Effect of platelet-activating factor on food intake, cloacal temperature, voluntary activity and crop emptying rate in chicks

Platelet-activating factor (PAF) plays a significant role in several leucocyte functions, including platelet aggregation and inflammation. Additionally, PAF has a role in the behavioral and physiological changes in mammals. However, the effect of PAF has not been well studied in birds. Therefore, the study aimed to determine if PAF affects feeding behavior, voluntary activity, cloacal temperature, and feed passage through the digestive tract in chicks (Gallus gallus). We also studied the involvement of PAF in the innate immune system induced by lipopolysaccharide (LPS), a cell wall component of gram-negative bacteria. Both intraperitoneal (IP) and intracerebroventricular (ICV) injections of PAF significantly decreased food intake. IP injection of PAF significantly decreased voluntary activity and slowed the feed passage from the crop, whereas ICV injection had no effect. Conversely, ICV injection of PAF significantly increased the cloacal temperature, but IP injection had no effect. The IP injection of LPS significantly reduced the mRNA expression of lysophosphatidylcholine acyltransferase 2, an enzyme responsible for PAF production in the heart and pancreas. On the other hand, LPS significantly increased the mRNA expression of the PAF receptor in the peripheral organs. The present study shows that PAF influences behavioral and physiological responses and is related to the response against bacterial infections in chicks.

Proteinaceous Pheromone Homologs Identified from the Cloacal Gland Transcriptome of a Male Axolotl, Ambystoma mexicanum

Pheromones play an important role in modifying vertebrate behavior, especially during courtship and mating. Courtship behavior in urodele amphibians often includes female exposure to secretions from the cloacal gland, as well as other scent glands. The first vertebrate proteinaceous pheromone discovered, the decapeptide sodefrin, is a female attracting pheromone secreted by the cloacal gland of male Cynops pyrrhogaster. Other proteinaceous pheromones in salamanders have been shown to elicit responses from females towards conspecific males. The presence and levels of expression of proteinaceous pheromones have not been identified in the family Ambystomatidae, which includes several important research models. The objective of this research was therefore to identify putative proteinaceous pheromones from male axolotls, Ambystoma mexicanum, as well as their relative expression levels. The results indicate that axolotls possess two different forms of sodefrin precursor-like factor (alpha and beta), as well as a putative ortholog of plethodontid modulating factor. The beta form of sodefrin precursor-like factor was amongst the most highly expressed transcripts within the cloacal gland. The ortholog of plethodontid modulating factor was expressed at a level equivalent to the beta sodefrin precursor-like factor. The results are from a single male axolotl; therefore, we are unable to assess how representative our results may be. Nevertheless, the presence of these highly expressed proteinaceous pheromones suggests that male axolotls use multiple chemical cues to attract female conspecifics. Behavioral assays would indicate whether the putative protein pheromones elicit courtship activity from female axolotls.

Sexual conflict over mating in red-sided garter snakes (Thamnophis sirtalis) as indicated by experimental manipulation of genitalia

Sexual conflict over mating can result in sex-specific morphologies and behaviours that allow each sex to exert control over the outcome of reproduction. Genital traits, in particular, are often directly involved in conflict interactions. Via genital manipulation, we experimentally investigated whether genital traits in red-sided garter snakes influence copulation duration and formation of a copulatory plug. The hemipenes of male red-sided garter snakes have a large basal spine that inserts into the female cloaca during mating. We ablated the spine and found that males were still capable of copulation but copulation duration was much shorter and copulatory plugs were smaller than those produced by intact males. We also anaesthetized the female cloacal region and found that anaesthetized females copulated longer than control females, suggesting that female cloacal and vaginal contractions play a role in controlling copulation duration. Both results, combined with known aspects of the breeding biology of red-sided garter snakes, strongly support the idea that sexual conflict is involved in mating interactions in this species. Our results demonstrate the complex interactions among male and female traits generated by coevolutionary processes in a wild population. Such complexity highlights the importance of simultaneous examination of male and female traits.

Norfloxacin drug induces reproductive toxicity and alters androgen receptor gene expression in testes and cloacal gland of male Japanese quail (Coturnix Japonica)

In an attempt to investigate the reproductive toxicity of norfloxacin in Japanese quail, male quail were given norfloxacin at 20 mg/kg body weight for 14 d. Then reproductive function and androgen receptor (AR) gene expression was examined in treated and control birds. The results of the present study indicate that fertility, cloacal gland area, sperm concentration, and serum testosterone were reduced significantly (p < 0.05) on day 14 in the norfloxacin-treated birds. Upregulation (p < 0.05) of AR mRNA was also seen in the testes on the 14th d of treatment. A trend toward downregulation of AR mRNA was seen in the cloacal gland of norfloxacin-treated birds. Histological observations revealed that norfloxacin induces cellular atrophy in testes and changes in glandular tissue in the cloacal gland. The results of the present study demonstrate that norfloxacin induces testicular toxicity in Japanese quail.

Love is blind: indiscriminate female mating responses to male courtship pheromones in newts (Salamandridae)

Internal fertilization without copulation or prolonged physical contact is a rare reproductive mode among vertebrates. In many newts (Salamandridae), the male deposits a spermatophore on the substrate in the water, which the female subsequently takes up with her cloaca. Because such an insemination requires intense coordination of both sexes, male newts have evolved a courtship display, essentially consisting of sending pheromones under water by tail-fanning towards their potential partner. Behavioral experiments until now mostly focused on an attractant function, i.e. showing that olfactory cues are able to bring both sexes together. However, since males start their display only after an initial contact phase, courtship pheromones are expected to have an alternative function. Here we developed a series of intraspecific and interspecific two-female experiments with alpine newt (Ichthyosaura alpestris) and palmate newt (Lissotriton helveticus) females, comparing behavior in male courtship water and control water. We show that male olfactory cues emitted during tail-fanning are pheromones that can induce all typical features of natural female mating behavior. Interestingly, females exposed to male pheromones of their own species show indiscriminate mating responses to conspecific and heterospecific females, indicating that visual cues are subordinate to olfactory cues during courtship.

Reproductive responses and nitric oxide activity in Japanese quail, Coturnix coturnix japonica, are altered by specific phase relationships of neural (serotonergic and dopaminergic) oscillations and pineal function

The present study investigates the effects of temporal synergism of 5-hydroxytryptophan (5-HTP) and L-dihydroxyphenylalanine (L-DOPA) and pineal function (pinealectomy and melatonin administration) on gonadal response and nitric oxide (NO) activity in Japanese quail. Three-week-old male quails were divided into 9 groups, as follows: (I) control (treated with normal saline); (II) 8-h and (III) 12-h (receiving L-DOPA after the administration of 5-HTP [5mg/100g body weight] at the interval of 8 and 12h, respectively, over a period of 13 days); (IV) SO (sham operated); (V) Px (pinealectomized); (VI) Veh (vehicle treated control); (VII) Mel (melatonin 25 microg/100g body weight for 45 days); (VIII) 12-h+Veh; and (IX) 12-h+Mel (same as in (III) but further treated with the vehicle or melatonin, respectively, for 32 days). Body weight and cloacal gland volume were recorded weekly, whereas spermatogenesis, plasma testosterone concentration, and total nitrite and nitrate concentration in plasma, hypothalamus, and testes were measured at the termination of the study. Results indicate that compared to the controls, 8-h, Mel, and 12-h+Mel treatments suppressed whereas 12-h and Px stimulated the reproductive system. Further, a significant increase in plasma testosterone, total nitrite, and nitrate in the 12-h and Px groups and a decrease in these concentrations in 8-h, Mel and 12-h+Mel quail were observed. It is evident that 5-HTP and L-DOPA given at the interval of 8h, as well as melatonin, are potent inhibitors of gonadal development, and the gonado stimulatory effect of the 12-h temporal relationship of the neurotransmitter precursors is masked by the inhibitory effect of melatonin. It is concluded that modulation of the daily phase relationship of neural oscillations and pineal function alters gonadal function and NO activity. Further, NO exhibits a parallel relationship with gonadal function in Japanese quail; this relationship appears to be mediated through NO activity, suggesting a causal relationship, although the mechanism between the 2 systems remains a topic of discussion.

Embryonic and posthatching treatments with sex steroids demasculinize the motivational aspects of crowing behavior in male Japanese quail

Demasculinizing action of embryonic estrogen on crowing behavior in male Japanese quails was examined. Eggs were treated with either 20 microg of estradiol benzoate (EB) or vehicle on the 10th day of incubation. Chicks hatched from both groups of eggs were injected daily with either testosterone propionate (TP; 10 microg/g b.w.), 5alpha-dihydrotestosterone (DHT, a non-aromatizable androgen; 10 microg/g b.w.), or vehicle from 11 to 50 days after hatching, and during this period their calling behaviors were observed. Irrespective of embryonic treatments, all birds received posthatching treatment with either TP or DHT, but not with vehicle, emitted crows in place of distress calls in a stress (non-sexual) context of being isolated in a recording chamber. The posthatching TP, but not posthatching DHT, induced crowing in a sexual context (crowing in their home-cages) from much earlier age than posthatching vehicle in the birds received control embryonic treatment with vehicle. The same TP treatment, however, completely eliminated the crowing in a sexual context in the birds received EB during their embryonic life. In the birds treated with either posthatching DHT or posthatching vehicle, the crowing in a sexual context was only slightly decreased by embryonic EB treatment. These data suggest that posthatching estrogen, derived from testosterone aromatization, enhances the demasculinizing action of embryonic estrogen, and thus strongly reduces the sexual motivation for crowing behavior. This demasculinizing action, however, would not influence vocal control system which generates acoustic pattern of crowing in the presence of androgens allowing the birds to crow in a non-sexual context.

Rapid action on neuroplasticity precedes behavioral activation by testosterone

Testosterone has been shown to increase the volume of steroid-sensitive brain nuclei in adulthood in several vertebrate species. In male Japanese quail the volume of the male-biased sexually dimorphic medial preoptic nucleus (POM), a key brain area for the control of male sexual behavior, is markedly increased by testosterone. Previous studies assessed this effect after a period of 8-14 days but the exact time course of these effects is unknown. We asked here whether testosterone-dependent POM plasticity could be observed at shorter latencies. Brains from castrated male quail were collected after 1, 2, 7 and 14 days of T treatment (CX+T) and compared to brains of untreated castrates (CX) collected after 1 or 14 days. POM volumes defined either by Nissl staining or by aromatase immunohistochemistry increased in a time-dependent fashion in CX+T subjects and almost doubled after 14 days of treatment with testosterone while no change was observed in CX birds. A significant increase in the average POM volume was detected after only one day of testosterone treatment. The optical density of Nissl and aromatase staining was also increased after one or two days of testosterone treatment. Activation of male copulatory behavior followed these morphological changes with a latency of approximately one day. This rapid neurochemical and neuroanatomical plasticity observed in the quail POM thus seems to limit the activation of male sexual behavior and offers an excellent model to analyze features of steroid-regulated brain structure and function that determine behavior expression.

Dietary phytoestrogens and photoperiodic response in a male songbird, the Dark-eyed Junco (Junco hyemalis)

Many commercial bird diets are made with soy products that contain phytoestrogens (i.e., plant compounds that have weak agonist activity at estrogen receptors), but the effects of these compounds on bird physiology and behavior are largely unknown. The primary phytoestrogens present in soy are the isoflavones genistin and diadzin, which have been shown to affect reproductive measures in many taxa. Two groups of wild-caught male Dark-eyed Juncos (Junco hyemalis) were fed a diet either made with water-washed soy protein (soy(+)) or made with soy protein that had been alcohol-washed to extract isoflavones (soy(-)). Both groups exhibited a photoperiodic response to long days. Plasma luteinizing hormone (LH) concentrations increased within the first week of long day (LD) exposure for both groups, and over the course of the experiment LH was higher in the soy(+) group, although concentrations for both groups were lower than have been reported in free-living juncos. The rate of cloacal protuberance (CP) growth was significantly affected by diet, with the soy(-) birds beginning to increase their CPs about a week faster than soy(+) birds after exposure to LD. There was no group difference in food intake, fat score, body mass, or behavioral measures during the study or in testis weight at the end of the study. Although effects of dietary phytoestrogens detected were subtle (i.e., rate of CP growth), those investigating subtle effects of hormonally active substances (e.g., endocrine disruptors) or environmental cues affecting the reproductive axis in songbirds may want to consider eliminating phytoestrogens from their experimental diets.

Effects of supplemental vitamin E in diet of Japanese quail on male reproduction, fertility and hatchability

1. Two experiments were conducted to examine the effect of feeding higher supplemental vitamin E (VE) concentrations on male reproductive variables, fertility and hatchability of quails. 2. In experiment 1, sixty 5-week-old male quails, reared in individual cages, were fed male breeder diets supplemented with 0, 75, 150, 225 or 300 IU alpha-tocopherol acetate/kg. At 10 weeks, observations on cloacal gland size, foam production, testes weight and blood samples for testosterone estimation were taken. 3. In experiment 2, 50 male and 50 female cage-reared quails (5 weeks old) were fed male breeder and layer rations, respectively, supplemented with 0, 75, 150, 225 or 300 IU/kg. At 13 weeks, 9 different mating pairs (5 pairs/group) were formed. Group 1 contained one control male and one control female in each of 5 pens. In groups 2 to 5, control males were paired with females on supplements of 75, 150, 225 or 300 IU/kg. In groups 6 to 9, control females were paired with males on supplements of 75, 150, 225 and 300 IU/kg. During subsequent adaptation and egg collection periods, each of 10 d, control layer ration was fed to all groups. All the eggs laid during the 10-d egg collection period were incubated artificially to estimate fertility and hatchability. The trial was repeated at 15 weeks. 4. Adult male quails receiving moderate supplemental VE (75 and 150 IU/kg) had a higher cloacal gland index, quantity of foam secretion, testicular weight and plasma testosterone than quails fed on either VE-deficient or more highly supplemented diets (225 and 300 IU alpha-tocopherol acetate/kg). 5. It was concluded that a supplement of 75 IU VE/kg in maize/soybean diet could provide the best reproductive performance of male breeder quails. Cloacal gland index, quantity of foam secretion, testicular weight and plasma testosterone can serve as indirect indicators of testicular activity and fertilising ability in quails. Supplemental VE did not affect the fertility and hatchability of male and female Japanese quails.

Effects of xylazine, medetomidine, detomidine, and diazepam on sedation, heart and respiratory rates, and cloacal temperature in rock partridges (Alectoris graeca)

In this study, heart and respiratory rates, cloacal temperature, and quality of sedation were evaluated before (0 min) and after (10, 20, and 30 min) i.m. administration of xylazine (10 mg/kg; n = 7), medetomidine (75 li; n = 6), detcmidine (0.3 mg/kg; n = 6), or diazepam (6 mg/kg; n = 7) in rock partridges (Alectoris graeca). All partridges recovered from sedation without any disturbance. Xylazine and diazepam administration did not induce significant changes in heart rate, which did decrease significantly after medetomidine and detomidine administration (P < 0.001). Mean respiratory rate was decreased dramatically at 20 and 30 min after xylazine (P < 0.001) and medetomidine (P < 0.005) administration, and at all stages of sedation after detomidine injection (P < 0.001), whereas there was not any significant change after diazepam injection. In all groups, cloacal temperature measured at 10, 20, and 30 min tended to decrease compared with baseline values. Sedative effects of the drugs started within 2.1+/-0.2 min for detomidine, 2.6 +/- 0.4 min for diazepam, 3.1 -+/-.4 min for xylazine, and 4.8+/-0.8 min for medetomidine application. There was an extreme variability in time to recovery for each drug: 205 +/-22.2 min for xylazine, 95 -12.2 min for medetomidine, 260+/-17.6 min for detomidine, and 149 + 8.3 min for diazepam. In conclusion, xylazine, medetomidine, detomidine, and diazepam produced sedation, which could permit some clinical procedures such as handling and radiographic examination of partridges to occur. Of the four drugs, xylazine produced stronger and more efficient sedation compared to the others, which could permit only minor procedures to be performed. However, depending on the drug used, monitoring of heart and respiratory rates and cloacal temperature might be required.

Effect of dietary Vitamin E on the cloacal gland, foam and semen characteristics of male Japanese quail

This experiment was to investigate the effects of increasing the level of dietary Vitamin E (Vit. E) on cloacal gland size, foam production and semen characteristics of male Japanese quail (Coturnix coturnix Japonica). One hundred and eighty male Japanese quail chicks (day old) were randomly distributed to three dietary treatments for a period of 25 weeks. Each treatment comprised of three replicates each containing 20 chicks. The basal diet contained 15 IU Vit. E/kg and the two experimental diets were supplemented with 150 and 300 IU Vit. E/kg (diets T2 and T3, respectively). DL alpha-tocopherol acetate was used as the source of Vit. E. All chicks were provided feed and water ad libitum. Foam characteristics, in terms of frequency of foam discharge (24h), cloacal gland index and foam weight were significantly higher (P<0.05) in T2 group. Body weight, testes weight (left and right) and plasma testosterone concentrations did not differ significantly. Semen characteristics (semen volume, sperm motility, % live sperm, % hatchability and sperm concentrations) did not differ significantly (P>0.05). Percentages of abnormal and dead spermatozoa were significantly (P<0.05) lower and fertility was higher (P<0.05) in the T2 group. From this study, it can be concluded that moderate supplementation of dietary Vit. E may be beneficial for foam production, cloacal gland and improve the semen characteristics in male Japanese quail.

Impairment of testicular function in adult male Japanese quail (Coturnix japonica) after a single administration of 3-methyl-4-nitrophenol in diesel exhaust particles

The effects of 3-methyl-4-nitrophenol (PNMC), a component of diesel exhaust, on reproductive function were investigated in adult male Japanese quail. The quail were treated with a single i.m. dose of PNMC (78, 103 or 135 mg/kg body weight), and trunk blood and testes were collected 1, 2 or 4 weeks later. Various levels of testicular atrophy were observed in all groups treated with PNMC. Sperm formation, cloacal gland area, and plasma LH and testosterone concentrations were also reduced in birds with testicular atrophy. To determine the acute effect of PNMC on gonadotrophin from the pituitary, adult male quail were administrated a single i.m. injection of PNMC (25 mg/kg), and plasma concentrations of LH were measured at 1, 3 and 6 h. This dose significantly lowered plasma levels of LH at all three time points. These results suggest that PNMC acts on the hypothalamus-pituitary axis, by reducing circulating LH within a few hours of administration and subsequently reducing testosterone secretion. In addition, in order to investigate the direct effects of PNMC on the secretion of testosterone from testicular cells in quail testes, cultured interstitial cells containing Leydig cells were exposed to PNMC (10(-6), 10(-5) or 10(-4) M) for 4, 8 or 24 h. These quantities of PNMC significantly reduced the secretion of testosterone in a time- and dose-dependent manner. The present findings also suggest a direct effect of PNMC on the testis to reduce testosterone secretion. This study clearly indicates that PNMC induces reproductive toxicity at both the central and testicular levels, and disrupts testicular function in adult male quail.

Effect of Glycerol Monocaprate (Monocaprin) on Broiler Chickens: An Attempt at Reducing Intestinal Campylobacter Infection

Attempts have been made by several workers to prevent or to reduce colonization of Campylobacter in the intestines of broiler chickens by adding antibacterial agents to their food, but the results have varied. Monocaprin, the 1-monoglyceride of capric acid, has been found to be very active in killing Campylobacter in vitro. It was therefore studied whether Campylobacter infection in chickens would be affected by adding emulsions of monocaprin to their drinking water and feed. It was found that treatment with monocaprin in water and feed did not prevent spread of Campylobacter from artificially infected to noninfected 24-d-old chickens, but Campylobacter counts in cloacal swabs were significantly reduced, particularly during the first 2 d of treatment. There was also a significant reduction in the Campylobacter counts in cloacal swabs of naturally infected 36-d-old broilers that were treated for 3 d prior to slaughter. Addition of monocaprin to drinking water and feed 2 to 3 d before slaughter might therefore be considered as a means of reducing Campylobacter infection in broilers, possibly in conjunction with other antibacterial agents such as short-chain organic acids. Further studies are needed to determine whether this would reduce carcass contamination.

Effects of androgens and estrogens on crowings and distress callings in male Japanese quail, Coturnix japonica

In male Japanese quail, crowing behavior is considered to be strictly androgen-dependent. It was previously shown that in chicks, treatment with either testosterone or 5alpha-dihydrotestosterone (5alpha-DHT; a non-aromatizable androgen) induced crowing with motivation for distress calling in acutely isolated conditions. Many studies, however, have shown that the potencies of testosterone and 5alpha-DHT in activating crowing in castrated males are different. To clarify the effects of androgenic and estrogenic actions on the production of crows and distress calls, we injected quail daily from 11 to 42 days after hatching (Day 11 to 42) with testosterone propionate (TP), 5alpha-DHT, estradiol benzoate (EB) or vehicle and examined their calling behaviors both in a recording chamber (acutely isolated conditions) and in their home-cages (well-acclimated conditions). Both TP- and 5alpha-DHT-treated birds began to crow by Day 13 when isolated in the recording chamber. The TP-treated birds, however, crowed less frequently than 5alpha-DHT-treated ones. This, combined with the observations that distress calling was strongly inhibited in EB-treated birds, suggests that estrogen converted from testosterone may inhibit the motivation for distress calling. On the other hand, after chronic treatment of TP, but not of 5alpha-DHT, birds began to crow intensely in their home-cages earlier than vehicle treated controls, suggesting that estrogen is needed to initiate crowing behavior in sexually active males. Taken together, it is suggested that estrogenic actions affect the motivation underlying vocal behaviors, while the androgenic action is indispensable in generating crowing.

Rapid effects of aromatase inhibition on male reproductive behaviors in Japanese quail

Non-genomic effects of steroid hormones on cell physiology have been reported in the brain. However, relatively little is known about the behavioral significance of these actions. Male sexual behavior is activated by testosterone partly through its conversion to estradiol via the enzyme aromatase in the preoptic area (POA). Brain aromatase activity (AA) changes rapidly which might in turn be important for the rapid regulation of behavior. Here, acute effects of Vorozole, an aromatase inhibitor, injected IP at different doses and times before testing (between 15 and 60 min), were assessed on male sexual behavior in quail. To limit the risk of committing both types of statistical errors (I and II), data of all experiments were entered into a meta-analysis. Vorozole significantly inhibited mount attempts (P < 0.05, size effect [g] = 0.527) and increased the latency to first copulation (P < 0.05, g = 0.251). The treatment had no effect on the other measures of copulatory behavior. Vorozole also inhibited appetitive sexual behavior measured by the social proximity response (P < 0.05, g = 0.534) or rhythmic cloacal sphincter movements (P < 0.001, g = 0.408). Behavioral inhibitions always reached a maximum at 30 min. Another aromatase inhibitor, androstatrienedione, induced a similar rapid inhibition of sphincter movements. Radioenzyme assays demonstrated that within 30 min Vorozole had reached the POA and completely blocked AA measured in homogenates. When added to the extracellular milieu, Vorozole also blocked within 5 min the AA in POA explants maintained in vitro. Together, these data demonstrate that aromatase inhibition rapidly decreases both consummatory and appetitive aspects of male sexual behavior.

The morphogenesis of the exstrophy-epispadias complex: a new concept based on observations made in early embryonic cases of cloacal exstrophy

BACKGROUND

The term exstrophy-epispadias complex (EEC) has been coined for a group of congenital malformations that includes epispadias, bladder exstrophy and cloacal exstrophy. It is usually thought that these malformations develop against a similar embryological background. This background, however, is still obscure. This is mainly due to the lack of availability of abnormal human or non-human embryos showing the crucial developmental steps in the morphogenesis of EEC malformations. In this paper, we present chick embryos that show cloacal exstrophy at early developmental stages. To the best of our knowledge, this is the first documentation of this rare malformation in young embryos.

MATERIALS AND METHODS

Embryos with cloacal exstrophy (n=4) were found among embryos from two experimental series (n=50) that were primarily performed to document the early morphogenesis of facial and cardiovascular malformations. The malformations were induced by the administration of suramin according to established protocols. Suramin can induce a spectrum of malformations including facial clefts, heart defects, and cloacal exstrophy.

RESULTS AND CONCLUSIONS

Besides the presence of an abnormal opening into the cloaca, all embryos were characterised by an abnormal broadening of the caudal trunk at the level of the leg buds, which, in the youngest embryos, was associated with the abnormal presence of large aneurysmatic swellings of the dorsal aortae at this side. We postulate that these aneurysmatic swellings might be the primary defects leading to the development of EEC malformations. These space-occupying anomalies seem to cause abnormal distensions of the developing pelvis and of the infra-umbilical portion of the developing body wall. In consequence, the mid-portion of the developing ventral body wall between the origin of the umbilical cord and the cloacal plate becomes stretched and thinned out. Tension and thinning of the ventral body wall might ultimately lead to its rupture with exposure of the lumen of the embryonic cloaca and allantois. This new concept on the morphogenesis of the EEC is the first not to be inferred from the conditions seen in fetal or postnatal human cases but is based entirely on data from malformed embryos.

The effects of aromatase inhibition on testosterone-dependent conditioned rhythmic cloacal sphincter movements in male Japanese quail

Male Japanese quail produce a foam that, along with semen, is transferred to the quail hen during copulation. This foam has been reported to increase fertility, prolong sperm motility, and enhance sperm competition. Action of the cloacal sphincter muscles in response to visual exposure to a female produces the foam. The rhythmic cloacal sphincter movements (RCSM) responsible for foam production in male quail is elicited by a conditioned stimulus (CS) previously paired with access to a quail hen. These conditioned RCSM are testosterone-dependent. The present experiment was conducted to explore whether, as is the case with most other testosterone-dependent male sexual behaviors in the quail, conditioned RCSM are mediated by the aromatization of testosterone. Castrated, testosterone-treated male quail were presented with paired presentations of an arbitrary focal CS and visual access to a female. Once conditioned RCSM had developed, subjects received twice daily injections of the aromatase inhibitor Vorozole (R083842) during a series of extinction test presentations of the CS. Injections of Vorozole significantly decreased the number of RCSMs elicited by a sexual CS. This decrease was specific to sexual RCSM; cloacal sphincter movements that occurred following defecation were not affected by Vorozole. Conditioned sexual RCSM are therefore mediated by the aromatization of testosterone, most likely due to effects on central aromatase activity related to sexual motivation.

Androgen control of immunocompetence in the male house finch, Carpodacus mexicanus Müller

The immunocompetence handicap (ICH) hypothesis predicts that elevated levels of the gonadal androgen testosterone (T) entail obligatory costs, such as immunosuppression, but evidence supporting this immunosuppressive influence is equivocal. To investigate this question, adult males house finches, Carpodacus mexicanus, were exposed to short days and chronically treated with T-filled (T males; N=10) or empty (C males; N=10) Silastic capsules. Testosterone administration increased plasma T levels and the size of the cloacal protuberance, an androgen-dependent secondary sexual characteristic. To study humoral immunity, finches received injections of sheep red blood cells (SRBC) and we measured circulating concentrations of antibodies to these cells with a hemagglutination test. All males produced antibodies following four SRBC injections at weekly intervals. Antibody titers in T and C males did not differ 5 days after the fourth injection, but were 59% lower in T than C males 2 weeks later. To study cell-mediated immunity, we measured the local inflammatory response to an injection of phytohemaglutinin (PHA). This response in T and C males was similar 1 day after PHA injection, but was 58% less in T than C males 2 days following the injection. Thus, T and C males mounted similar humoral and cell-mediated immune responses, but T treatment compromised maintenance of these responses. The results, demonstrating immunosuppressive effects of elevated T, are consistent with the ICH hypothesis.

Isolation of E. coli from foam and effects of fluoroquinolones on E. coli and foam production in male Japanese quail

Sexually active male Japanese quail (Coturnix coutrnix Japonica) produce a foamy substance from their cloacal gland. It was postulated that bacteria played an important role in production of foam. The primary objective of this study was to isolate and identify bacteria present in the cloacal foam. The secondary objective was to evaluate the effect of fluoroquinolone treatment on bacterial counts and foam production. Healthy adult Japanese quail were maintained in individual cages under uniform husbandry conditions and allocated arbitrarily into three groups (each group consisted of 12 male and 12 female birds). Foam was collected from the cloacal gland of male birds of each group separately into sterile petri dishes and was cultured to isolate and identify bacteria and to determine their sensitivity to various antibiotics. Escherichia coli bacteria, sensitive to various antibacterials (including the fluoroquinolones ciprofloxacin and pefloxacin), were isolated. In the second part of the study, male quails of Group I (control) received I mL vehicle (normal saline 0.9% (w/v) NaCl) daily (via the intraperitoneal route) for 12 days. Male birds from groups II and III were treated intraperitoneally with ciprofloxacin or pefloxacin at the rate of 10 mg and 12 mg per/kg body weight respectively, for 12 days. In antibiotic-treated birds, there was a gradual reduction in foam production during treatment. At the end of treatment, the cloacal gland area was smaller (P < 0.05) in pefloxacin-treated birds compared to the other groups. Furthermore, a trend towards decreasing body weight and fertilizing ability was noted in the same group. A drastic reduction in bacterial counts of foam was recorded only in fluoroquinolone-treated groups during treatment period. After cessation of treatment, all end points were increasing back to pre-treatment levels. In conclusion, E. coli were present in the foam of the cloacal gland of Japanese quail and may have a role in foam production.

Reproductive impairment in Japanese quail (Coturnix japonica) after in ovo exposure to o,p'-DDT

We have previously described various effects in adult Japanese quail consequent on treatment with oestrogenic compounds in ovo. In the present study, the environmental contaminant o,p'-DDT [1-(2-chlorophenyl)-1-(4-chlorophenyl)-2,2,2-trichloroethane] was administered to quail eggs to further evaluate test endpoints for oestrogenic effects related to reproduction in the Japanese quail. Exposure to 2 mg o,p'-DDT/egg (150 micro g/g egg) resulted in impaired sexual behaviour, reduced cloacal gland area and lowered plasma testosterone concentration in males. Females displayed oviductal abnormalities, including retained right oviduct, decreased length of left oviduct, alterations in shell gland morphology and disrupted distribution of carbonic anhydrase in the shell gland. Egg laying was severely impaired. Consequently, a number of endpoints in adult quail may be useful for demonstrating an oestrogen-like mode of action by environmental contaminants during embryonic development.

Effects on health and blood plasma parameters of laying hens by pure nivalenol in the diet

The effects of trichothecene nivalenol (NIV) on the health and production of laying hens were determined in a feeding study. White Leghorn hens, 55 weeks old, were fed diets containing 0, 1, 3 and 5 mg NIV/kg during 50 days. Feed intake was reduced by NIV, but there were no effects on body weight, egg production and egg quality. Traces of unaltered NIV were found in liver and bile. Alkaline phosphatase in the blood plasma increased in the hens fed 0, 1 and 3 mg NIV/kg diet but decreased in the birds fed 5 mg NIV/kg feed. Total protein and glucose were slightly reduced in hens fed 5 mg NIV/kg diet. Pathological examination revealed that 40-75% of hens fed NIV (3 and 5 mg/kg) supplemented diet showed gizzard lesions, haemorrhages in the duodenum and swollen cloaca and oviducts with immature eggs while certain birds in the 1 mg NIV group showed light and fragile livers. NIV and the metabolite de-epoxy-NIV in faeces were found to constitute up to 10% of ingested NIV.

Morphology of the cloaca in the estuarine crocodile, Crocodylus porosus, and its plastic response to salinity

The cloacal complex of Crocodylus porosus is composed of three chambers (proctodaeum, urodaeum, and coprodaeum) separated by tight, muscular sphincters. The proctodaeum is proximal to the cloacal vent and houses the genitalia. The urodaeum is the largest chamber, is capable of storing large quantities of urine, and is lined with an epithelium with the capacity for transepithelial water and ion exchange. The coprodaeum, the most orad cloacal chamber, is a small, only marginally expandable chamber that has an epithelium composed almost entirely of mucus-secreting cells. The coprodaeum and lower intestine are reported to be the site(s) for urine modification in birds and bladderless lizards. A radiographic trace of urine storage in C. porosus kept for 2 months under hyperosmotic conditions showed no signs of retrograde movement of urine into the coprodaeum or rectum. Instead, urine was stored in the urodaeum of C. porosus. Examination of the mucosal surface of the urodaeum by SEM showed a plastic response to environmental salinity, with a possible increase in surface area in animals kept in hyperosmotic water compared with animals from fresh water. We propose the urodaeum as the primary site for postrenal modification of urine in C. porosus.

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.

Synergistic control by androgens and estrogens of aromatase in the quail brain

Castrated quail were injected with testosterone or with the synthetic hormones diethylstilbestrol (DES) or methyltrienolone (R1881) to analyse the steroid specificity in the induction of brain aromatase. R1881 produced a moderate (generally non-significant) increase in the number of aromatase-immunoreactive cells. DES significantly increased the number of positive cells in most brain areas. A clear synergism between DES and R1881 was observed in all brain regions: more immunoreactive cells were found in birds receiving both compounds than in those injected with DES or R1881 alone. DES and R1881 are highly specific ligands for oestrogen and androgen receptors respectively. It appears likely that both androgens and oestrogens directly modulate brain aromatase, presumably at the transcription level.

Current-noise analysis of Na absorption in the embryonic coprodeum: stimulation by aldosterone and thyroxine

The mechanism and regulation of sodium transport in the embryonic coprodeum of chicken were investigated with isolated epithelia in vitro by electrophysiological techniques. Electrogenic sodium transport (INa) was measured in Ussing chambers by the short-circuit current (Isc) technique and identified by the diuretic amiloride or by removal of sodium from the apical medium. Apical sodium channels and the kinetics of amiloride binding were investigated by current-noise analysis. Isc and INa were measured under control conditions and under the influence of in vitro incubation with aldosterone and thyroxine. At 20 days the embryonic coprodeum has an Isc of 12.6 +/- 1.4 microA/cm2 and a transepithelial resistance of 519 +/- 40 omega.cm2. Amiloride blocks 9.0 +/- 1.3 microA/cm2 of the Isc, which represents electrogenic Na+ absorption and can be inhibited by serosal ouabain. Aldosterone does not stimulate Isc or INa, whereas thyroxine increases Isc and INa about threefold. Aldosterone in combination with thyroxine increases Isc and INa further to about five- to sixfold. In both cases the hormonal stimulation can be totally blocked by spironolactone. Current-noise analysis of the apical Na+ entry step reveals amiloride-sensitive Na+ channels with a single-channel current of approximately 2.3 pA and a channel density of 9-16 million/cm2 under stimulated conditions. Half-maximal amiloride block occurs at 0.8-1 microM. The hormones stimulate Na+ absorption by increasing the Na+ channel density and not the single-channel current.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of α-methyl-para-tyrosine on monoamine levels in the japanese quail: Sex differences and testosterone effects

Experiments were performed to obtain more information on the regulation by steroids of catecholaminergic systems in the brain of Japanese quail. Dose-response and time-response experiments were first performed to determine optimal conditions for measuring turnover in the quail brain. The norepinephrine and dopamine turnover were then estimated in microdissected brain nuclei of birds that were either sexually mature or gonadectomized or gonadectomized and treated with testosterone. Two major facts that bear direct relationship with the control of masculine reproductive behavior were demonstrated. On one hand, the dopamine turnover in the medial preoptic nucleus, a sexually dimorphic brain structure which is critically implicated in the control of copulatory behavior was much higher in male than in female quail irrespective of the hormonal condition of the birds. On the other hand, norepinephrine concentrations appeared to be higher in several nuclei of the female brain by comparison with males. These sex differences might represent part of the causal factors that underlie the sex dimorphism in reproductive behavior in quail.

Effect of 12 hr temporal relation of serotonin and dopamine precursor drugs (5-HTP and L-DOPA) on photosexual responses of immature Japanese quail

To study the interaction of photoperiod and circadian neurotransmitter activity, L-DOPA L-dihydroxyphenylalanine, dopamine precursor) was administered daily, 12 hr after 5-HTP (5-hydroxy tryptophan, serotonin precursor) in sexually immature Japanese quail, raised under short photoperiod (LD8:16) since hatching. The 12 hr treatment of 5-HTP and L-DOPA was given under continuous condition of light for 11 days. After treatment the quail were transferred to intermediate day length (LD 13.5:10.5). The cloacal gland size of drug treated group increased significantly in comparison to control. The quail were then transferred to short photoperiod (LD 8:16). The cloacal gland size of both the groups started decreasing gradually but the rate was significantly low in drug treated quail in comparison to control. The results indicate that the endogenous mechanism controlling seasonality may be reset by drugs that influence serotonergic and dopaminergic activity. The 12 hr relation between the two drugs is stimulatory for gonadal growth under intermediate day length and retards the rate of regression when transferred to short days.

The induction by testosterone of aromatase activity in the preoptic area and activation of copulatory behavior

A series of 4 experiments was designed to study the relationships between the activity of the aromatase (AA) in the preoptic area (POA) and the activation by testosterone (T) of copulatory behavior in gonadectomized male and female Japanese quail. The induction of AA by T in the POA is dose- and time-dependent. Levels of AA seen in sexually mature males are restored in castrated birds by a treatment with 20 to 40 mm silastic T capsules which produce physiological levels of steroid in the plasma. The minimal dose of T (10 mm implant) which reliably restores copulatory behavior approximately doubles the AA in the POA. The induction of AA is significantly larger in males than in females. A significant increase in AA is observed within 16 hours after the start of the treatment with T and the induction is maximal after 48 hours. Activation of copulatory behavior follows a similar time course but occurs with a delay of 24-48 hours. These results thus suggest that, in male quail, the activity of the aromatase in the POA is a limiting factor in the activation of copulatory behavior. This idea is confirmed by direct experimentation using an aromatase inhibitor, androstatrienedione (ATD). If T-treated birds receive at the same time silastic implants filled with ATD, the activation of behavior is suppressed for at least one week. This behavioral inhibition is, as expected, accompanied and very probably caused by the inhibition of the aromatase activity in the preoptic area and anterior hypothalamus. No increase of enzyme activity over the level seen in castrates was actually detected during the first 8 days of exposure to T. A moderate increase in AA was seen on day 16 and is probably responsible for the behavioral activation which was observed at the end of the experiment.

Action of activated 27,000 Mr toxin from Bacillus thuringiensis var. israelensis on Malpighian tubules of the insect, Rhodnius prolixus

The action of activated 27,000 Mr toxin from Bacillus thuringiensis var. israelensis (Bti toxin) on Malpighian tubules of Rhodnius prolixus has been investigated. Its binding to the tubules is slowed by low temperature but is not prevented even at 0 degree C. The binding is less effective at pH 10 than at pH7. Pretreatment of the tubules with 0.1 mmol l-1 ouabain or bumetanide or 1 mumol l-1 5-hydroxytryptamine did not affect the toxicity of the toxin. The toxin causes very large changes in the trans-epithelial potential difference; it changes from 40 mV, lumen negative, often to more than 100 mV, lumen positive. This reflects an initial collapse of the potential of the basal cell membrane, followed by a large positive-going potential change at the luminal cell membrane. Just prior to the effects of the toxin on rapid fluid secretion, the basal cell membrane becomes permeable to sucrose molecules. Raffinose at 170 mmol l-1 in the bathing solution does not protect the tubules from Bti toxin action but dextran, Mr5000, at 60 mmol l-1 significantly delayed failure of fluid secretion and, even more, the onset of staining of the tubule cells with Trypan Blue. Exposing tubules to saline that is calcium-free and/or magnesium-free, or has a composition adjusted to be similar to that of the intracellular milieu, does not affect the time course of failure of fluid secretion induced by the toxin. There is no evidence that effective aggregates of Bti toxin molecules are formed in concentrated solutions.(ABSTRACT TRUNCATED AT 250 WORDS)

The initial stages in the action of an insecticidal delta-endotoxin of Bacillus thuringiensis var. israelensis on the epithelial cells of the malpighian tubules of the insect, Rhodnius prolixus

The effects of the 27 X 10(3) Mr insecticidal delta-endotoxin from Bacillus thuringiensis var. israelensis have been studied using, as a model system, isolated insect Malpighian tubules. At all concentrations of the toxin higher than 1 microgram ml-1 (4 X 10(−8) moll-1) applied to the outer surface of the tubules, fluid secretion failed within about 30 min. Except at very high concentrations, where failure always takes at least 30 s, there was an inverse relationship between the concentration of toxin and the time of failure of toxin-treated tubules. During exposure to toxin, the tubules were initially unaffected for a relatively long period and then rapid failure occurred. If the tubules were removed into toxin-free saline just before failure would have occurred, fluid secretion remained normal for at least 2 h, but on return to the origin toxin-containing saline failure was almost immediate. The toxin was found not to bind to the basement membrane. Ultrastructural changes became evident as tubule failure occurred. These initially involved modifications to the basal side of the cells, but later also to the luminal microvilli. Intercellular junctions became disassociated and cytoplasmic vacuolization occurred. The population of intramembranous particles in the basal membranes became reduced with time. Our findings suggest the following hypothesis for the initial stages in the interaction of the toxin with the tubules. Toxin molecules attach to the accessible cell membranes progressively and irreversibly. They do not readily associate by diffusing laterally in the membrane, so that toxic effects develop only when sufficiently large numbers of them attach close together. The molecules may then associate in some way as a complex, perhaps forming a pore in the membrane. Relatively few such pores lead rapidly to cell failure and death.

Effect of the injection solvent on steroid activity

The effects of testosterone, 5 alpha-dihydrotestosterone, and androstenedione on cloacal gland and sternotracheal muscle growth and on luteinizing hormone plasma levels were studied in Japanese quail. The steroids were given to the animals in daily intramuscular injections and were dissolved either in propylene glycol or in ethanol:saline (1:1). The three steroids had significant effects on the responses which were measured, but the magnitude of this effect was clearly related to the type of vehicle in which the steroids were dissolved. Furthermore there was a significant interaction between the effects of solvents and of steroid; for example, testosterone was much less androgenic than 5 alpha-dihydrotestosterone when dissolved in propylene glycol, but both had similar effects when dissolved in ethanol:saline. The effects of the mode of administration of different steroids on a given physiological response should be taken into consideration.

Inhibition of testosterone metabolism in the brain and cloacal gland of the quail by specific inhibitors and antihormones

The effects of antioestrogens, antiandrogens and of various inhibitors of testosterone metabolism on testosterone metabolism in the quail hypothalamus and cloacal gland were studied by an in-vitro radioenzymatic assay. It was found that antioestrogens and antiandrogens generally had little or no effect on aromatase and 5 alpha- and 5 beta-reductases of testosterone, except when used at very high doses. The 5 alpha-reductase inhibitor, 17 beta-N,N-diethylcarbamoyl-4-methyl-4-aza-5 alpha-androstan-3-one, inhibited both 5 alpha- and 5 beta-dihydrotestosterone production without markedly affecting aromatase activity. Surprisingly, the aromatase inhibitor, 1,4,6-androstatriene-3,17-dione, inhibited not only the production of oestradiol but also that of 5 beta-dihydrotestosterone and, to a lesser extent, 5 alpha-dihydrotestosterone. These unexpected properties should be taken into account when interpreting the results of in-vivo experiments using these compounds.

Androgen regulation of secretions in the sebaceous-like uropygial gland of the male Japanese quail

The uropygial gland of the male quail is a sebaceous-like, androgen-dependent structure. The waxes secreted by this gland consist of fatty acids esterified by alkane-2,3-diols. In adult male quail the relative concentrations of all fatty acids were not affected by castration and testosterone treatment; but in contrast, the relative concentration of dodecane diol was found to be correlated with the androgen levels. In castrated quail administration of testosterone induced an increase in the dodecane diol percentage which was blocked by protein-synthesis inhibitors. Furthermore, the effects of testosterone were found to be neutralized by the administration of cyproterone acetate. Consequently it may be stated that the relative concentration of dodecane diol is indeed a very good marker for androgenicity in the uropygial gland of the male quail. This experimental model seems well suited for evaluating the stimulators and inhibitors of the activity of the sebaceous gland.

The postnatal demasculinization of sexual behavior in the Japanese quail (Coturnix coturnix japonica)

Three experiments were performed to analyze the time course of demasculinization in the Japanese quail and to test the activating and organizing effects of estradiol (E2) in adult sexually active birds. In Experiment 1, males and females were castrated at the age of 1 day or 1, 2, 4, and 6 weeks and treated as adults with testosterone (T). The age of castration had no effect on behavior and morphology in males. Plasma gonadotrophins (LH and FSH) were, however, higher in males castrated at or before than in those castrated after 2 weeks of age. This suggests that postnatal testicular secretions have organizing effects on the pituitary activity. Females which were castrated before 1 week of age were less sensitive to the activating effects of T than males, but were not fully demasculinized. The demasculinization of different reproductive characteristics such as male sexual behavior, cloacal gland size, and weight of the syringeal muscles is achieved in females at different times posthatching. In Experiment 2, castration of male and female quail at the ages of 4 days or 4 weeks confirmed that postnatal ovarian secretions contribute to the full behavioral and morphological demasculinization of females. It is easier to elicit mounting in T-treated females when they are tested in their home cage instead of a test arena. This difference was not observed in males. During Experiment 3, it was impossible to demasculinize sexually active adult males or females by treatment with Silastic implants of E2. E2 did not maintain sexual behavior in ovariectomized females showing male sexual behavior when treated with T but maintained the behavior in males.

Relative potencies of testosterone and 5 alpha-dihydrotestosterone on crowing and cloacal gland growth in the Japanese quail (Coturnix coturnix japonica)

It has been suggested that testosterone is less effective at inducing crowing behaviour in young birds than in adults because of the presence of higher levels of steroid 5 beta-reductase in the young brain, which converts testosterone to inactive 5 beta-reduced metabolites. This hypothesis was tested indirectly by comparing the relative potencies of 5 alpha-dihydrotestosterone (5 alpha-DHT), which cannot be converted to 5 beta-metabolites, and testosterone at inducing crowing in young gonadectomized male and female quail. The promotion of cloacal gland growth by these treatments was also assessed since there are no age-related changes in 5 beta-reductase in this organ. Silicone elastomer implants (2 X 5, 5 and 10 mm) containing 5 alpha-DHT were more effective at stimulating crowing than similar implants of testosterone whilst there was little difference in their potency at inducing cloacal gland growth. These results are consistent with the hypothesis that brain steroid 5 beta-reductase regulates the behavioural activity of testosterone in the brain of young birds.

The effects of testosterone and its metabolites on sexual behavior and morphology in male and female Japanese quail

Adult Japanese quail are sexually dimorphic. Even when implanted with testosterone (T), ovariectomized females fail to copulate and their cloacal glands are smaller than those of males. This may be due to a reduced capacity of the females to transform testosterone into active metabolites (estradiol-17 beta and 5 alpha-dihydrotestosterone). Indeed, in the male quail, estradiol-17 beta (E2) activates copulation whereas 5 alpha-dihydrotestosterone (5 alpha-DHT) activates crowing, strutting and the development of the cloacal gland. To test this hypothesis, we studied the effects of in vivo treatments of male and female quail with the different T-metabolites. Forty-one castrated male and female quail were implanted with subcutaneous silastic implants of T, 5 alpha-DHT, E2 and E2 in combination with 5 alpha-DHT. When implanted with these metabolites, females failed to copulate and their cloacal glands remained less developed than those of males. Sexual differences in behavior and morphology thus cannot be entirely explained by sexual dimorphism of the metabolism.

Effect of corticosterone on the hypothalamic-pituitary-gonadal system of male Japanese quail exposed to either short or long photoperiods

Male quail were bred under short photoperiods of 8 h light: 16 h darkness (8L : 16D; SD) for the first 4 weeks of life and were then transferred to either long photoperiods of 16L : 8D (LD) or maintained under the SD regime. Both groups of birds were treated for 2 weeks with a daily dose of either 0·25 or 1·0 mg corticosterone. The conversion of [14C]testosterone in vitro into 5α- and 5β-dihydrotestosterone (5α- and 5β-DHT), 5α- and 5β-androstane-3α,17β-diol, and androstenedione was then measured in the pituitary and cloacal glands of all birds. In the hyperstriatum and posterior hypothalamus only 5β-reduced metabolites and androstenedione were detected.

Transfer to LD and injection of corticosterone affected the metabolism of testosterone only in the pituitary and cloacal glands. In the pituitary gland, exposure to LD increased the production of 5α-reduced metabolites but not of either 5β-reduced metabolites or androstenedione. In both SD and LD birds, injections of corticosterone enhanced the production of 5β-reduced steroids and decreased the production of androstenedione. In LD birds corticosterone also decreased the production of 5α-androstane-3α,17β-diol. Plasma levels of LH and FSH were higher in the LD than in the SD birds. In the SD birds treatment with corticosterone increased the level of LH after 14 days of treatment. Exposure to LD decreased the production of 5β-androstane-3α,17β-diol and androstenedione in the cloacal gland and increased the conversion of testosterone into 5α-DHT Treatment with corticosterone increased the production of androstenedione in the cloacal gland of LD birds but decreased it in that of SD birds. Corticosterone also partially blocked the photoinduced growth of the cloacal gland, but it slightly stimulated the growth of the gland in the SD birds. After 2 weeks of treatment SD (but not LD) corticosterone-treated birds had higher testicular weights than the corresponding controls.

It is suggested that treatment with corticosterone might affect the hypothalamic-pituitary-gonadal axis partly through changes in the metabolism of testosterone.

Dietary ferulic acid, biochanin A, and the inhibition of reproductive behavior in Japanese quail (Coturnix coturnix)

A study was conducted to determine the effects to two dietary compounds, biochanin A and ferulic acid, on the reproductive performance of Japanese quail, Coturnix coturnix. These compounds may be present in the diet of wild birds during dry years or at the end of the growing season during normal years. Four treatment groups, each fed a diet supplemented with biochanin A or ferulic acid, and a control group were tested for morphological and behavioral effects before, during and after treatment. Fertility and hatchability data were collected during treatment only. Ferulic acid was shown to inhibit male copulatory behavior during treatment. Biochanin A inhibited male copulatory behavior during and after treatment. Neither drug affected female copulatory behavior though egg-laying was inhibited by the low dose of biochanin A. Ferulic acid significantly reduced the hatchability of eggs. Biochanin A increased the fertility of males and the hatchability of eggs fertilized by them. A correlation between results of this study and natural conditions of reproduction is discussed. It is concluded that both biochanin A and ferulic acid exert inhibiting influences on the reproductive behavior of Coturnix.

Kinetics of amiloride action in the hen coprodaeum in vitro

The kinetics of amiloride action on the isolated epithelium of the hen coprodaeum are reported. Tissues were taken from birds fed on low salt diets for 9-10 days, conditions which induce a high resting short circuit current due to sodium and sensitive to amiloride. The relation between the inhibition of amiloride sensitive short circuit current and blocker concentration obeyed simple mass laws with an apparent stoichiometry of 1:1 between amiloride and the sodium entry sites. The concentration of amiloride producing its half maximal effect (Ki) was 1.77 +/- 0.20 microM at a sodium concentration of 130 mM. There was a shallow dependence of Ki on sodium concentration, the value of Ki falling to 0.78 +/- 0.1 microM at 1.3 mM Na. The relation of Ki to Na concentration was linear indicating competitive antagonism. The sodium concentration which half saturates the amiloride site (KNa) was 80 mM. This value is very different from the concentration of sodium which half saturates SCC (Kscc = 5-7 mM) suggesting there are at least two sites at which sodium can modify the transporting characteristics. These data are compared to those for other epithelia where Kscc and KNa are rather similar. The benzyl derivative of amiloride (benzamil) was found to be 11.6 times more potent than amiloride on this tissue. The potency ration is similar to that for other sodium transporting epithelia suggesting that the structure of the ion translocation mechanism is partly conserved between species although the Ki for amiloride may vary by an order of magnitude.

5-hydroxytryptamine-stimulated mitochondrial movement and microvillar growth in the lower malpighian tubule of the insect, Rhodnius prolixus

Rapid initiation of ion transport occurs in the lower Malpighian tubule of the insect Rhodnius prolixus following feeding in vivo or stimulation with 5-hydroxytryptamine (5-HT) in vitro. Using the electron microscope, we have conducted a morphometric analysis of cells in the lowest one-third of the lower tubule, demonstrating that 5-HT also induces mitochondrial movement and microvillar growth simultaneously with, but independent of, the onset of ion transport. Mitochondria move from a position below the cell cortex to one inside the microvilli within 10 min of stimulation with 5-HT, resulting in an 8- to 10-fold increase in the volume of mitochondria within the microvilli. Previous findings indicated that mitochondrial movement is dependent on actin-containing microfilaments, but not microtubules. As the mitochondria enter the microvillus, the core microfilaments are reorganized into a sheath of microfilaments, which extends closely parallel to the outer mitochondrial membrane down into the cell interior. This sheath of microfilaments is also observed around mitochondria in the axopods. We suggest that the core microfilaments are responsible for mitochondrial movement into the microvilli and axopods. Stimulation with 5-HT induces a shift in mitochondrial configuration from orthodox to condensed, indicating a possible increase in oxidative phosphorylation. Following stimulation, the microvilli grow about 3 X in volume and 2.5 X in surface area. These increases are more than can be accounted for by mitochondrial invasion and must involve the addition of new membrane and microfilament polymerization. The observed changes - microvillar growth, insertion of additional membrane, activation and movement of mitochondria adjacent to the ion transport membrane - are described in the light of their significance in ion transport. A simple model is proposed which unifies the observed ultrastructural changes and known ion movements in the lower tubule.

Cloacal gland of the Japanese quail: androgen dependence and metabolism of testosterone

A cloacal gland complex whose growth and development is androgen-dependent exists in the Japanese quail. In-vitro incubation studies of the cloacal gland using 4-14C-labelled testosterone as substrate allowed the positive identification of five metabolites: androstenedione, 5 beta-dihydrotestosterone (5 beta-DHT), 5 beta-androstane-3 alpha, 17 beta-diol, 5 alpha-DHT and 5 alpha -androstane-3 alpha, 17 beta-diol. More polar metabolites, not yet chemically identified, were detected in trace amounts. Androstenedione appeared to be the main testosterone metabolite in immature birds while in mature birds on long daylengths testosterone was preferentially metabolized to 5 alpha-DHT. This change may have been in response to the higher levels of plasma steroids found in mature birds. When various testosterone metabolites, contained in silicone elastomer capsules, were implanted s.c. into castrated birds maintained on a photostimulatory light regime, 5 alpha-DHT, 5 alpha-androstane-3,17-dione, androstenedione and 5 alpha-androstan-3 alpha-ol-17-one were shown to be equipotent with testosterone in stimulating the development of the cloacal gland. 5 alpha-Androstane-3 alpha, 17 beta-diol and 5 alpha-androstan-3 beta-ol-17-one stimulated some growth while 5 beta-DHT, 5 alpha-androstane-3 beta, 17 beta-diol, 5 alpha-androstane-3 alpha, 17 beta-diol, 5 beta-androstane-3,17-dione, androst-5-en-3 beta-ol-17-one and androst-5-ene-3 beta, 17 beta-diol were completely ineffective.

Effects of catecholamines on thermoregulation in pigeons

1 In unanaesthetized pigeons, kept at room temperature (20-23 degrees C) the effects on cloacal temperature were examined of catecholamines, phenoxybenzamine and propranolol, injected into the cerebral ventricles.2 Noradrenaline, adrenaline, dopamine and isoprenaline caused a fall in cloacal temperature.3 Phenoxybenzamine produced a long-lasting small rise in cloacal temperature. This rise is attributed to removal of the hypothermic effect of noradrenaline released continuously from adrenergic neurones ending in the anterior hypothalamus. Propranolol produced a slight fall in cloacal temperature.4 The hypothermic effects of noradrenaline, adrenaline and dopamine were prevented by phenoxybenzamine but not by propranolol. They are therefore attributed to activation of alpha-adrenoceptors.5 The hypothermic effect of isoprenaline was not prevented by either phenoxybenzamine or propranolol. The effect can therefore not be attributed to activation of either alpha or beta-adrenoceptors. Propranolol actually accentuated the isoprenaline-induced hypothermia.