breeding anurans that require heavy rainfall in order to reproduce are subject to favorable breeding conditions that are sporadic. Although there is an increased probability of rain during the rainy season, the probability of local rainfall is unpredictable and this may influence female anuran reproductive strategies. The female túngara frog, a neotropical frog that requires standing water to breed, maintains readiness to breed at any time via asynchronous oogenesis. Although females constantly produce and maintain oocytes during the breeding season, this study shows that they have cyclic fluctuations in gonadal hormone levels. Plasma levels of estrogen significantly change during three reproductive stages within a single reproductive cycle (P=0.03), as do plasma levels of progesterone and androgen (P<0.001 and P=0.001, respectively). Furthermore, elevation in plasma estrogen and progesterone concentrations occurs during the same reproductive stage in which it has been reported that females display the maximum frequency of reproductive behaviors, the amplexed stage. Androgen levels, however, are elevated prior to the reproductive stage in which females display maximal reproductive behavior, that is, the unamplexed stage. Our study suggests that the pattern of gonadal hormone fluctuation in a tropically breeding female anuran is similar to the classic paradigm in which there is a temporal relationship between the appearance of reproductive hormones and reproductive behaviors.

Androgens↗

Comparison of lethality, reproduction, and behavior as toxicological endpoints in the nematode Caenorhabditis elegans.

This study describes a new approach for assessing behavioral changes following toxicant exposure and compares the method to other common endpoints used in environmental toxicology. The nematode Caenorhabditis elegans was exposed to a range of ethanol concentrations to determine its effect on survival, reproduction and behavior. Each endpoint was evaluated for its sensitivity by comparing LC50, RC50 (concentration at which there is a 50% reduction in number of offspring as compared to controls), and BC50 (concentration at which there is a 50% reduction in movement as compared to controls) values for ethanol exposure. Worms showed 24-h lethality at concentrations of ethanol in the range of 83 g/L to 99 g/L. Reproduction in C. elegans was estimated by counting the number of off-spring after 3 d of exposure, which decreased with the increase in ethanol concentration from 8 g/L to 71 g/L. Behavior was quantified by using a new computer tracking method, which can simultaneously assess hundreds of nematodes and provides several behavioral parameters in real time. Worms showed some hyperactivity (increased movement) at very low ethanol concentrations (0.8 g/L and 2.4 g/L) and a decrease in movement at higher ethanol concentrations (4 g/L to 40 g/L). A comparison for sensitivity between the three endpoints was performed. Behavior and reproduction responses were found to be similar and, as expected, both are much more sensitive indicators of toxicity than lethality. The advantages and disadvantages of the computer tracking system are discussed.

Animals↗

Annual cycle of plasma testosterone in male copperheads, Agkistrodon contortrix (Serpentes, Viperidae): relationship to timing of spermatogenesis, mating, and agonistic behavior.

Reproductive cycles of the majority of squamate reptiles remain undescribed. Few studies are available on seasonal patterns of circulating steroid hormones in snakes. The goal of this study was to document the annual cycle of plasma testosterone (T) in male copperheads Agkistrodon contortrix, a North American pitviper (Serpentes, Viperidae). Two experimental conditions were used in this laboratory study. One condition (repeat-test group) consisted of 10 adult males that were sampled once each month for 11 months. The other condition (single-test groups) consisted of 10 groups each with 5 males (N = 50), and each male was tested a single time. The single-test condition was used to evaluate whether or not repeated handling and sampling affected T levels. The study was conducted from February-December, 1992. A well-defined seasonal pattern of plasma T levels was detected; patterns were similar under both experimental conditions with the exception that the repeat-test group had slightly lower levels. Levels of T were lowest (baseline) in April-May, increased in early summer (June), and were highest in late summer (August). Thereafter, T levels declined up to the time of hibernation (early November) and changed little during hibernation (November-January). Upon emergence from hibernation in late winter (February), T levels increased sharply from February to March and then decreased from March to April. The results are discussed in the context of timing of spermatogenesis, mating, and male agonistic behavior.

Agkistrodon↗

Estrogen-behavior correlates in the reproductive physiology and behavior of the ruffed lemur (Lemur variegatus).

The animal subjects of this study consisted of seven male-female pairs, living an open-air, off-exhibit area of the San Diego Zoo. Daily urinary estrogen levels in each of five females were measured and daily behavioral observations of the seven pairs were made. Behavioral patterns aligned by objectively determined, discrete physiologic events were analyzed to determine their temporal correlation to changes in estrogen excretion. The data indicate that approximately one-sixth of the female behaviors and one-third of the male behaviors sampled were significantly correlated to urinary estrogen levels in the females (P less than 0.05-0.005). In addition, both attractivity and receptivity were distinguishable and their component behaviors in males and females were found to be related to the estrogen profile. Proceptivity, however, was only weakly identified and its description in this sample population was ambiguous. Mating was observed to occur exclusively on 1 day, presumably the day of ovulation.

Animals↗

Lycium barbarum polysaccharides: Protective effects against heat-induced damage of rat testes and H2O2-induced DNA damage in mouse testicular cells and beneficial effect on sexual behavior and reproductive function of hemicastrated rats.

Lycium barbarum, a famous Chinese medicinal herb, has a long history of use as a traditional remedy for male infertility. Polysaccharides are the most important functional constituent in L. barbarum fruits. We systematically investigated the effect of L. barbarum polysaccharides (LBP) on rat testis damage induced by a physical factor (43 degrees C heat exposure), on DNA damage of mouse testicular cells induced by a chemical factor (H2O2), and on sexual behavior and reproductive function of hemicastrated male rats. The results showed that LBP provided a protective effect against the testicular tissue damage induced by heat exposure. When compared with negative control, a suitable concentration of LBP significantly increased testis and epididymis weights, improved superoxide dismutase (SOD) activity, and raised sexual hormone levels in the damaged rat testes. LBP had a dose-dependent protective effect against DNA oxidative damage of mouse testicular cells induced by H2O2. LBP improved the copulatory performance and reproductive function of hemicastrated male rats, such as shortened penis erection latency and mount latency, regulated secretion of sexual hormones and increased hormone levels, raised accessory sexual organ weights, and improved sperm quantity and quality. The present findings support the folk reputation of L. barbarum fruits as an aphrodisiac and fertility-facilitating agent, and provide scientific evidence for a basis for the extensive use of L. barbarum fruits as a traditional remedy for male infertility in China.

Animals↗

Effects of sublethal exposure to boric acid sugar bait on adult survival, host-seeking, bloodfeeding behavior, and reproduction of Stegomyia albopicta.

Effects of sublethal exposure to 0.1% boric acid sugar bait on adult survival, host-seeking, bloodfeeding behavior, and reproduction of Stegomyia albopicta were studied in the laboratory. Survival of males as well as females was significantly reduced when exposed to the bait, compared to control adults. The host-seeking and bloodfeeding activities in the baited females decreased, but the mean duration of blood engorgement (probing to voluntary withdrawal of proboscis) was not significantly different between the baited and control females. The landing and biting rates (human forearm) were significantly reduced in the baited females compared to nonbaited controls. Fecundity and fertility (based on number of laid eggs per female and percentage egg hatch, respectively) in the baited females were significantly reduced, and ovarian development was retarded. Sublethal exposure to sugar-based boric acid bait has the potential to reduce adult populations of St. albopicta.

Animals↗

Perinatal astemizole exposure in the rat throughout gestation: long-term behavioral and anatomic effects associated with reproduction.

Astemizole (ATZ), a non-sedative antihistamine, which antagonize histamine at the level of H1 receptor, was administered daily to female Wistar rats as a 10-mg/kg dose throughout pregnancy. ATZ exposure reduced offspring body weight and delayed the pinna detachment and startle reflex without any modification of dams body weight during gestation. Long-term disruption of male reproductive behavior was seen in experimental animals, whereas female sexual behavior was not modified. In addition, no motor alterations were observed in female or males in adulthood. Testis wet weight was reduced, but no modifications were detected in vasa deferentia or seminal vesicle. We proposed that ATZ administration during pregnancy causes several effects mainly of a sexual nature by interfering either with the hormonal mechanism involved in the central nervous system masculinization or by a direct action of the drug on pups during the development.

Animals↗