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The number of spermatozoa into the Fallopian tubes and levels of in vivo fertilization were measured following different treatment. The results show that copulation by the artificially inseminated animal has a strong influence on the transport of the rabbit spermatozoa and "in vitro" fertilization. This constitutes some more evidence about the physiological role played by the utero-tubal junction.
Pregnant female mice with an impregnation time of 4 hours were achieved by utilizing the Whitten effect and a simple caging system. The cage consisted of a mobile wire-lattice which divided a plastic cage into two compartments to separate the females from the male but still allowed some contact. A synchronization time of 72 hours succeeded in an average copulation rate of 28.1 +/- 5.39% when the procedure was conducted in the forenoon.
This field study of feral stallions in Montana and Idaho examines and correlates the seasonal pattern of plasma androgens and specific sociosexual behaviour and reports the effect of a long-acting androgenic steroid on this behaviour and on fertility. Plasma testosterone was measured by competitive protein binding assay in samples obtained by jugular venepuncture from captured animals. In samples taken from 34 sexually mature stallions in 6 different months during the year, a definite seasonal pattern in testosterone was present, with a peak in May (3.04 +/- 0.63 ng/ml) and a nadir in December (1.55 +/- 0.34 ng/ml). Values were less than 2.0 ng/ml in non-breeding months and greater than 2.4 ng/ml in breeding months. Behavioural endpoints measured were (1) stallion scent marking in response to elimination by mares (elimination marking), (2) mounting and (3) copulation. The frequencies of each of these endpoints followed closely the seasonal pattern seen for plasma androgens. In the fertility study microcapsulated testosterone propionate (microTP) was administered i.m. to 10 harem stud stallions 3 months before the 1980 breeding season. In these stallions and in 10 control harem studs, the above behavioural endpoints were examined in the 1980 and 1981 breeding seasons, and foal counts were made in 1981. There were no direct inhibitory or stimulatory effects of microTP treatment on any of the behavioural endpoints in either year. In 1981 foals were produced in 87.5% of the control bands and 28.4% of the microTP-treated bands. These results indicate that microencapsulated testosterone propionate can provide effective fertility control in feral horses without causing significant alterations in sociosexual behaviour.
Satietin a recently discovered potent endogenous anorectic agent was claimed to be a highly selective anorectic substance, devoid of any effect on other behavioral system. In the copulator male rats, in contrast to amphetamine, fenfluramine and fluoxetine it failed to influence the mating activity. This finding further supports the view that satietin has highly selective effect on feeding behavior.
The kinetics of functional modifications during in vivo or in vitro incubation was studied in spermatozoa from Albino Swiss mice, obtained from cauda epididymis (E) or from uterus (U) or oviduct (O) post copulation (p.c.). Results clearly suggest that functional activity as reflected by measurements of motility, hypoosmotic swelling test and acrosome reaction differs according to the segments of the reproductive tract from which they were collected. The comparison of results obtained after equivalent periods of in vitro or in vivo incubation, shows that the time course of changes in sperm motility and percentage of swollen sperm is similar in both conditions. Since the percentage of acrosome-reacted gametes was higher in O, at all times scored, oviductal environment appeared to be capable of inducing this phenomenon. Our experimental conditions seemed to be adequate for completion of spermatozoa maturation and successful interaction between male and female gametes as reflected by the results of fertilization rate and embryo cleavage.
1,4-Dichlorobenzene (pDCB), dissolved in olive oil, was administered orally to two generations of rats to detect possible effects of the test substance on reproduction (OECD guideline 416). The doses used for the three test substance groups were 30, 90 and 270 mg pDCB per kg body weight. Olive oil was applied to one negative control group. Dose volume was 1 ml per kg body weight for all groups. In both generations the test substance had no effects on: time between beginning of mating and evidence of copulation, time of gestation, fertility index, gestational index, percentage of dams with only dead pups, total number of pups at birth, percentage of pups with positive ear reflex, grasping reflex and orientation reaction, absolute and relative weights of testes, epididymides and ovaries, absolute and relative weights of female kidneys, spleens and livers. In the mid and/or high-dose groups the test substance had an effect on: number of live pups at birth (reduced), number of pups deceased between days of lactation 1 to 4 and 5 to 21 (increased), mean body weight of pups (reduced), erection of ears and opening of eyes (retarded), percentage of pups with positive draw up test (reduced), alterations of the skin (dry, squamous) and ring tails in pups, absolute and relative organ weights of adult males (livers and kidneys: increased; spleens: reduced). Damages to the kidneys in mid- and high-dose groups of both generations are also probably test substance related. At the low dose of 30mg pDCB per kg body weight--equivalent to the actual MAK-value of 450 mg/m3 (exposure by inhalation)--no effects of the test substance were detected on fertility parameters of rats. The next higher dose of 90 mg/kg already caused massive damage in pups. Therefore, a reduction of the actual MAK value should be taken into consideration.
The neurotoxic effects of monosodium glutamate (MSG) on certain parts of the central nervous system (CNS) and endocrine functions are well documented. MSG-treated rats exhibit stunted growth, obesity and decrease in sexual behavior. The present study was designed to evaluate how neonatal administration of MSG affects sex-odor attractivity and approach behavior, and to investigate factors limiting copulation in MSG-treated rats. In this experiment, subcutaneous injections of MSG (400 mg MSG/ml normal saline/0.1 Kg B.W.) were given to Long-Evans pups on days 1 and 3 after birth, whereas the control groups received normal saline injections of equal volume (1 ml/0.1 kg B.W.). When the rats were 3 months old, sex-odor attractivity and approach behavior were tested. Two points were displayed by MSG-treated rats: (a) attenuated the attractivity of sex-odor. (b) decreased performance of sexual approach to partners. From our results and those of a previous study, we suggest that the deterioration of sex-odor attractivity and approach behavior to partners is attributed to a decline in sexual hormones. Furthermore, we concluded that this decrease in behaviors is to some extent responsible for reduced copulatory behavior.
The author estimated the impact of exogenous testosterone administration (1 mg/kg) to the male rats on the postnatal development of their offspring. The males were copulated with intact females 48 and 2 days after injection. The treatment of the male rats with testosterone 2 days before mating caused disorders in the sexual development and behavior formation of offspring of both sexes. The exogenous testosterone effects on spermatoblasts of the father promoted to the development of disorders in the formation of behavioral and emotional activities only in the female offspring.
Contractile elements are found in the ovaries of many species, but it has not been possible to ascertain whether these elements are of importance in the process of ovulation. In this report, we describe changes in intraovarian pressure recorded continuously in vivo in unanesthetized rabbits under normal conditions and under the influence of intravenously injected human chorionic gonadotropin (hCG), as well as following the ovulatory stimulus of normal copulation. The recordings were made by means of small latex balloons (0.02- to 0.04-ml volume) attached to indwelling catheters, inserted into the ovarian stroma, and secured with 6-0 nylon sutures. All 24 rabbits studied showed changes in intraovarian pressure indicative of ovarian contractile activity. The intraovarian pressure changes followed a characteristic pattern which was different from the changes in intratubal pressure, recorded simultaneously from the lumen of the ipsilateral fallopian tube, indicating that the contractions of both organs occurred independently. In normal animals, before an ovulatory stimulus was applied, the ovarian contractility pattern consisted of a series of rapid contractions (average amplitude, 6 mm Hg; average frequency; 8 per minute) occurring with intervals of quiescence lasting from 11 to 36 minutes. The base line tonus was frequently elevated during these series of contractions. Mating or an injection of hCG had no immediate effect on intraovarian pressure but, 6 to 8 hours after the stimulus was applied, ovarian contractile activity increased significantly in all rabbits. This enhanced activity persisted for several hours before returning to initial levels approximately 15 to 18 hours after mating or the hCG injection. This demonstration of increased contractile activity about the time of ovulation suggests that ovarian contractions participate in the process of follicular rupture and the extrusion of ova at ovulation. Prostaglandin F2alpha, norepinephrine, and oxytocin were effective in inducing ovarian contractions.
Effects of medial amygdala lesions (MAL) were examined on rat penile erection in three different experimental situations. Only sexually vigorous males, as identified by preoperative mating tests, were used. Bilateral radiofrequency lesions were confined to the posterior medial amygdala, with little systematic damage to anterior medial amygdala or to adjacent structures. Lesion electrodes were withdrawn without current application in sham-operated animals (SHAM). After recovery for brain surgery, males were tested for (1) noncontact erection (NCE) that occurs when males were placed in proximity to inaccessible estrous females, (2) reflexive erection evoked in supine males by retraction of the penile sheath, and (3) copulatory behaviour with receptive females. In the NCE test, none of the MAL males showed penile erection during the 20 min observation, whereas 70% of the SHAM males showed it (P < 0.001). In contrast, no erectile dysfunction in the MAL males was detected in the other two tests. MAL males displayed more penile-body erections (flips) than SHAM males in the reflexive-erection test (P <0.05). In the copulation test, most of the MAL males achieved intromission, but their intromission ratio, a partial measure of erectile function, was marginally lower than that of SHAM males (P = 0.051). MAL males had longer intervals between intromissions (P < 0.001); as a result, none of them ejaculated during the 30 min period that followed the first intromission. The results suggest that the posterior medial amygdala plays an essential role in the regulation of NCE, and it may also contribute to the regulation of erection in other contexts.
In previous work, we found effects of prenatal exposure to diazepam (DZ) on sexual behavior of adult mice. The aim of this work was to compare sexual behavior during their reproductive span of CD-1 strain male mice exposed in utero to DZ. One group of female mice was treated with DZ (2.5 mg/kg/day; s.c.) from 6th to 17th days of gestation and a control group received saline. The spontaneous offspring male sexual activity to receptive females was tested in 3 sessions (1/week) twice, on the 6th month of age and later on the 20th. Tests were performed during the dark stage of the photoperiod and video recorded under red light. During copulating stage adult DZ-treated males showed greater incidence of interruptions of intravaginal penetration, while senile DZ-treated males had lower latencies of mount series and greater proportion of ejaculations. Both adult and senile DZ-treated males exhibited a significant larger incidence of falls and pauses during mount series with intromission. Results show a permanent effect of prenatal exposure of DZ on sexual behavior.
In the male Syrian hamster, mating is dependent on chemosensory and hormonal stimuli, and interruption of either input prevents copulation. The medial amygdaloid nucleus (Me) is a key nodal point in the neural circuitry controlling male sexual behavior because it relays both odor and steroid cues. Me is comprised of two major subdivisions, anterior (MeA) and posterior (MeP), which have distinct, although overlapping efferent projections. The present study investigated the afferents and efferents of MeA and MeP by using combined anterograde and retrograde tract tracing. Phaseolus vulgaris-leucoagglutinin and cholera toxin B were injected by iontophoresis through a single glass micropipette and detected by immunohistochemistry. MeA has widespread connections with olfactory structures, whereas MeP is heavily interconnected with steroid-responsive brain regions. The efferent projections of MeA and MeP were similar to those reported previously for the rat and hamster. In particular, MeP projects to the posteromedial subdivision of the bed nucleus of the stria terminalis (BNST) and to the medial preoptic nucleus, whereas MeA projects to adjacent subnuclei in BNST and the preoptic area. MeA and MeP also have distinct patterns of afferent input. Furthermore, the combination of anterograde and retrograde tract tracers shows that MeA and MeP are each bidirectionally connected with each other and with limbic nuclei. These results demonstrate that subnuclei of Me are interconnected with limbic structures in hamster brain. These connections may contribute to chemosensory and hormonal integration to control male sexual behavior.
BACKGROUND: Whereas the secretion of the male vesicular gland in most mammals is amorphous, that of the tree shrew, Tupaia glis, was observed to be stored as globules. METHODS: Vesicular and prostate glands from Tupaia, fixed in glutaraldehyde and osmium, were studied in the light and electron microscopes. Other materials considered included the Tupaia ejaculate produced by electroejaculation and, for comparative purposes, sections of the vesicular gland from a dermopteran, the flying lemur. RESULTS: The vesicular gland epithelium in Tupaia secretes small granular aggregates and occasionally a denser aggregate that is associated with cells having obvious apical Golgi lamellae. In the alveolar lumen, these aggregates unite with others to form, respectively, granular and some dense globules of up to approximately 15 mu in diameter, which appear as such in semen produced by electroejaculation. In contrast to the prostate, however, precursor secretion vesicles were rare in the vesicular epithelium. Although poorly fixed, the vesicular gland secretion from a flying lemur also appeared to form globules. CONCLUSIONS: Although it is unlike the homogeneous secretion elaborated in most mammals, including primates and insectivores, the globular product of the Tupaia vesicular gland seems comparable to that in a variety of mega- and microbats, among representative species of which it appears to provide the bulk material for the vaginal copulation plug. Because a museum specimen examined here also indicates its occurrence in a flying lemur, the globular vesicular gland secretion common to Tupaiidae, to at least some Mega- and Microchiroptera, and apparently to Dermoptera may provide a soft tissue feature of some value in the cladistic approach to phylogenetic reconstruction within the Archonta. Anat.
BACKGROUND: Despite the importance of the rabbit (Oryctolagus cuniculus) in reproductive research, no comprehensive account of the anatomical organization of the female reproductive tract is presently available. METHODS: Based on gross dissection and on the electrical stimulation of striated muscles in 10 domestic female rabbits, it was the aim of this study to help fill this gap by describing the origin, insertion, and general action of muscles associated with the vaginal tract and with associated scent glands. RESULTS: Compared with the better-studied rat or cat, the long vaginal tract of the rabbit is characterized by a well-developed and complex musculature. The bulbospongiosus, ischiocavernosus, constrictor vestibuli, and constrictor vulvae muscles, poorly developed or absent in the female rat or cat, were particularly conspicuous. Scent glands, including the newly identified preputial glands, were also a distinctive feature. CONCLUSION: These structures may represent specializations underlying the rapid copulation, rapid parturition, and well-developed chemical communication characteristic of the reproductive efficiency of the rabbit.
Zambian common mole-rats are subterranean rodents that live in families with only one female breeding. Her offspring remain in the parental nest and do not reproduce. Behavioral experiments (Burda, '95) demonstrated that their apparent "sterility" is based on incest avoidance and individual recognition of family members. To elucidate whether some kind of morphologically apparent ovarian suppression still takes place in daughters, ovaries of females of known age, weight, and reproductive histories were examined histologically and morphometrically. The body mass of old females (more than 3 years of age) begins to decrease, and the ovaries seem to begin to atrophy at the age of about 3-6 years. Ovaries in neonates exhibited primordial and primary follicles, sometimes clustered in nests. Ovaries of adult nonbreeding females expressed all stages of the follicular development up to tertiary follicles. Many unruptured luteinized follicles were present, but true corpora lutea as a morphological sign of ovulation were missing. Unruptured luteinized follicles also could be found (additionally to true corpora lutea) in ovaries of breeding females. The number of primordial follicles dropped rapidly during the first 2 years of age; the number of primary, secondary, and tertiary follicles was subject to individual variation; and there was no clear correlation with age or reproductive status. While a tendency to form accessory unruptured luteinized follicles may just reflect taxonomic affinities of bathyergids to hystricomorphs, the otherwise complete folliculogenesis in "sterile" daughters and the presence of unruptured luteinized follicles even in breeding females are further evidence that there is no hormonal suppression of the ovarial cycle. We suggest that ovulation in nonbreeding females is not actively suppressed by the breeding female, but instead that it is not released because the triggering mechanisms, most probably repeated copulation, are missing.
We have previously studied the relationship between social subordinance (by approach-avoidance criteria) and physiology among male olive baboons (Papio anubis) living freely in a national park in Africa. In stable hierarchies, subordinate individuals have elevated basal glucocorticoid concentrations and a blunted glucocorticoid response to stress, as well as a prompt suppression of testosterone concentrations during stress. These facets have been interpreted as reflecting the chronic stress of social subordinance. In the present report, we find these endocrine features do not mark all subordinate individuals. Instead, endocrine profiles differed among subordinate males as a function of particular stylistic traits of social behavior. A subset of subordinate males was identified who had significantly high rates of consortships, a behavior usually shown only by high-ranking males. Such behavior predicted the beginning transition to dominance, as these males were significantly more likely than other subordinates to have moved to the dominant half of the hierarchy over the subsequent 3 years. In keeping with this theme of emerging from subordinance, these individuals had also significantly larger glucocorticoid stress-responses, another feature typical of dominant males. However, these subordinate males also had significantly elevated basal glucocorticoid concentrations; it is suggested that this reflects the stressfulness of their overt and precocious strategy of reproductive competition. In support of this, subordinate males with high rates of covert "stolen copulations" did not show elevated basal glucocorticoid concentrations. A second subset of subordinate males were the most likely to initiate fights are to displace aggression onto a third party after losing a fight. these males had significantly or near-significantly elevated testosterone concentrations, compared to the remaining subordinate cohort. Moreover, these males had significantly lower basal glucocorticoid concentrations; this echoes an extensive literature showing that the availability of a displacement behavior (whether aggressive or otherwise) after a stressor decreases glucocorticoid secretion. In support of this interpretation suggesting that it was the initiation of these aggressive acts which attenuated glucocorticoid secretion, there was no association between glucocorticoid concentrations and participation (independent of initiation) in aggressive interactions. Thus, these findings suggest that variables other than rank alone may be associated with distinctive endocrine profiles, and that even in the face of a social stressor (such as subordinance), particular behavioral styles may attenuate the endocrine indices of stress.
Cercopithecus, the genus of guenons, is the largest of the African primate genera, and yet more than half of the species belonging to this group have never been the focus of a long-term field study. In this paper, I present data on group size and composition for a previously unstudied population of guenons on the Caribbean island of Grenada. The mona monkey, Cercopithecus mona, was introduced to Grenada from Africa approximately 200-300 years ago. Two types of social groups were found for Cercopithecus mona on Grenada: all-male groups consisting of two to four individuals and bisexual groups containing 5-32 individuals. All-male groups of Grenada mona monkeys contained any combination of juveniles, subadults, and/or adults. All-male groups were a common occurrence on Grenada but have never been reported for African C. mona and have been reported only in two other forest Cercopithecus species. Bisexual groups appeared to consist of one adult male, one to six adult females, subadult females, and juveniles and infants of both sexes. Even though no more than one adult male was ever seen in each bisexual group of monas on Grenada, other males were heard giving copulation calls simultaneously with resident adult male loud calls, suggesting that other males occasionally infiltrate bisexual groups.
Microcebus murinus, a small nocturnal lemur from Madagascar, has retained features of ancient primates. Based on these ancestral traits, its social organization has often been used as a model for early primate social systems. In captivity it breeds polygynously, i.e., one male mates with several females, while females usually copulate only with the dominant male. The present project tested whether or not sexual size dimorphism, spatial distribution, and relative testis size of M. murinus correspond with predictions of the sexual selection theory concerning polygynous mating systems. The study was combined with a mark-recapture study and radio tracking of 12 animals in 1993 in a dry deciduous forest of western Madagascar at the end of the dry season. Large overlapping home ranges in males, lack of sexual size dimorphism, and relatively large testes suggest a multi-male mating system, i.e., one that is promiscuous rather than polygynous.