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PubMed2006

The lunar cycle: effects on human and animal behavior and physiology.

Human and animal physiology are subject to seasonal, lunar, and circadian rhythms. Although the seasonal and circadian rhythms have been fairly well described, little is known about the effects of the lunar cycle on the behavior and physiology of humans and animals. The lunar cycle has an impact on human reproduction, in particular fertility, menstruation, and birth rate. Melatonin levels appear to correlate with the menstrual cycle. Admittance to hospitals and emergency units because of various causes (cardiovascular and acute coronary events, variceal hemorrhage, diarrhea, urinary retention) correlated with moon phases. In addition, other events associated with human behavior, such as traffic accidents, crimes, and suicides, appeared to be influenced by the lunar cycle. However, a number of reports find no correlation between the lunar cycle and human reproduction and admittance to clinics and emergency units. Animal studies revealed that the lunar cycle may affect hormonal changes early in phylogenesis (insects). In fish the lunar clock influences reproduction and involves the hypothalamus-pituitary-gonadal axis. In birds, the daily variations in melatonin and corticosterone disappear during full-moon days. The lunar cycle also exerts effects on laboratory rats with regard to taste sensitivity and the ultrastructure of pineal gland cells. Cyclic variations related to the moon's phases in the magnitude of the humoral immune response of mice to polivinylpyrrolidone and sheep erythrocytes were also described. It is suggested that melatonin and endogenous steroids may mediate the described cyclic alterations of physiological processes. The release of neurohormones may be triggered by the electromagnetic radiation and/or the gravitational pull of the moon. Although the exact mechanism of the moon's influence on humans and animals awaits further exploration, knowledge of this kind of biorhythm may be helpful in police surveillance, medical practice, and investigations involving laboratory animals.

Animals↗

PubMed1991

Neural structures associated with reproductive development and photoperiodic effects in male chicks (Gallus domesticus).

White Leghorn chicks given parasagittal knife cuts that isolated the hypothalamus from lateral connections displayed early maturation of the testes. When the operated chicks were subsequently exposed to a long-day photoperiod known to stimulate gonadal development, no additional increase in the size of the testes occurred. In contrast, controls demonstrated a marked development of the gonads that surpassed testes size of experimentals. An additional study was designed to determine whether the archistriatum, a telencephalic structure that has significant projections to the hypothalamus, may be involved in the earlier onset of puberty shown by knife-cut chicks. Three different sets of brain cuts were made that severed projections from the archistriatum to the hypothalamus. None of the knife cuts affected development of the gonads when the birds were examined six weeks after surgery. Two of the three sets of knife cuts, however, effected a significant reduction in food intake, and operated chicks also displayed a significantly lower body weight compared to controls (p less than 0.05).

Animals↗

PubMed2001

Influence of undegraded intake protein on reproductive performance of primiparous beef heifers maintained on stockpiled fescue pasture.

The objectives of this study were to evaluate the effects of pre- and postpartum undegraded intake protein (UIP) supplementation on body condition score (BCS), BW, calf weight, milk production, serum IGF-I concentrations, and postpartum interval in primiparous beef heifers (n = 44). Heifers were maintained on endophyte-free stockpiled tall fescue (11.7% CP, 38% ADF) and individually fed supplement daily beginning 60 d prepartum. Pre- and postpartum supplements provided 19.3% CP, 83.4% TDN (UIP); 14.1% CP, 84.1% TDN (Control); 21.5% CP, 81.5% TDN (UIP); and 14.6% CP, 81.4% TDN (Control); respectively. Blood meal (146 g/d) was the source of UIP. Six heifers were removed from the study due to calf loss unrelated to treatment; therefore, postpartum measurements are based on 19 animals per treatment. Statistical analyses using ANOVA and a split-plot design revealed no effects of treatment (P > 0.2) on BCS, BW, calf weight, milk production, or postpartum interval. There tended to be a treatment x time interaction on BCS (P < 0.09) with UIP heifers having higher BCS than Control at wk 5, 7, and 9 postpartum. There was a treatment x time interaction on serum IGF-I (P < 0.06) during the first 35 d postpartum. In UIP heifers, serum IGF-I was greater at calving compared with Control heifers (117.5 vs 92.4 ng/mL, respectively); however, these differences were not related to changes in BCS or BW. Although serum IGF-I concentrations were increased at calving in heifers receiving UIP, there were no treatment effects on postpartum interval (P > 0.7). During the first 30 d postpartum, IGF-I differed (P < 0.01) among heifers with postpartum intervals defined as short, < 50 d (128.9 ng/mL); medium, 51 to 65 d (115.2 ng/mL); and long, 66 to 130 d (52.9 ng/mL). When analyzed as a regression, a 1 ng/mL increase in IGF-I (UIP and Control heifers) at calving (P < 0.05) and throughout the postpartum period (P < 0.01) corresponded to a decrease in postpartum interval of 0.13 d. Based on the results of this study, the inclusion of UIP in diets for primiparous heifers and its effects on postpartum interval warrant further evaluation.

Animal Feed↗

PubMed1988

Peptidergic neurohormonal systems in the basal hypothalamus of the ferret and the mink: immunocytochemical study of variations during the annual reproductive cycle.

The hypothalamic systems secreting corticotropin-releasing hormone (CRF), somatostatin, oxytocin, vasopressin and luteinizing hormone-releasing hormone (LHRH) were characterized using immunochemistry, and variations were studied in relation to the recrudescence of testicular activity in the ferret and the mink, two species with opposite photoregulation of their annual reproductive cycles. Under the present conditions of study, the immunoreactivity of the CRF, somatostatin, and oxytocin systems showed no significant variation in either species. In contrast, in these two species, the immunoreactivity of the LHRH system varied considerably depending on the date of observation. The increase in the number and immunoreactivity of the LHRH-secreting neurons that occurred in November in the mink and in January in the ferret, is in agreement with previous results showing that the photoperiod plays an essential role in regulating the annual activity of the testis and that the photoperiodic environmental conditions required for the activation of the LHRH system differ between the species. Similarly, correlations could be found between an increase in immunoreactivity of the vasopressinergic axons projecting to the external median eminence and the recrudescence of testicular activity.

Animals↗

PubMed1992

New pathways in animal reproductive physiology frontiers and perspectives.

With the inrush of new data the recent clear division of neural, hormonal and immunological regulation has been seriously complicated. Both central and peripheral neural tissue produce over 30 neuropeptides, among which are many classic peptide hormones. A steroid biosynthetic pathway has been demonstrated in oligodendrocytes. However, the distribution and role of peptydoergic neurons within the reproductive system are only superficially known among farm animals. Neurons have receptors for many hormones and interleukins. Cells of the immune system, in addition to secretion of many interleukins and interferons, produce neuropeptides locally and they possess specific receptors for them as well. Till now, the interaction between the nervous, hormonal and immunological systems has not been taken into account while investigating the functions of ovarian follicles, the corpus luteum, oviduct and uterus. The penetration of blood and lymphatic vessels by hormones, neuropeptides and cytokins has not been taken into consideration also. The counter current transfer of many steroid and peptide hormones from ovarian venous and lymphatic effluent to arterial blood supplying the ovary and through arterial anastomoses of the oviduct and uterus has been hithero shown. It has been demonstrated that thanks to this system, arterial blood supplying the uterus and oviduct has, in physiological conditions, a much higher level of some steroid hormones such as progesterone and androstendione, 37% and 36% respectively, than in systemic blood. Recently, a powerful exchange system for resupplying hormones to the brain which is dependent on the phase of the estrous cycle, has been discovered. It has also been demonstrated that neuropeptides LH-RH, beta-endorphin and oxytocin as well as the steroid hormone progesterone, were counter current transferred from venous to arterial blood at the perihypophyseal cavernous sinus and carotid rete in sheep and gilts, but only during specific periods of reproductive activity. The mechanism of this process is still unknown. The role of peptydoergic neurons and cytokins in vascular permeability during hormone counter current transfer in the broad ligament vasculature, perihypophyseal cavernous sinus and carotid rete has not been investigated. It is suggested that progress in this area may change our point of view on many basic regulatory mechanisms involved in animal reproductive physiology.

Animals↗

PubMed2006

Analysis of the laying rhythm and reproductive traits of geese.

The aim of the performed investigations was to analyse the laying rhythm and reproductive traits of Kołuda white geese from the W11 reproduction strain and to determine the heritability of these traits as well as correlations between the laying rhythm traits and reproductive traits. The total number of geese participating in the experiment included 383 one-year old layers from the control flock (the first year of reproductive utilisation). The following traits characterizing the laying rhythm were assessed individually for each layer: the number of 2 and 3-egg clutches or more, length (in days) of 2- or more egg clutches as well as the length of intervals between the laid eggs during the entire laying period. The following reproductive traits were also assessed individually for each bird: age at sexual maturity, initial number of eggs (eggs laid during the period from January, 1st to April, 30th), number of eggs during the whole laying period, laying intensity (the total number of eggs x 100/length of the laying period in days) as well as the length of the reproductive period. It was found that Kołuda white geese laid most of their eggs (on average 70.2%) singly and not in clutches. With regard to egg clutches, it was found that 2-egg clutches constituted 85.3% of eggs laid in clutches. Moderate or high variability of traits associated with the laying rhythm and reproduction were demonstrated. The observed moderate heritability of the laying rhythm traits indicate that they may be utilised in the selection programs for geese. On the other hand, the reported high, positive genetic correlation coefficients between the number of egg clutches and the initial and total egg number as well as laying intensity confirm the existence of interactions between these traits. This fact may be helpful in breeding programs for determining the optimal selection systems for geese.

Animals↗

PubMed2002

Effects of the aromatase inhibitor fadrozole on plasma sex steroid secretion, spermatogenesis and epididymis morphology in the lizard, Podarcis sicula.

Recently, increasing importance has been attached to the role of estrogens and their receptors in male reproduction, since they have been found to be abundant in the male reproductive tract. In the lizard, Podarcis sicula, a seasonal breeder, estrogens seem to be involved in the regulation of testicular activity. Particularly, it has been hypothesized that the block of spermatogenesis and the complete regression of the epididymis and other secondary sexual characters (SSCs) in autumn might be due to high estrogen levels. To investigate the role of estrogens in the reproductive process of male lizards, we utilized Fadrozole ((AI) [4-(5,6,7,8-tetrahydroimidazole [1,5-a] pyridin-5-yl)-benzonitrile monohydrochloride] (CGS 16949A)), a nonsteroidal inhibitor of aromatase, the enzyme involved in the aromatization of androgens to estrogens, evaluating its effects on plasma sex-hormone release, spermatogenesis and epididymis morphology. For this purpose, adult male lizards, captured during the autumnal recrudescence, were intraperitoneally injected with 0.5 microg and 5 microg/g/body weight of AI for 15 and 30 days. In the animals treated with the higher AI dose, estrogen levels decreased if compared to the control groups, whereas androgen levels increased. Furthermore, histologic sections of testes and epididymes showed that the 30-day treatment with AI-induced spermatogenesis resumption with release of sperms into the large lumen of the seminiferous tubules, and the epididymes appeared more developed with moderately secreting columnar canal cells. Therefore, it is proposed that failure of spermatogenesis in autumn might be due to high estrogen levels.

Animals↗

PubMed1988

Preservation of ovarian function and reproductive ability in patients with malignant ovarian tumors.

In a study designed to determine the merit of preserving ovarian function and childbearing capability in women with unilateral malignant ovarian tumors, the results of radical surgery (n = 86) and conservative surgery (n = 106) were compared. The mean length of survival was slightly but not significantly shorter following conservative surgery. There were 15 recurrences (14%) and 11 deaths among the conservative surgery group. The incidence of metastasis to the preserved ovary was high. In the most cases restoration of normal menses was fairly rapid after initial treatment, but this appeared to depend on whether or not chemotherapy was given postoperatively, the specific agents used, and the duration of their administration. Hypergonadotropic hypogonadism was the most common finding among the anovulatory patients. Sixteen women experienced a total of 27 pregnancies and 18 normal infants were born. Abortion was induced when conception occurred during a course of chemotherapy. These findings are encouraging in terms of the feasibility of preserving childbearing capability in ovarian cancer patients. However, they also underscore the necessity for close, long-term follow-up, which will be improved as new technologies become available.

Adult↗

PubMed1994

Age of mother at last birth in two historical populations.

This study uses sets of historical family reconstitutions from all of Quebec and from four villages of the Haut-Jura, France--first marriages of 2226 and 994 women, respectively--to investigate the physiological and social factors affecting age of mother at last birth before and during fertility transition. Age remained high throughout the period covered in Quebec, under 'natural' conditions, but showed a steady decline in the French material which extends to late 19th century generations practising family limitation. Age at marriage had no influence in Quebec; in France, however, women with the most surviving children at age 35 continued childbearing the latest. There was no link between biological ability to achieve a live birth, or in health status or aging rhythm, and age at last birth. Behaviour of mothers and daughters showed no relation. The variability in age at last birth thus appears to be random under natural conditions; with the onset of controls, social differences seem to influence not only the end of childbearing, but all aspects of behaviour governing final family size and child survival.

Age Factors↗

PubMed1989

Evidence for a light compensation of the inhibition of reproduction by low temperatures in the snail Helix aspersa. Ovotestis and albumen gland responsiveness to different conditions of photoperiods and temperatures.

Four combinations of photoperiods and temperatures have been tested on the reproduction and on the activity of the genital apparatus of the snail Helix aspersa. The results show some interaction between photoperiod and temperature and reveal a predominant effect of photoperiod that compensates for the negative effect of low temperatures. A combination of long day (LD, 18L:6D) and a temperature of 20 degrees C is the most favorable condition for egg-laying as well as for the effective functioning of the ovotestis and albumen gland. In contrast, during a short day (SD, 8L:16D), egg-laying is completely inhibited at 15 degrees C and partly inhibited at 20 degrees C; the differentiation of gametes can be observed in the ovotestis, but the mature oocytes are not released and thus they degenerate. In the albumen gland, an important synthetic activity is noticed, but cellular multiplication and the release of the secretory products decrease. These results suggest that short photoperiods induce inhibition of the (neuro)endocrine centers responsible for the control of both ovulation and egg-laying.

Animals↗

PubMed1990

Annual rhythm of human reproduction: II. Environmental correlations.

Annual rhythms of human conception rates (based on a worldwide selection of statistics) were correlated with photoperiod, monthly averages of daily hours of sunshine, minimum and maximum temperature, and humidity. Our results show for the first time on a global scale that photoperiod, as shown for many animals, may also influence the physiology of human reproduction. At higher latitudes, where changes in daylength are pronounced, a steep increase in human conceptions coincides with the vernal equinox. Temperature also appears to be a major influencing factor. Conception rates are above the annual mean at temperatures between 5 degrees and 20 degrees C, and temperature extremes decrease the probability of conceptions. In regions with cold winters and moderate summers, the number of conceptions correlates positively with temperature; close to the equator, where winters are more moderate than the hot summers, this correlation is negative. Regions with both hot summers and cold winters tend to have a bimodal conception rhythm. The influence of photoperiod is dominant before 1930, whereas the impact of temperature dominates in later years. With industrialization, people are increasingly shielded from both photoperiod (by indoor work) and temperature (by heating and air conditioning), which may explain the deseasonalization of the human conception rhythm. Photoperiod and temperature and the specific changes in their impact can account for several features of the annual human conception rhythm: latitude dependence, waveform, phase and amplitude, and their specific changes over time.

Climate↗

PubMed2005

Resumption of sexual relations following childbirth: norms, practices and reproductive health issues in Abidjan, Côte d'Ivoire.

Before modern contraceptive methods were available in developing countries, post-partum sexual abstinence formed the backbone of birth spacing. With the changes occurring in African societies, how has post-partum sexual abstinence been affected? We conducted an exploratory study in 2000-2001 in Abidjan, Côte d'Ivoire with 23 women and 19 men who were parents of small children. Breastfeeding remains widespread and prolonged. Resumption of sexual relations after delivery was a mean of 11 months. Post-partum sexual abstinence was only distantly related to the traditional lactation taboo. Women expressed fears that their partner would seek elsewhere if they delayed sexual relations too long, and the risk of early pregnancy. Abstinence remained the main way to space births, given low contraceptive use. Mothers generally decided when to wean a child. Men usually made the first move to resume sexual relations, though most women negotiated timing and some insisted on condom use. Provision of condoms post-partum can play a contraceptive role for married couples and protect against STIs/HIV in extra-marital relationships, which are frequent post-partum. The duration of post-partum abstinence is in fact unclear because irregular sex may happen early and become regular only later. Women need post-partum information and services that address these issues.

Adolescent↗

PubMed1991

Seasonal changes in plasma concentrations of immunoreactive inhibin and testicular activity in male Japanese monkeys.

Seasonal changes in plasma immunoreactive (ir-) inhibin, testosterone, LH, and FSH concentrations were examined in five sexually mature male Japanese monkeys (Macaca fuscata fuscata) housed indoors individually, to explore the reproductive cyclicity in the male. Blood samples were collected monthly throughout one year, and testicular size, semen volume, and number of sperm in the semen were ascertained at the same time in the same animals. Semen samples were obtained by penile electrostimulation. The results showed a clear seasonal increase in all parameters: plasma ir-inhibin, testosterone, testicular size, semen volume, and total number of sperm in the liquid portion of the semen during the autumn and winter months in synchrony with the natural breeding season. In contrast, plasma LH and FSH remained unchanged throughout the year, although plasma FSH tended to increase during the breeding season concomitant with an increase in plasma ir-inhibin. A significant positive correlation between FSH and ir-inhibin was observed in two of five monkeys. The positive correlations between plasma ir-inhibin and testicular activities during both the developing and regressing phases of the testicular cycle indicate that plasma ir-inhibin is a useful indicator of testicular activity as well as an indicator of Sertoli cell function in the Japanese monkey.

Animals↗

PubMed1985

Refractoriness to inhibitory day lengths initiates the breeding season of the Suffolk ewe.

Recent evidence indicates that the breeding season of the Suffolk ewe ends because of loss of response to a day length that was previously inductive. This condition of photorefractoriness could potentially also initiate reproduction, as is the case in several long-day breeding rodents. In this study we determined if ewes enter their breeding season because they become refractory to the long ambient photoperiods of late summer. On the summer solstice, 3 groups of ovariectomized ewes (n = 6) bearing s.c. Silastic implants of estradiol (OVX + E) were placed in different day length treatments: 1) natural photoperiod; 2) artificial photoperiod, stimulating natural day lengths; or 3) artificial photoperiod equivalent to that of the summer solstice (16.25L). Entry into the breeding season is associated with a striking (greater than 30-fold) increase in circulating levels of luteinizing hormone (LH). Timing of the onset of the breeding season was not delayed in ewes maintained on the summer solstice photoperiod; LH levels rose simultaneously in all groups. We conclude that ewes normally begin breeding not because they are actively driven to do so by decreasing or short days, but because they become refractory to prevailing long days. Because the pattern of circulating melatonin, which is known to transduce the photoperiodic message, remained entirely appropriate to day length, we believe that the mechanism responsible for photorefractoriness resides in the postpineal processing of the melatonin signal.

Animals↗

PubMed2005

A histological investigation of the maturation of the acorn worm, an inhabitant of the Sea of Japan, and a suggestion about the relationship between synchronized spawning/spermiation and the tidal level.

One species of Hemichordata, Balanoglossus misakiensis, is then acorn worm originally reported from the intertidal zone of the Miura Peninsula on the Pacific Ocean side of Japan. We histologically examined the reproductive cycle of the population of this species, which inhabits only the sublittoral zone in the Sea of Japan. Testes and ovaries began to develop at the beginning of May 2003 and were almost mature in the latter half of June in males and in the first half of July in females in the same year. Subsequently, spermiation and spawning followed in the latter half of July in males and in the first half of August in females. Progress in maturation appeared to be related to increases in the water temperature. Although some experiments were conducted in aquariums to identify the conditions responsible for the synchronization of the occurrence of spontaneous spawning/spermiation, no clues were obtained. During the experiments, however, 11, 2, and 4 individuals out of the 67 used achieved spawning/spermiation on separate days. The occurrence of spawning/spermiation in the laboratory corresponded to the latter half of the switch from high tide to low tide on those days. Also in the field, it was known that they released the gametes according to this specific schedule. Therefore, it was suggested that, in the Japan Sea population of this species, the tide level may be a condition for synchronized spawning/spermiation.

Animals↗

PubMedDate not supplied

Reproduction in the red deer female and the effect of oestrogens on the antler cycle and behaviour.

Red deer (Cervus elaphus) is a seasonally breeding mammal. The season of reproduction is probably regulated by photoperiod. The rut and the majority of conceptions occur in October. If hind is not allowed to mate the oestrus is repeated at an interval of about 13.5 days. In captivity the mating season is more prolonged and the calving season is extended. The length of gestation is about 235 days. The fat % of milk varies between 6.6 and 17.4. A hind in good condition may attain puberty as 16.5 month old. The smaller doses of stilboestrolum dipropionicum (S, 150-250 mg) induced mainly a female type of sexual behaviour or oestrus. The bigger and more prolonged administration of S (250-300 mg, given twice with a monthly interval) induced a strong male sexual behaviour e.g. roaring, chasing a hind in oestrus, mouting a hind in oestrus or a dummy sprinkled with pheromones and performance of an ejaculatory peak (M). During M the hind was in an almost vertical position and a single ejaculation of saliva was always observed. The artificially induced antlers of hinds without hormonal treatment became broken and their regrowth was very small. After S the velvet was always shed. After larger doses of S the casting was more delayed and the next antler growth was bigger.

Animals↗

PubMed2006

Growth rates, reproductive phenology, and pollination ecology of Espeletia grandiflora (Asteraceae), a giant Andean caulescent rosette.

From March 2001 to December 2002, we studied the reproductive phenology, pollination ecology, and growth rates of Espeletia grandiflora Humb. and Bonpl. (Asteraceae), a giant caulescent rosette from the Páramos of the Eastern Andes of Colombia. Espeletia grandiflora was found to be predominantly allogamous and strongly self-incompatible. Bumblebees (Bombus rubicundus and B. funebris) were the major pollinators of E. grandiflora, although moths, hummingbirds, flies, and beetles also visited flowers. Inflorescence development began in March and continued through August to September. Plants flowered for 30 - 96 days with a peak from the beginning of October through November. The percentage of flowering plants strongly differed among size classes and between both years. Seed dispersal occurred as early as September through May of the following year. The average absolute growth rate for juveniles and adults rate was 7.6 cm/year. Given the scarcity of floral visitors at high altitudes due to climatic conditions, we suggest that even small contributions from a wide range of pollinators might be advantageous for pollination of E. grandiflora. Long-term studies on different populations of E. grandiflora are required to determine if the high growth rates are representative, to quantify the variation in the flowering behavior within and among populations, and to establish if nocturnal pollination is a trait that is exclusive to our population of E. grandiflora.

Asteraceae↗

PubMed1996

Enhanced reproductive responses to melatonin in juvenile Siberian hamsters.

Reproductive responses to melatonin (Mel) exposure were assessed in male Siberian hamsters gestated in long (16 h light/day; 16L) or short (8 h light/day; 8L) day lengths (DLs). Hamsters were maintained in constant light beginning at 14 days of age (day 14) and were infused for 3 successive days beginning on day 18, 25, or 32 with long (12 h/day) or short (6 h/day) durations of Mel or saline. Two weeks later, testis and body weights were determined. Responsiveness to Mel was enhanced in hamsters beginning shortly after weaning and was influenced by photoperiodic history. Gonadal growth in 16L hamsters was inhibited by 12-h Mel infusions initiated on day 18 or day 25, but infusions initiated on day 32 were ineffective. Hamsters gestated in 8L were not responsive to Mel treatments initiated on day 18, but discriminated 12-h from 6-h infusions at day 25 and manifested reduced gonadal growth after 12-h Mel infusions on day 32. Hamsters born in 8L to dams judged as photoinsensitive to short DLs did not respond to 12-h infusions on day 32 as inhibitory signals. We propose that maternal Mel secretion provides juvenile males with a photoperiodic history, which allows them to compare gestational with early postweaning Mel signals and thereby program seasonally appropriate developmental trajectories.

Aging↗