Characterization of the secretory proteins of rat preputial gland in relation to urinary proteins

The water-soluble proteins of the rat preputial gland secretion were characterized in native and SDS-treated form on polyacrylamide gel electrophoresis. Nine major proteins were present in the secretion. One protein was a glycoprotein of molecular weight greater than 200,000 with beta-glucuronidase activity, and the other eight proteins had a molecular weight of 17,000, but with different charges. Acid phosphatase and arylsulphatase activities were present in the secretion in minor amounts. The isoelectric points of the secretory proteins ranged from 8.5 to 5.3; none of the proteins were lipoproteins, and there were no sex differences. The male and female rat urinary proteins were also characterized electrophoretically. The male rats had two different protein patterns, probably genetically determined. The female rats showed basically one urinary protein pattern, but their urines were frequently mixed with the preputial gland secretory proteins, which most likely played a part in the chemical communication. The mixing could not be correlated to daytime or estrous cycle.     

在自然状态下黄毛鼠包皮腺的引诱力及季节变化

黄毛鼠(Rattus rattoides Hodgson)包皮腺成对位于下腹部的皮下,腺体开口于尿道口外包皮内的两侧。腺体形态,雌雄各异。雌性呈豆瓣形;雄性呈瓜籽形。体长150毫米以上的成年鼠,其包皮腺的长和宽约18和9毫米。包皮腺是动物的一个外激素释放源,对于种群的调节有着重要的作用(Christiansen ＆ Dving 1975)。关于它的性引诱作用见诸于Bronson ＆ Caroom(1971)、刘炳谦、刘素霞(1979)等。但在自然情况下包皮腺分泌及其引诱作用尚少报道。本文通过野外试验,初步研究了黄毛鼠包皮腺的分泌及引诱力的变化规律,探讨利用此特性的可能性。无疑,这对进一步研究外激素对种群调节作用以及鼠害防治方面是有意义的。     

Identification of alpha-2u globulin in the rat preputial gland by MALDI-TOF analysis

The low molecular mass proteins found in the pheromonal sources such as urine, saliva, glandular secretion etc have been reported as ligand carriers for the processes of chemocommunication in mammals. The preputial gland plays an important role in the production of olfactory signals for pheromonal communication. Thus, in the present study, alpha-2u globulin having molecular mass of 18 kDa has been identified in the preputial gland of Norway rat (Rattus norvegicus) by in-gel trypsin digestion and analyzing the resulting peptides by MALDI-TOF. Since preputial gland is one of the major pheromonal sources in rat, the results suggest that alpha-2u globulin might act as a carrier for hydrophobic odorants of preputial gland.     

两种兔尾鼠的化学信息及其在群体中的作用

黄兔尾鼠(Lagurus lutens)及草原兔尾鼠(Lagurus lagurus)是新疆某些地区主要害鼠之一,它们的繁殖能力很强,数量高峰时,对草场危害极大。此外,它们还能传染某些地方性流行病,所以对这两种害鼠的防治是十分必要的。 近年来,我们在研究动物化学通讯的过程中,了解到外激素(信息素)在动物间传递信     

Identification of glandular (preputial and clitoral) proteins in house rat (Rattus rattus) involved in pheromonal communication

Proteins (18-20 kDa) belonging to lipocalin family have been reported to act as carriers for ligands binding to pheromones in mouse urine, pig saliva, hamster vaginal fluid and human sweat, that are involved in pheromonal communication. As the preputial gland is a major pheromonal source, the present study was aimed to detect the specific protein bands (around 18-20 kDa) in the preputial and clitoral glands of the house rat, R. rattus. The amount of protein was higher in preputial gland of the male than that of female (clitoral) gland. A 20 kDa protein was noted in male and female glands; however, the intensity of the band was much higher in male than in female. In addition, 70, 60, 35 kDa bands, identified in male preputial gland, were absent in females. The presence of higher concentration of glandular proteins in the male preputial gland suggests that male rats may depend more on these glandular proteins for the maintenance of reproductive and dominance behaviours. The results further suggest that these glandular proteins (20 kDa) may act as a carrier for ligand binding.     

Reproductive biology of the greater bandicoot rat Bandicota indica （Rodentia： Muridae） in the rice fields of southern Thailand

This study investigated some aspects of the reproductive biology of male and female greater bandicoot rats,Bandicota indica,in southern Thailand from September 2004 to September 2006. In females,body,uterine and preputial gland weights,occurrences of pregnancies and placental scars,and in males,testicalar weights and histology,and sizes of accessory sex glands,were recorded. Pregnancies occurred predominantly,but not exclusively,in the wet season,with a higher incidence pregnancies in the second,than in the first,dry season. Uterine and preputial gland weights tended to be lower in the first,but not the second dry season,with placental scars occurring at all times of year. Males tended to have heavier testes in the wet season but some seminiferous tubules contained sperm even in the dry season. Seminal vesicles,but not prostates and preputial glands,tended to be heavier in animals in the wet season. We conclude that the greater bandieoot rat in southern Thailand shows maximal reproductive activity in the wet season with some reproductive activity,albeit variable from year to year,occurring in the dry season depending upon environmental conditions. This study has also shown that females,as well as males,have large preputial glands,and that males invariably have small testes regardless of the time of year. These observations suggest a similar timing of reproduction,but a different breeding biology and perhaps social organisation,from that of the sympatric ricefield rat,Rattus argentiventer.     

Identification of sex-associated protein in the preputial gland of house rat (a new insight in rodent pest management)

Our recent findings revealed that the preputial gland of male house rat contains 20 kDa protein, however, the role of androgen in the production of this protein is not known. Hence, the present study was carried out to evaluate the androgen dependency of 20 kDa protein in the preputial gland of house rat (Rattus rattus) and to compare its presence in female clitoral gland. Further, on castration the amount of glandular protein in male was significantly decreased to a certain extent, while testosterone treatment on castrated males showed an increasing trend. The electrophorogram of male house rat showed six different protein fractions with molecular weights of 90, 70, 60, 50, 35 and 20 kDa. However, the 70, 60, 50 and 35 kDa were absent in female. Among the different fractions, 90 and 20 kDa proteins were prominent. On castration, the 20 kDa protein was disappeared; while on testosterone treatment the protein reappeared. Thus, the present study concludes that the 20 kDa protein is a testosterone dependent sex-associated protein. Since urinary protein is found to act as carrier for volatile substances in pheromonal communication. The present study suggests that the glandular protein may bind with the volatile compounds produced from preputial gland. Identification of this carrier protein in the preputial gland explores the possibility of developing pheromonal trap for rodent pest management (RPM).     

Leucine aminopeptidase (LAP) activity and sexual dimorphism in rat exorbital lacrimal gland

Leucine amonopeptidase (LAP) activity was histochemically studied in the rat exorbital lacrimal gland. The enzyme is present in the secreting cells of both male and female prepuberal rats, in vivo and in monolayer cultures, while in the adult rat it is demonstrable only in the female. Furthermore, LAP is influenced by the sex hormones, disappearing in the female gland after testosterone treatment and appearing in the adult male gland after administration of estradiol or cyproterone acetate. These results show that the behaviour of LAP can be considered as another character of sexual dimorphism of the rat exorbital gland. Furthermore, our findings, showing an inverse relationship between LAP activity and the PAS positivity of the secretion products, suggest the hypothesis that the presence of this exopeptidase could induce qualitative modifications of one or more secreted glycoprotein.     

Sex- and gonad-affecting scent compounds and 3 male pheromones in the rat

This study was aimed at identifying sex pheromones of the rat (Rattus norvegicus). We characterized the volatiles and semivolatiles of rat preputial gland and voided urine by using gas chromatography-mass spectrometry (GC-MS) and quantified them by their GC areas (abundances) and percentage of GC areas (relative abundances). Although all the compounds other than 4-heptanone and phenol detected were shared by males and females, the quantities for some of these sex-common compounds exhibited sexual dimorphism and decreased with gonadectomy. Thus, these compounds might be sex pheromones. Among them, squalene from preputial glands and 2-heptanone and 4-ethyl phenol from urine were 3 major compounds. They were richer in males and could be suppressed by castration. Adding any of the 3 compounds (at a concentration higher than its physiological level in male urine) to castrated male urine (CMU) increased the attractiveness of CMU to sex-naive females. Adding the 3 together (at the levels in normal male urine) to CMU significantly increased the attractiveness of CMU to females. However, such combination did not fully restore females' preference for urine from intact males, suggesting that some other trace compounds such as 4-heptanone and phenol might also play some roles in sex attractiveness. Thus, squalene, 2-heptanone, and 4-ethyl phenol were indeed male pheromone molecules in rats. Our study also indicates that E,E-beta-farnesene and E-alpha-farnesene, both richer in females than males, might be putative female pheromones.     

Influence of sex on gastric acid secretion and parietal cell mass in the rat

The role of sex on the development and function of parietal cell was investigated in the rat. Basal gastric acid secretion and parietal cell mass were found to be significantly lower in female rats than in male. The results suggest that sex is an important factor influencing the growth and function of the gastric mucosa.     

Sex hormone regulation of anti-bacterial activity in rat uterine secretions and apical release of anti-bacterial factor(s) by uterine epithelial cells in culture

In mature female rats, sex hormones regulate the reproductive (estrous) cycle to optimize mating and fertility. During the part of the estrous cycle when mating occurs, and when estrogen is the dominant sex hormone, the uterus is susceptible to infection with bacteria that can be deleterious for survival and fertility. The present study investigated whether sex hormones regulate innate immunity in the female reproductive tract by affecting the secretion of an anti-bacterial factor(s) in the rat uterus. Uterine fluids from intact rats at the proestrous stage of the estrous cycle significantly inhibited Staphylococcus aureus growth. When ovariectomized rats were treated with estradiol, anti-bacterial activity against both S. aureus and Escherichia coli increased in uterine secretions with hormone treatment. In contrast, rats injected with either progesterone and estradiol or progesterone alone displayed no bactericidal activity indicating that progesterone reversed the stimulatory effect of estradiol on anti-bacterial activity. In other studies, isolated uterine epithelial cells from intact animals were grown to confluence and high transepithelial resistance on cell inserts. Analysis of apical secretions indicated that a soluble factor(s) is released by polarized epithelial cells which inhibits bacterial growth. These results demonstrate that sex hormones influence the presence of a broad-spectrum bactericidal factor(s) in luminal secretions of the rat uterus. Further these studies suggest that epithelial cells which line the uterine lumen are a primary source of anti-bacterial activity.     

Loss of growth hormone-dependent characteristics of rat hepatocytes in culture

Summary The liver of rodents is sexually differentiated, i.e. the female liver differs from the male liver. This differentiation is largely controlled by the pattern of growth hormone (GH) secretion. We have attempted to maintain GH-dependent differentiation of cultured rat hepatocytes. We examined the level of alcohol dehydrogenase (ADH) activity, which responds to GH and is higher in female than in male liver, and the estrogen receptor, which is dependent on GH but is present in equal amounts in males and females. ADH activity was maintained in cells from male rats, but fell by 40% in cells from females in medium supplemented with insulin and dexamethasone. The estrogen receptor content of female cells fell dramatically to undetectable levels within 2 d of culture. Extensive supplementation of the medium failed to prevent the decrease in ADH activity in female cells; similarly, the addition of female sex steroids; rat serum; pituitary extracts; rat, human, or bovine GH; or ovine prolactin failed to maintain the enzyme activity. Insulin, dexamethasone, thyroid hormone plus GH or prolactin, or the combination of all five hormones also failed to prevent the loss of estrogen receptors. Short-term cultures of rat hepatocytes, although retaining the liver-specific expression of ADH at the male level, lose GH-dependent expression of the estrogen receptor and stimulation of ADH activity. Supported by grants AA 00081 and AA 06434 from the National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD.     

A Computational Model to Predict Rat Ovarian Steroid Secretion from In Vitro Experiments with Endocrine Disruptors

A finely tuned balance between estrogens and androgens controls reproductive functions, and the last step of steroidogenesis plays a key role in maintaining that balance. Environmental toxicants are a serious health concern, and numerous studies have been devoted to studying the effects of endocrine disrupting chemicals (EDCs). The effects of EDCs on steroidogenic enzymes may influence steroid secretion and thus lead to reproductive toxicity. To predict hormonal balance disruption on the basis of data on aromatase activity and mRNA level modulation obtained in vitro on granulosa cells, we developed a mathematical model for the last gonadal steps of the sex steroid synthesis pathway. The model can simulate the ovarian synthesis and secretion of estrone, estradiol, androstenedione, and testosterone, and their response to endocrine disruption. The model is able to predict ovarian sex steroid concentrations under normal estrous cycle in female rat, and ovarian estradiol concentrations in adult female rats exposed to atrazine, bisphenol A, metabolites of methoxychlor or vinclozolin, and letrozole.     

Sex preference and species specificity of rodent (Mus musculus and Microtus arvalis pheromones.

The behavioural response to the sex pheromones in the externally voided urine of field voles (Microtus arvalis) and laboratory mice (CFLP, CBA strains) although specific for species showed no strain specificity. Bladder urine (free of accessory sex-gland secretions) and the preputial glands of CFLP and CBA mice contain sex attractants. Ether extracts made of blood of male CFLP mice attracted CFLP female mice.     

Der Einfluss verschiedener Fixierungsmittel auf das Strukturbild der Präputialdrüsen der Ratte

Summary The influence of various methods of fixation on the preputial gland of the rat was investigated. In addition to the lipids, the cells contain numerous granules which are dissolved by alcoholic and certain acid fixatives. In future investigation concerning either the histochemistry of the gland or the effect on the gland of various experimental conditions, its peculiar ability to secrete two different substances must be considered. In any event the preputial gland of the rat is more than a simple sebaceous gland.     

Metabolic modulation induced by oestradiol and DHT in immature rat Sertoli cells cultured in vitro

Sertoli cells actively metabolize glucose that is converted into lactate, which is used by developing germ cells for their energy metabolism. Androgens and oestrogens have general metabolic roles that reach far beyond reproductive processes. Hence, the main purpose of this study was to examine the effect of sex hormones on metabolite secretion/consumption in primary cultures of rat Sertoli cells. Sertoli cell-enriched cultures were maintained in a defined medium for 50?h. Glucose and pyruvate consumption, and lactate and alanine secretion were determined, by 1H-NMR (proton NMR) spectra analysis, in the presence or absence of 100?nM E2 (17β-oestradiol) or 100?nM 5α-DHT (dihydrotestosterone). Cells cultured in the absence (control) or presence of E2 consumed the same amount of glucose (29±2?pmol/cell) at similar rates during the 50?h. After 25?h of treatment with DHT, glucose consumption and glucose consumption rate significantly increased. Control and E2-treated cells secreted similar amounts of lactate during the 50?h, while the amount of lactate secreted by DHT-treated cells was significantly lower. Such a decrease was concomitant with a significant decrease in LDH A [LDH (lactate dehydrogenase) chain A] and MCT4 [MCT (monocarboxylate transporter) isoform 4] mRNA levels after 50?h treatment in hormonally treated groups, being more pronounced in DHT-treated groups. Finally, alanine production was significantly increased in E2-treated cells after 25?h treatment, which indicated a lower redox/higher oxidative state for the cells in those conditions. Together, these results support the existence of a relation between sex hormones action and energy metabolism, providing an important assessment of androgens and oestrogens as metabolic modulators in rat Sertoli cells.     

Sex differences in the accumulation of estrogen receptors in nuclei of liver cells and increase of angiotensinogen concentration in the blood of rats after administration of low doses of synthetic estrogens

The significance of sex differences in the level of estrogen receptors (ER) in hepatocytes for direct effects of estrogens in male and female rat livers was investigated. 4-5-fold increase in ER level and 20-30%-elevation in plasma angiotensinogen (AG) occurred after a single injection of 0.5 microgram of hexestrol (HE) in female and gonadectomized male rats. In male liver, where the cytosol ER content is two fold lower than that in female rats, nuclear ER level was shown to be very low and unchanged after HE injection, plasma AG also did not change. Injection of 0.5 microgram of ethinylestradiol produced similar effect. Injection of a greater dose of estrogen caused an enhancement in plasma AG level in males. The existence of sex differences in hepatic ER level seems to cause in some conditions different response of metabolic processes in male and female rat liver after estrogenization.     

Microtransferrinuria and microalbuminuria. II. In the rat

We studied albumin and transferrin excretion in the normal and diabetic rat: (1) The rat secretes small concentrations of albumin and transferrin in the urine. (2) The secretion depends on the strain and was highest in the Kyoto spontaneously hypertensive rat. (3) The secretion of these two proteins in the rat is quite dependent on age and sex. The level increases dramatically with age. The secretion is much higher in the male compared to the female. This difference is observed after puberty. The changes in transferrin relative to those in albumin are much higher. (4) In streptozotocin-induced diabetes, the concentration of albumin and transferrin expressed as milligrams per liter decreases; however, the output/24 h or per gram creatinine is increased with a greater increase in transferrin output relative to that of albumin. The similarities and differences between excretion of these two proteins in the human and the rat as well as their importance are discussed.     

四川短尾鼩包皮腺的挥发性化学成分分析

哺乳动物的包皮腺分泌物对个体间性引诱及繁殖行为的信息交流和种群调节有着重要的作用。本研究以四川短尾鼩（Anourosorex squamipes）为研究对象对劳亚食虫目动物包皮腺挥发性化学成分和化学通讯功能进行报道。采用顶空固相微萃取—气质联用（HS-SPME-GC/MS）的方法,分析四川短尾鼩雄体包皮腺中挥发性物质的化学组成。结果表明：（1）四川短尾鼩雄体包皮腺的挥发性化学成分主要含烷烃类、醇类、酮类、醛类、醚类、酯类、酸类、芳香烃类等45种化合物;（2）成年雄性四川短尾鼩的包皮腺中挥发性成分有39种,幼年雄性含有28种,说明四川短尾鼩成年雄体的包皮腺中挥发性化学成分多于幼年雄体;（3）成年雄体的包皮腺分泌物中含有4种特有的挥发性化学成分,幼年雄体中特有成分仅为1种,表明四川短尾鼩包皮腺中的挥发性化学成分存在年龄差异;（4）四川短尾鼩包皮腺分泌物中不同化学成分相对含量不同,同种化学成分在不同个体间的相对含量存在差异。四川短尾鼩雄性包皮腺挥发性化合物种类丰富,个体、年龄差异明显。推测挥发性化合物中丁酸（Butanoicacid）、乙酸乙酯（Ethyl acetate）、苯酚（Phenol）为四川短尾鼩的信息素。本研究为进一步验证该物种的信息素成分及其传递机制提供了基础数据。     

The effect of some hepatotoxins on the sulphoxidation of cimetidine in rat

Sulphoxidation of cimetidine was investigated in male and female rats after pretreatment with the hepatotoxins allyl alcohol, dl-ethionine, thioacetamide and carbon tetrachloride. There was a marked sex difference in cimetidine sulphoxidation in response to the hepatotoxin pretreatment. All the hepatotoxins enhanced cimetidine sulphoxidation in the male rat (P less than 0.01). Carbon tetrachloride and thioacetamide inhibited cimetidine sulphoxidation in the female rat (P less than 0.01) but dl-ethionine and allyl alcohol had no effect on this metabolic pathway.