The metabolism of progesterone by animal tissues in vitro. Sex and species differences in conjugate formation during the metabolism of [4-14C]progesterone by liver homogenates

1. Sex and species differences during the metabolism of [4-¹⁴C]progesterone by liver homogenates from rat, rabbit, guinea pig and hamster have been investigated. 2. Liver homogenate from male rat formed `water-soluble' metabolites faster and in significantly larger amounts than did liver homogenate from female rat. About 65–70% of the added progesterone was conjugated as glucuronide by liver homogenate from male rat and about 45–50% by that from female rat. Liver homogenate from male rat also formed glucuronides faster than did liver homogenate from female rat. Sulphate formation was low (8–16%) in liver homogenates from both male and female rats. 3. Hamster-liver homogenate did not show any sex difference in the rate of formation of `water-soluble' metabolites, but a sex difference was observed in the amount of free steroids recovered at low tissue:steroid ratios. Liver homogenate from female hamster formed glucuronides faster and in significantly larger amounts than did liver homogenate from male hamster, the reverse of what was found in rat liver. 4. Liver homogenates from male and female rabbits and guinea pigs formed `water-soluble' metabolites that were almost entirely glucuronides. 5. Neither rabbit liver nor guinea-pig liver showed any significant sex difference in the rate or amount of formation of total `water-soluble' metabolites or glucuronides, but guinea-pig liver was considerably less active than rabbit liver. 6. Glucuronides were quantitatively the major type of conjugate formed by the liver homogenates from both sexes of all species except the male hamster.     

Prostaglandin induction of spawning behavior in Cichlasoma bimaculatum (Pisces cichlidae)

Prostaglandin (PG) stimulates female spawning behavior in goldfish and in some other teleosts in which female reproductive behaviors consist of postovulatory oviposition acts. This study examined the effects of PG on female sexual behavior in a teleost fish, Cichlasoma bimaculatum, in which female reproductive behaviors involve both preovulatory courtship and substrate cleaning behaviors, and post-ovulatory oviposition behavior. In females of established pairs, PGF2 alpha injection (5 micrograms, im) at any stage of the spawning cycle, or in the parental phase, rapidly induced substrate cleaning which soon merged into oviposition behavior (without egg release). These results support a role for PG in oviposition behavior of Cichlasoma. However, indomethacin (1 mg, ip), a PG synthesis inhibitor, did not block oviposition in ovulated females which had begun to spawn. Indomethacin may not have lowered PG levels sufficiently. Alternatively, as shown by J.J. Polder (1971, Neth. J. Zool. 21, 265), oviposition behavior may be induced or maintained by other factors associated with the spawning situation.     

Hormonal regulation of sex pheromone biosynthesis in the turnip moth,Agrotis segetum

Pheromone production in the female turnip moth, Agrotis segetum, is under the control of a brain factor. This factor was demonstrated to be a proteinaceous substance termed pheromone biosynthesis activating neuropeptide-like substance (PBAN-like substance). The sex pheromone of Swedish A. segetum includes (Z)-5-decenyl acetate, (Z)-7-dodecenyl acetate, and (Z)-9-tetradecenyl acetate as major components. Decapitation of a female decreased pheromone production significantly. Pheromone production was restored by injection of homogenates of either male or female brain-suboesophageal ganglion or the corpora cardiaca alone. Pheromonotropic activity was also found in homogenates of the female thoracic ganglion and abdominal ganglion that were obtained during scotophase. Injection of female brain and thoracic ganglion homogenates made from insects during the scotophase induced two and four times as much Z7-12:OAc, respectively, as injection with similar homogenates from photophase. As little as one-eighth female equivalent (FE) brain homogenate was sufficient to increase the amount of Z7-12:OAc. The effect of brain homogenate on pheromone titer reached its maximum after 30 min. The activity of the PBAN-like substance present in female brain extracts was not correlated to the age of the donor. Injection of hemolymph collected during either photophase or scotophase into decapitated females did not increase the pheromone titer. The target site of the PBAN-like substance was not the pheromone gland, and the ventral nerve cord was not involved in the transportation of the PBAN-like substance, which implies a mode of action different from what has been reported in other moths. Brain homogenates obtained during photophase from females of African A. segetum, Spodoptera littoralis, or Ostrinia nubilalis as well as synthetic Bombyx-PBAN also induced pheromone production in decapitated Swedish female A. segetum. © 1995 Wiley-Liss, Inc.     

Control of Female Reproduction in Drosophila: Genetic Dissection Using Gynandromorphs

The sexual behavior of Drosophila melanogaster gynandromorphs was studied to analyze the relationship between different steps in the female reproductive pathway. It was assumed that, in some gynandromorphs, certain female functions are missing because the corresponding control sites (foci) are either composed of male tissue or did not develop. A given gynandromorph can show elements of both male and female reproductive pathways. None of the steps of the female reproductive pathway appeared to be dependent on any other, in contrast to male behavior where, for example, following of females is a prerequisite for attempted copulation. By correlating each of the behaviors with the genotype of the cuticle, we confirmed previous findings that the focus for the female sex appeal is located in the abdomen, but receptivity to copulation is controlled by a site in the head. Many of the gynandromorphs did not lay eggs, presumably because either the focus controlling egg transfer from the ovaries to the uterus or the one controlling egg deposition was composed of male tissue. Many of the nonovipositing gynandromorphs laid eggs while dying or could be induced to deposit eggs after implantation of hormone-producing glands or topical application of a juvenile hormone analog. Some of the noninseminated gynandromorphs laid eggs at the rate characteristic for inseminated females, suggesting that an oviposition focus (mapping in the head region) suppresses oviposition in virgin females, but not in gynandromorphs whose focus is composed of male tissue. Some of the inseminated gynandromorphs oviposited eggs at a low rate, possibly because the focus responsible for detection of insemination could not function properly. Some of the inseminated gynandromorphs laid unfertilized eggs, revealing the importance of the focus controlling sperm release from the seminal receptacle. Foci controlling egg transfer, egg deposition and sperm release are located in the thorax, according to mosaic fate mapping results and studies on the reproductive behavior of decapitated females. The location of egg deposition in the culture vial seems to be controlled by a brain site. Sexual behavior in Drosophila does not depend on the presence (or absence) of the ovary or germ line.     

Influence of odours of male organ homogenates on maturation of young female meadow voles,Microtus pennsylvanicus

Female meadow vole weanlings exposed to odours from homogenates of bladder and testis taken from sexually mature males showed more rapid maturation (earlier vaginal perforation, heavier uteri, adrenal glands, and ovaries with more and larger Graafian follicles, and cornified smears lacking mucus) than controls exposed to distilled water. Females exposed to kidney homogenates showed similar responses except that their time of vaginal perforation and adrenal weight did not differ from controls, and some had mucous smears. Seminal vesicle, preputial, and prostate homogenates produced only occasional effects on these indicators of reproductive maturation. The pheromone responsible for these effects, known to be present in urine, is deduced to enter the urine stream at the kidney rather than at the level of the sexual accessories.     

Yolk protein immunoassays (YP-ELISA) to assess diet and reproductive quality of mass-reared Orius insidiosus (Heteroptera: Anthocoridae)

A yolk protein enzyme-linked immunosorbent assay (YP-ELISA) was developed for the predator Orius insidiosus (Say). The YP-ELISA is intended to assess reproductive response to dietary and other rearing conditions, and to assist in quality control and diet development for mass rearing. Hybridomas and monoclonal antibodies were produced against homogenates of eggs dissected from females. Hybridomas were selected for secretion of IgG that reacted with extracts of both females and their eggs, and that did not react with male extracts. Each cloned hybridoma produced a monoclonal antibody that specifically reacted on western blots against one of the two major yolk polypeptides, apoVn-I (180,000 molecular weight) or apoVn-II (40,000). Yolk protein ELISAs were developed with these antibodies to assess yolk protein content of female O. insidiosus as a measure of reproductive fitness and as a potential predictor of fecundity. Protocols for an indirect antigen ELISA and double antibody sandwich ELISA were developed to assess yolk protein contents of eggs and total contents in whole body homogenates. ELISA standards consisted of homogenates of eggs collected 0-24 h following oviposition. As determined with the sandwich ELISA, yolk protein contents of eggs declined with age before hatch, with a half-life of 32-34 h. Results were similar whether the detecting antibody-enzyme conjugate was anti-apoVn-I or anti-apoVn-II. Optimal conditions and sampling parameters were developed for the sandwich ELISA, which demonstrated minimal nonspecific interference in whole-insect extracts. In an initial application of the YP-ELISA, oviposition rates over a 10-d period were compared with yolk protein contents at the end of that period, dependent on diets of differing nutritional composition and quality. High and low yolk protein contents correlated with oviposition rates on respective diets, though oviposition showed more graded response to diets than did yolk protein. Improvements in sampling methods are discussed.     

Role of hydroxyl radical scavengers dimethyl sulfoxide,alcohols and methional in the inhibition of prostaglandin biosynthesis

Prostaglandin (PG) F_2α provoked a contraction of longitudinal tissue strips from the uterine, vaginal and isthmus regions of the chicken oviduct; no response was induced in longitudinal tissue strips from the magnum and infundibulum.PGE₂ induced a contraction of circular and longitudinal uterine strips and of circular strips from the isthmus and infundibulum. With both circular and longitudinal vaginal strips a relaxation was obtained. A dose-dependent response was observed with circular magnum strips: contraction with low doses and relaxation at higher doses. No response was obtained with longitudinal tissue strips from the isthmus, magnum and infundibulum.The possible influence of both prostaglandins in the mechanism of ovum transport and oviposition in the domestic hen is discussed.     

Influence of age at mating on the reproductive performance of Parthenium beetle,Zygogramma bicolorata (Coleoptera: Chrysomelidae)

Abstract Age-specific mating incidence, sexual maturation and effect of age at mating on reproductive performance of the Parthenium beetle, Zygogramma bicolorata Pallister, was studied. Based on 50% mating incidence the calculated age of sexual maturation of males and females was 10.5 and 11.1 days, respectively, which was not statistically significant. However, on the basis of age at first mating, that is, sexual maturity, females matured 2 days earlier than males. Fecundity, pre-oviposition, oviposition and post-oviposition period and female longevity appear to be influenced by female age at mating with reproductive performance peaking at 30 days. On the other hand, egg viability was influenced by male age and was highest when males mated at the age of 40 days. To summarise, egg production and timing of egg deposition was female age-dependent, whereas egg fertility was male age-dependent. It was also observed that females mated at a later age and laid a higher number of eggs immediately after mating than did earlier mated females. This was ostensibly in a bid to increase fitness by maximizing reproductive output in the reduced life span available. This is the first investigation on the effect of age of females at mating on reproduction in this beetle.     

An indirect mechanism by which a protein from the male gonad hastens salivary gland degeneration in the female ixodid tick, Amblyomma hebraeum.

In the adult female tick, Amblyomma hebraeum Koch (Acari: Ixodidae), salivary gland degeneration is triggered by an ecdysteroid, provided the female is above a critical weight (approximately 300-400 mg). In mated females, salivary gland degeneration is virtually complete within 4 days of detachment from the host. In virgin females, salivary gland degeneration is delayed by 4 days. This delay can be reversed by the injection of a male reproductive tract homogenate directly into the hemocoel. In this study, we consider a possible mechanism of action for this "male factor." Once mated, male factor likely gains access to its target tissue(s) as a humoral factor. Male factor, however, appears not to act by sensitizing the salivary glands to the action of ecdysteroids. Instead, it appears to act by accelerating the appearance of ecdysteroids in the hemolymph.     

Presence of eupyrene spermatozoa in vestibulum accelerates oviposition in the silkworm moth,Bombyx mori

In the silkmoth, Bombyx mori, mating accelerates egg laying. Sterilized males did not induce females to oviposit, whereas artificial insemination was enough to accelerate oviposition. These findings showed that mechanical stimulation of the outer reproductive organs and the bursa copulatrix (BC) had no effect on oviposition. Factors included in seminal fluids also did not stimulate oviposition because neither implantation of female internal reproductive organs nor injection of the spermatophore extract into virgin females activated oviposition. Preventing sperm precedence by experimental removal of the BC or spermatheca inhibited activation of egg laying. More precise surgeries on the spermatheca showed that the main factor for eliciting oviposition was the presence of matured and fertile eupyrene spermatozoa in the vestibulum. Sperm were not effective unless they reached the vestibulum. Nerve transection and electrophysiological studies revealed that nerve 4 of the terminal abdominal ganglion was the pathway by which the mating signal was transmitted toward the higher central nervous system.     

Female reproductive behaviour,ovarian hormones and vaginal cytology of the induced ovulator, <Emphasis Type="Italic">Ctenomys talarum</Emphasis>

In the present study, we evaluated whether reproductive condition affects female reproductive behaviour in the induced ovulator Ctenomys talarum. We also explored the effect of the interaction with a male on the reproductive condition of females. To evaluate this, we arranged mating trials and evaluated female reproductive behaviour. Reproductive status of females was evaluated using a combined approach of vaginal smears, urinary progesterone and oestradiol, and ovarian histology. Behaviours denoting attraction (‘male sniff’ and ‘mount attempts’) and mutual courtship behaviours (‘spin’ and copula) were correlated with vaginal cytology before and oestradiol and progesterone levels in urine 12 h after male–female encounter. After 24 h of the interaction, oestradiol levels and vaginal epithelization increased while progesterone levels decreased in soliciting females. C. talarum females’ reproductive behaviour was related to its physiological reproductive state and vaginal cytology. The kind of male interaction, whether couples copulated or remained indifferent affected the later status of females. Females are induced ovulators by mating but male presence and interaction also affected other components of their reproductive physiology such as ovarian hormones and vaginal cytology.     

Significance of constraints on genital coevolution: Why do female Drosophila appear to cooperate with males by accepting harmful matings?

The mechanisms driving the coevolution of male and female genital morphologies are still debated. Female genitalia in Drosophila species bear membranous “pouches” or hardened “shields,” which the male genital armature contact during copulation. Although shield‐like structures likely serve to mitigate the effects of harmful mating, some authors have suggested that soft pouches, which do not prevent male genitalia from inflicting wounds, represent a congruent sensory organ. To elucidate the evolutionary forces responsible for the development of such organs, I examined the effects of artificial damage to various genital parts of female Drosophila erecta on reproductive success. Despite a high survival rate among females, damage to the ovipositor plate resulted in frequent failure of insemination and in the embedment of eggs into the substrate. Damage to the vaginal shield resulted in increased mortality and frequent failure of egg embedment, with an egg blocking the vagina under the damaged shield in some females. Wounding of the pouch had less of an effect on both mating and oviposition success, suggesting that the structure “lures” the male trauma‐causing organs to areas where the resultant wounds do not interfere with insemination or oviposition. These data show that the dual functions of female genitalia (mating and oviposition) mediate genital coevolution.     

水稻二化螟的交配行为

在室内条件下,对水稻二化螟Chilo suppressalis的交配行为及能力进行了研究.结果表明：大多数二化螟雌蛾一生只交配一次,平均0.92次;而雄蛾具有多次交配能力,最多达4次,平均2.72次.二化螟雌蛾的日龄影响其交配率、交配起始时间和持续时间,随二化螟雌蛾日龄的增加,其交配率逐渐下降,交配起始时间逐渐提前,而交配持续时间逐渐上升.相反,二化螟雄蛾日龄对其交配率、交配起始时间和持续时间没有明显影响.交配日龄对二化螟雌蛾的生殖力也存在显著影响,随着二化螟雌蛾交配日龄的增加,雌蛾产卵量下降,卵孵化率降低,产卵期缩短,它们都与雌蛾交配日龄存在显著的负相关;而雌蛾产卵前期和雌蛾寿命随雌蛾交配日龄的增加而延长,与雌蛾交配日龄存在显著的正相关.但二化螟雄蛾交配日龄对雌蛾的生殖力没有明显影响,二化螟雄蛾一生都具有较强的交配繁殖能力.同时,不同交配史的雄蛾与雌蛾交配,对雌蛾的生殖力也没有显著影响.表明二化螟的交配活动是由雌蛾主导控制的.最后,对这些结果在二化螟性信息素防治中应用的可行性进行了探讨.在应用性信息素控制二化螟的实践中,可以在两方面取得实效,一是性信息素可以阻碍雌雄之间正常交配,降低交配率;二是可以推迟二化螟雌虫的交配,使其产卵量和卵孵化率降低.     

Sex- and species-related differences in the biotransformation of isosorbide dinitrate by various tissues of the rabbit and rat

The biotransformation of isosorbide dinitrate (ISDN) by various tissues of the rabbit and rat was examined. Incubation of 2 X 10(-7) M ISDN at 37 degrees C with tissue homogenates of liver, lung, kidney, intestine, skeletal muscle, aorta, and erythrocytes from the rabbit and rat resulted in a significant disappearance of ISDN after a 30-min incubation (also, 5-min incubation for liver). The disappearance of ISDN in each tissue homogenate was accompanied by an equimolar production of the mononitrate metabolites, isosorbide-2-mononitrate (2-ISMN) and isosorbide-5-mononitrate (5-ISMN), with the exception of liver homogenates where the loss of ISDN could not be accounted for by mononitrate formation. The relative rate of ISDN disappearance in various tissue homogenates was for the male rabbit, liver greater than lung approximately intestine greater than kidney greater than erythrocytes approximately skeletal muscle approximately aorta; for the female rabbit, liver greater than kidney approximately lung approximately intestine greater than erythrocytes approximately skeletal muscle approximately aorta; and for the male rat, liver greater than intestine greater than erythrocytes greater than skeletal muscle greater than lung approximately kidney. A sex difference in the percent disappearance of ISDN was observed in homogenates of lung and intestine from male and female rabbits. In addition, a sex difference in the ratio of metabolite (2-ISMN/5-ISMN) formed by denitration of ISDN was seen in homogenates of lung, skeletal muscle, and erythrocyte lysate.(ABSTRACT TRUNCATED AT 250 WORDS)     

橘大实蝇的产卵行为观察

2005年6月,在湖北省清江河谷地区早熟蜜柑园内观察了橘大实蝇Bactrocera(Tetradacus)minax(Enderlein)的产卵行为。整个产卵过程可分为定位、准备、穿刺、排卵和结束5个阶段。产卵1次所需的时间和排卵的数量与天气状况有关,一般需时14~46min。产卵深度因柑橘的品种和处在产卵期的果实直径大小而不同,在脐橙、柚、早熟蜜柑上的平均产卵深度分别为7.2,13.3和8.1mm。每雌的怀卵量平均71粒。雌成虫在产卵过程中有多头雄成虫在其周围活动或者是等待与其交尾,产卵和交尾在同一时段内多次交替进行。     

Activation of reproduction in nulliparous and primiparous voles is blocked by vomeronasal organ removal.

Chemical cues from male voles activate reproduction in female prairie voles (Microtus ochrogaster). Twelve hours of contact with a male, followed by exposure to his soiled bedding for 2 days, is sufficient to initiate follicular maturation and induce uterine hypertrophy. Our recent work indicates that the chemosensory vomeronasal organ (VNO) can mediate this response. Here, we examined whether other sensory systems can acquire the ability to activate female reproduction as a result of learning or experience. To explore this issue, the VNO was removed (VNX) from nulliparous and primiparous females who were then exposed to cues from males. In Experiment 1, we found that nulliparous VNX females had lower uterine and ovarian weights than did sham-operated females. In Experiment 2, we determined that sexual experience did not ameliorate the reproductive deficits normally induced by VNX. The present results contrast with those of previous studies suggesting that males of some rodent species, when allowed reproductive experience prior to VNX, can utilize other sensory systems to mediate subsequent reproductive responses. We conclude that the role of the VNO in transducing chemosensory information is crucial for coordinating the reproductive efforts of male and female prairie voles.     

Prostaglandin and prostaglandin synthetase in the cricket, Acheta domesticus

Prostaglandin (PG) synthetase was present in the testes, seminal vesicles, and spermatophores of the male house cricket, Acheta domesticus. The enzyme was not detected in bursa copulatrix, spermatheca, spermathecal canal, and oviducts from virgin females, while substantial activity was measured in the same tissue from mated females. The female appears to receive the enzyme from the spermatophore. A PGE₂-like material was detected by radioimmunoassay in A. domesticus testes and to a lesser extent in the remainder of the male reproductive tract. PG went undetected in virgin female reproductive tissues, while the same tissues from mated females contained an average of 589 pg of PGE₂-like material per female. In in vivo studies, injected PGE₁, PGE₂, and to a smaller degree PGF_2α stimulated oviposition by virgin females. Moreover, N-acetyl-p-aminophenol, a PG synthetase inhibitor, suppressed oviposition in mated females. Post-copulatory PG biosynthesis in the female reproductive tract might be partially responsible for triggering oviposition in A. domesticus. Since PG synthetase appears to be acquired from the male, it could be considered a primer pheromone.     

The effects of exposure to seaweed on willingness to mate, oviposition, and longevity in seaweed flies

Abstract  1. Large male seaweed flies (Diptera: Coelopidae) are more likely to mate than smaller males. This is due to sexual conflict over mating, by which females physically resist male attempts to copulate. In some species, large males are simply more efficient at overpowering female resistance.
2. Female reluctance to mate is likely to have evolved due to the costs of mating to females. In many dipterans, males manipulate female behaviour through seminal proteins that have evolved through sperm competition. This behavioural manipulation can be costly to females, for example forcing females to oviposit in sub-optimal conditions and increasing their mortality.
3. Previous work has failed to identify any ubiquitous costs of mating to female coelopids. The work reported here was designed to investigate the effects of exposure to oviposition sites ( Fucus algae) on the reproductive behaviour of four species of coelopid. Algae deposition in nature is stochastic and females mate with multiple males in and around oviposition sites. Spermatogenesis is restricted to the pupal stage and there is last-male sperm precedence. It was predicted that males would avoid wasting sperm and would be more willing to mate, and to remain paired with females for longer, when exposed to oviposition material compared with control males. Females were predicted to incur longevity costs of mating if mating increased their rate of oviposition, especially in the presence of algae.
4. The behaviour of males of all four species concurred with the predictions; however mating did not affect female receptivity, oviposition behaviour, or longevity. Exposure to algae induced oviposition and increased female mortality in all species independently of mating and egg production. The evolutionary ecology of potential costs of mating to female coelopids are discussed in the light of these findings.     

Clomiphene citrate alters vaginal surface morphology in cycling rats.

Cycling virgin female rats were treated with clomiphene citrate (CC) during dioestrus of the reproductive cycle. Animals were sacrificed 2 days after the initial injection and their vaginal tissue was examined by scanning electron microscopy. Animals treated with one dose of CC had an epithelium consistent with a prolonged dioestrus. Treatment with CC for 2 days induced changes in the epithelium that had no resemblance to any normal hormonally controlled event in the vagina. It was found that CC had effects consistent with progesterone alone as well as effects unique to this superovulatory drug.     

Paternal alleles enhance female reproductive success in tropical pythons

The conventional view that female reproductive success is unlikely to benefit from multiple mating has come under strong challenge in recent years. In the present study, we demonstrate that the time wild-caught reproductive female water pythons (Liasis fuscus) spent in the laboratory prior to oviposition affected both hatching success and the number of male microsatellite alleles detected in the broods. A negative correlation between time in captivity and number of male alleles observed in the broods suggests that reduced hatching success was most likely not caused by environmental factors such as non-optimal temperatures, but rather by restricted mating opportunities. Maternal nutritional status and mean hatchling mass did not affect brood viability. However, our results revealed a positive correlation between number of male microsatellite alleles observed in the broods and hatching success, suggesting that increased paternal genetic variability enhanced female reproductive success. As microsatellite loci are unlikely to be direct targets of selection, we suggest that variability at these loci may cosegregate with other polymorphic genes directly linked to fitness.