Sexual Skin Research Articles

Sexual Behaviour of Sumatran Long‐tailed Macaques (Macaca fascicularis)

AbstractThe sexual behaviour of wild long‐tailed macaques (Macaca fascicularis) was studied in the Gunung Leuser National Park, Sumatra, Indonesia. All females showed some swelling of the sexual skin, but the frequency and maximum size of the swelling decreased with age. The frequency of copulations and consortships for a given female increased with increasing degree of swelling or coloration. No regular cycles could be found in the occurrence of swellings, copulations and consortships. Periods for which a female had consortships tended to be long (up to 5–6 weeks on end). These two results suggest that in the wild the predictability of the moment of ovulation is very low. The consortships were not exclusive: both the male and the female occasionally copulated with others. All females had many different male partners and, as ovulation signalling was not clear, none of these males could have any certainty about paternity of a female's offspring. Yet, the highest‐ranking males probably had the best chances to father children because they were more often involved in sexual interaction (both copulations and consortships), especially around the estimated date of conception. This does not hold for the nulliparous females who were virtually ignored by the higher‐ranking males. Consortships were occasionally actively maintained by the female, for whom a direct advantage of consorting might be an increased safety against conspecifics and predators. One advantage of mating with many different males might be a reduced risk of infanticide.

Effect of constant-release implants of melatonin on seasonal cycles in reproduction, prolactin secretion and moulting in rams

Seasonal cycles in the size of the testes, blood plasma concentration of testosterone, FSH and prolactin, intensity of the sexual skin flush, timing of rutting behaviour and moulting of the body coat were recorded in Soay rams after s.c. implantation of melatonin contained in a Silastic envelope which increased the circulating blood levels of melatonin to 200-600 pg/ml for many months. Two groups of 8 adult rams were held under alternating periods of short days (8L:16D) and long days (16L:8D) to drive the seasonal cycles and the treatments with melatonin were initiated during the long or short days, and one group of 8 ram lambs was kept out of doors and given implants during the long days of summer (4 melatonin-implanted and 4 control (empty implants) rams per group). The treatments demonstrated that melatonin implants during exposure to long days resulted in a rapid 'switch on' of reproductive redevelopment similar to that produced by exposure to short days melatonin implants prevented the rams from showing the normal responses to changes in the prevailing photoperiod rendering them nonphotoperiodic; and long-term cyclic changes in testicular activity, prolactin secretion and other characteristics occurred in the melatonin-implanted rams; the pattern was similar to that previously observed in rams exposed to prolonged periods of short days. The overall results are consistent with the view that melatonin is the physiological hormone that relays the effects of changing photoperiod on reproduction and other seasonal features, and that continuous exogenous melatonin from an implant interferes with the normal 'signal' and produces an over-riding short-day response.

Three successful cases of artificial insemination in chimpanzees

Artificial inseminations were performed on two female chimpanzees from July 1981 to April 1983 and three conceptions were obtained. Semen samples collected by rectal probe method of electroejaculation were incubated at 37 degrees C for about 20 minutes for liquefaction. Liquefied portion of the semen was sucked up into polyethylene tube about 30 cm in length attached to a syringe and was inseminated into cervix of each female of which pelvic region was raised in prone position under anesthesia. Ovulation time was speculated by swelling of sex skin in earlier two cases and by urinary LH level in last case. Three offsprings were obtained 234, 235 and 235 days after last insemination, respectively. All of three show normal developments.

Sex hormones and skin collagen content in postmenopausal women

Sex hormones and skin collagen content in postmenopausal women

Nuclear progestin receptor in the chimpanzee sex skin.

We describe for the first time the presence of a nuclear progestin receptor in the sex skin of the chimpanzee, which is possibly involved in the anti-estrogen action of progestins in the sexual swelling.

Posterior Hypothalamic Lesions Advance the Onset of Puberty in the Female Rhesus Monkey*

The effects of experimental lesions in the posterior hypothalamus and the anterior hypothalamus on menarche and first ovulation were examined in nonhuman primates. With the aid of x-ray ventriculography, bilateral lesions were made by passing a radiofrequency current through a thermister electrode in the posterior hypothalamus (n = 7) or the anterior hypothalamus (n = 6) of female rhesus monkeys at 18 months of age. Four animals that received sham lesions as well as four normal females of a similar age served as controls. All animals were caged individually and examined daily for vaginal bleeding and sex skin color change. Developmental changes in gonadotropins, ovarian steroids, body weight, and nipple size were monitored throughout the experiments. The time of first ovulation was determined by laparoscopic observation of the newly formed corpus luteum and by the level of circulating progesterone. Histological examination confirmed that the bilateral lesions in the hypothalamus were approximately 2-3 mm in diameter and overlapped midline. Primary sites of posterior hypothalamic lesions included the premamillary area and the posterior nucleus, while the infundibular nucleus and the median eminence were entirely spared. The posterior lesions encroached upon the mamillary nuclei caudally in most cases and upon the ventromedial nucleus rostrally in some cases. Primary sites of anterior hypothalamic lesions included the medial preoptic area, the periventricular preoptic nucleus, and the anterior hypothalamic nucleus. Partial lesions of the diagonal bundle of Broca, the medial preoptic nucleus, and the paraventricular nucleus were also detected. Posterior hypothalamic lesions advanced the ages at menarche (22.2 +/- 1.3 months; P less than 0.001) and first ovulation (40.7 +/- 2.7 months; P less than 0.05) compared to those of control animals (menarche, 30.3 +/- 3.1; first ovulation, 51.2 +/- 3.3 months). The body weight at menarche of these lesioned animals (2.62 +/- 0.11 kg) was smaller (P less than 0.05) than that of controls (3.14 +/- 0.20 kg), but the body weight at first ovulation of lesioned animals (4.36 +/- 0.28 kg) was not different from that of controls (4.57 +/- 0.13 kg). Hormonal and physical changes during maturation, i.e. an increase in circulating estradiol and growth in nipple size before menarche and first ovulation, occurred earlier in the lesioned animals and the growth spurt before first ovulation not only began earlier but also attained mature levels several months earlier than that in control animals.(ABSTRACT TRUNCATED AT 400 WORDS)

Central effects of photoperiod on reproduction in the ram revealed by the use of a testosterone clamp.

Over a 3-year period eight adult Soay rams were exposed to an artificial lighting regimen of alternating 16-week periods of long days (16 h light: 8 h darkness; 16L : 8D) and short days (8L : 16D) to induce a seasonal cycle in reproduction and wool growth every 32 weeks. Early in the study the rams were castrated (four during long days and four during short days) and 48 weeks later the castrated animals were each given an s.c. implant of testosterone to increase the blood plasma concentration of testosterone to 14-20 nmol/l. The changes in the concentrations of LH, FSH and testosterone were measured in blood samples collected once or twice weekly while records were made of the changes in the size of the testes (before castration), the intensity of the sexual skin flush, the expression of aggressive and sexual behaviour and the rate of wool growth. The results showed that in the castrated rams there were only minor changes in the blood levels of LH, FSH and the expression of aggressive behaviour related to the 32-week light cycle, while the sexual skin flush was permanently absent. However, after the commencement of the constant testosterone therapy, there were major changes in all the reproductive parameters related to the lighting regimen with a similar temporal relationship as observed in the rams before castration. Cyclic variation in wool growth occurred throughout the study related to the changes in photoperiod but this was not markedly affected by castration and testosterone replacement.(ABSTRACT TRUNCATED AT 250 WORDS)

Idiopathic Precocious Puberty in the Chimpanzee: A Case Report

A female chimpanzee developed premature sex skin swelling, breast budding, advanced bone age, and moderate estrogen effect of the vaginal cytology. Extensive radiographic and hormonal studies excluded all the known causes of precocious puberty and pseudopuberty, yielding a diagnosis of idiopathic true precocious puberty. To our knowledge this is the first observation of idiopathic true precocious puberty in a chimpanzee.

INCOMPLETE ANDROGEN INSENSITIVITY SYNDROME: PARTIALLY MASCULINIZED GENITALIA IN TWO PATIENTS WITH ABSENCE OF ANDROGEN RECEPTOR IN CULTURED FIBROBLASTS

In male pseudo-hermaphroditism due to end organ unresponsiveness, partial androgen insensitivity can usually be related to low but detectable dihydrotestosterone (DHT) binding activity in cultured sexual skin fibroblasts. We have studied two patients with partial virilization and total absence of androgen receptors in cultured fibroblasts. A lack of DHT binding could be related to a selection of a fibroblast strain with no androgen receptor activity, to insufficient sensitivity of the method in detecting very low receptor concentrations or to an instability of the receptor or the androgen-receptor complex. However, these observations raise the question of masculinization of external genitalia with undetectable androgen receptor.

The communicative function of palmar pigmentation in man

Mankind is unusual among primates in having little or no pigmentation on palms and soles, and unique in having unpigmented nails in adulthood. In many animals, coloration functions in social communication, as in the pale eyelids of some monkeys and baboons, or the sexual skin, as in female chimpanzees. It is suggested that depigmented volar skin and nails arose in the hominids to enhance the visibility of manual gestural communication, as well as of hand and finger movements involved in tool-making and tool-use.

Effect of estradiol-treated females on all-female groups of rhesus monkeys during the transition between the nonbreeding and breeding seasons.

Behavior, sex steroid levels and sex skin color were monitored in 2 out-door-housed all-female groups of rhesus monkeys during the nonbreeding season and into the breeding period. Each group contained gonadally intact and ovariectomized (OVX) females. In one group, 2 OVX females were implanted with estradiol benzoate pellets. Female-to-female sexual behavior, sex skin redness and endocrine indices of ovulation (in intact females) all increased as the breeding season approached. The two groups did not differ with regard to these measures. This lack of difference suggests that the presence of males may be required to mediate socially facilitated out-of-season breeding by females. No strong relationships were detected between steroid levels of intact females and sex skin color or female-to-female sexual behavior in all-female groups.

Estrogen receptors and estrogen-inducible progestin receptors in the sexual skin of the monkey

Estrogen-binding macromolecules were identified in sexual skin cytosol and nuclear fractions from female Japanese monkeys ( Macaca fuscata fuscata), by sucrose-glycerol gradient analysis and dextrancoated charcoal adsorption technique. Furthermore, using the highly potent synthetic progestin, R5020 (17,21-dimethyl-19-nor-4,9-pregnadiene-3,20-dione; promegestone), progestin-binding macromolecules were detected in sexual skin cytosols from ovariectomized estrogen-primed monkeys. Both cytosol components sedimented at the 8S region on sucrose-glycerol gradients and had a highaffinity for the respective steroids, and competition studies showed a specificity for estrogenic, or progestational compounds. The concentration of cytosol progestin receptors was markedly increased with the elevated level of nuclear estrogen receptors following estrogen priming. The above results demonstrate the existence of cytosol and nuclear estrogen receptor sites, and estrogen-induced progestin receptors in the sexual skin of the female monkeys.

Influences of ovarian hormones on the food intake and feeding of captive and wild female chacma baboons ( Papio ursinus)

The relationship between ovarian hormone changes and food intake was examined in three separate studies using captive intact, captive ovariectomized and wild intact chacma baboons ( Papio ursinus). Measures of body weight, perineal turgescence and food intake all varied across the menstrual cycle for a group of seventeen intact laboratory housed females. Body weights showed steady increases up until the day of sex skin detumescence or breakdown. Perineal swell ratings also showed a constant rise ending with breakdown. Food intake, however, showed a pattern of decrease until three days preceding breakdown. Statistical analysis revealed a significant difference between food intake during the preovulatory and luteal period phases. Exogenous estradiol benzoate (EB) and progesterone treatments to a group of ten ovariectomized females demonstrated an inhibitory effect of EB upon food intake. No effects for progesterone were demonstrated. A field study of two wild troops confirmed a difference in percentage of time spent feeding for females in the fully swollen condition as contrasted to those whose perineums were flat. Data collected on fully swollen females suggested that consort relations had little effect upon the females' feeding time percentages.

A 4-year summary of the nonsurgical recovery of baboon embryos: A report on 498 eggs.

A nonsurgical embryo recovery procedure, developed to allow the economical acquisition of cleavage stage baboon embryos, has been successfully used for 4 years. With this technique, 498 eggs have been recovered from 979 uterine flushes (50.9%) on 71 baboons. Of 467 eggs recovered from mated baboons, 290 (62.1%) were fertilized. Papio anubis females provided a higher percentage of fertilized eggs (75.3%) than did Papio hamadryas (47.8%) or Papio cynocephalus (44.3%) females following exposure to males during estrus, although sexual preference may be responsible for the reduced fertilization rate in the P. cynocephalus females. Recovery rates from individual baboons ranged from 0% (n = 11) to between 66% and 93% for ten baboons from each of which 12-33 eggs have been recovered. Fertilized eggs were at the two-cell (n = 23) to blastocyst (n = 53) stage at recovery 1-6 days postdeturgescence (PD) of the sex skin, with morulae (n = 84) being the most frequent cell stage recovered (30%). The optimum time for performing the procedure was the third day PD, when 113 (40%) embryos were recovered. The abilities of baboons to become pregnant and to provide fertilized embryos were significantly related (P < 0.005), allowing the embryo recovery technique to be used as a screening procedure for evaluating baboon fertility.

Influence of olfactory signals on the reproductive behaviour of social groups of rhesus monkeys (Macaca mulatta).

Olfactory influences are important in the control of reproductive function in many mammalian species including primates. Previous studies have shown that a mixture of volatile aliphatic acids (copulins), normally present in the vaginal secretions of rhesus monkeys, can exert a stimulatory effect on the sexual behaviour of males when pairs are tested in small cages. The present study deals with the role of these substances when tested in social groups of rhesus monkeys housed in a large testing arena, the purpose being to assess the effectiveness of olfactory signals under more nearly naturalistic conditions. Each group consisted of one male with four long-term ovariectomized females from which the male could choose. A counter-balanced experimental design was used in which each female of a testosterone-treated pair was given applications to the sexual skin of either copulins or control ether immediately before each 1-h behaviour test. After 16 tests, the procedure was repeated with the previously untreated pair in each group, and nine groups were separately studied. Testosterone was used here simply to enhance female proceptivity. The results showed that females received significantly more ejaculations (P less than 0.05), mounting attempts (P less than 0.01) and mounts (P less than 0.05) when bearing copulins than when bearing control ether. There were positive responses to copulins in 12 of the 36 males-females pairs, involving all males, and positive responses to ether in five of 36 pairs, involving four males. Copulins resulted in a change in the choice of sexual partner in five males, but there were no changes in the choice of partner with ether. Social factors, such as dominance, could override the responses to olfactory signals, and there was a significant treatment order effect, but this was eliminated by the counter-balanced design. These findings indicate a significant role for olfactory communication in mate selection in a socially living higher primate.

Androgen receptors in cultured human skin fibroblasts.

Human skin may be considered as a target organ for androgens, since events characteristic of androgen action have been described in this tissue, as well as in cultured human skin fibroblasts. The culture of human skin fibroblasts gives the opportunity to work on living cells, under controlled conditions, in a renewable material from a single skin biopsy. Using this method, we showed the presence od DHT-receptors in the human fetus and we studied the ontogenesis of androgen receptors in relation to sexual differentiation. In the neonatal period, the physiological T rise was not concurrent with a variation in sex skin androgen receptors. The evolution of DHT binding during puberty is now under investigation. These data suggest that the androgen receptor is not modulated by plasma androgens. Androgen receptor determination is of value in defining the biochemical defects involved in partial and complete androgen insensitivity syndrome (twenty-six cases in our study). In idiopathic hirsutism, DHT binding is used to detect an eventual local hypersensitivity. Fibroblast cultures have also been shown to be an excellent model for the screening of compounds which might block the expression of androgen action by competing for the androgen receptors. Cultured skin fibroblasts are a valuable model for the study of androgen and antiandrogen action in human skin.

Demonstration and characterization of estrogen receptor in chimpanzee sex skin: correlation between nuclear receptor levels and degree of swelling.

The presence of cytosol and nuclear estrogen receptors has been demonstrated in chimpanzee sex skin. Both receptors sedimented at approximately 4S in sucrose gradients containing 0.6 M KCl. Both had a steroid specificity and high affinity for estrogen that conform to an estrogen receptor. The absence of such receptors in the pigmented skin surrounding the sex skin and in the abdominal skin indicates their discrete localization in the sex skin. While the cytosol receptor remained low (less than 10 fmol/mg cytosol protein), the nuclear estrogen receptor showed a fluctuation during the menstrual cycle, attaining the highest level during the late follicular phase (90.4 +/- 8.4 fmol/mg nuclear extract protein; nearly 3-4 times the level during the early follicular and luteal phases). When ovariectomized animals were treated with mestranol, the concentration of nuclear estrogen receptor increased from below detection to 74 fmol/mg nuclear extract protein. An increase in serum progesterone during the luteal phase, despite concurrently elevated serum estradiol levels, was associated with a reduction of the nuclear estrogen receptor as was the administration of progesterone and mestranol to estrogen-primed ovariectomized animals. Changes in the concentration of the nuclear estrogen receptor were positively correlated with changes in the degree of the sexual swelling. These results strongly suggest that estrogen controls the sexual swelling by acting through specific receptors in the sex skin, and that counteraction by progesterone of estrogen stimulation of the sexual swelling is effected through a reduction in nuclear estrogen receptors.

Temporal relationship of hormonal peaks to ovulation and sex skin deturgescence in the baboon

The purpose of this study was to determine the temporal relationship of peak levels of oestradiol (E2), LH and progesterone to ovulation and sex skin deturgescence in the baboon. A total of 55 baboons were used in these studies. Hormonal levels were measured in 47 cycles and ovulation was documented by laparoscopic examination in 26 of these cycles. A temporal relationship of ovulation to sex skin deturgescence was established in 57 cycles. The mean interval from E2 peak to ovulation was 41.4±2.3 hr, the interval from E2 peak to LH peak was 17.3±2.0 hr and that from LH peak to ovulation was 18.4±2.0 hr. Eleven baboons showed an LH peak on the day of the E2 peak. The number of days to the first sign of sex skin deturgescence after ovulation was 2.07±0.14 days (range 0–5 days). Nineteen cycles (33.3%) showed sex skin deturgescence 1 day after ovulation, another 19 cycles (33.3%) showed sex skin deturgescence 2 days after ovulation, and only 13 cycles (22.8%) showed sex skin deturgescence 3 days after ovulation. Sex skin deturgescence was observed on day 0, 4 or 5 postovulation in only two baboons.

Hormonal regulation of sex skin in Macaca nemestrina.

Artificial menstrual cycles were produced in ovariectomized pig-tailed macaques (Macaca nemestrina) by a sequential estradiol-progesterone regimen. Cyclic changes in sex skin were correlated with systemic levels of estradiol and progesterone. The steroid levels were in the normal range, and the cyclic changes in skin turgor and structure were essentially identical to those found during natural cycles. During the artificial follicular phase, fibroblasts were large and filled with biosynthetic organelles; structures that represented the entire sequence of synthesis, packaging, and secretion of procollagen were found in these hypertrophied cells. In addition, collagen fibers became more dispersed, the amount of hyaluronidase-sensitive material increased, and the stratum corneum became thinner. During the artificial luteal phase, fibroblasts atrophied, collagen fibers became rearranged into bundles, ground substance decreased in amount, and the stratum corneum thickened. The sex skin in spayed, pig-tailed macaques provides a rich source of material in which to study the mechanism of hormone action. It can be driven by estradiol and progesterone to synthesize or degrade collagen and hyaluronic acid, and these end products and their morphological correlates can be monitored by biochemical and ultrastructural techniques.

A Computerized Health Profile Model for Adolescents

Since health-hazard appraisal systems have been aimed primarily at adult audiences the 4-H For Life Program was developed (in Florida) in order to help youth select lifestyles conducive to health at an early age in the hope of prolonging and improving the quality of their lives. The Program developed a computerized health hazard appraisal program for teenagers piloted in four rural and medically underserved Florida counties. The project was designed to address common health and safety concerns specific to the adolescent age group: accidents of all types suicide homicide stress depression unplanned parenthood abuse of drugs and alcohol smoking sex skin problems and obesity. The project provided a computerized health profile which could be used by youngsters to clarify their own values identify practices they would like to alter and promote lifestyles conducive to health. The project included individual counseling and health education classes as well as a survival skills course at a local 4-H camp. The mean health-risk score for all teens contacted by the project was 87.7 scores ranging from 39-100. Most teens lost points in these general areas when profiled: failure to practice safety habits alcohol and drug usage inadequate exercise and obesity. Other problem areas identified were stress and depression for 30% of those profiled lack of proper immunizations for 54% and failure to use contraceptive methods during sex for 62%. The computerized health profile model has produced encouraging results in demonstrating its utility as a tool for capturing adolescents concerns for making positive decisions about their lifestyles and their health. The results confirmed findings of other researchers regarding a low level of health education and health awareness however and they confirm the need for a more comprehensive health education program for the adolescent community.