On the use of the perineal stain as an index of sexual maturity and breeding condition in the male greater cane rat, Thryonomys swinderianus, Temminck

The efficacy of the perineal stain as an index for sexual maturity and breeding condition in the male greater cane rat, Thryonomys swinderianus, Temminck, was investigated in 34 animals collected from hunters' kills in the Ekumfi District of Ghana, between April and June 1989. The results indicated that, although the presence of the perineal stain was conclusive proof of sexual maturity in an individual, it was not efficacious as an index for sexual maturity for biological work in these animals (p > 0.05) because it excluded some that, although sexual mature, did not exhibit the trait, particularly young adults. However, the perineal stain may be useful as a management tool for identifying sexually mature captive greater cane rats. About 7 out of every 10 caught each month were found to be in breeding condition.

Anogenital gland secretions ofLemur catta andPropithecus verreauxi coquereli: A preliminary chemical examination

Although prosimians are greatly olfaction-oriented, little is known about the specifics of how they use scent to communicate. In this preliminary study we attempted to delineate intra- and interspecific differences among the anogenital gland secretions of two lemur species (Lemur catta and Propithecus verreauxi coquereli) using gas chromatography-mass spectrometry (GC-MS). The results indicate that the two species are discernible through scent. Furthermore, we were able to identify reproductive status using this technique. The anogenital secretions of the different sexes in L. catta, though perhaps not P. v. coquereli, are chemically distinguishable. Given this information, it appears that at least some lemur species can use scent marks to determine species, sex, and reproductive status.

Epidermal glands in Squamata: microscopical examination of precloacal glands in Amphisbaena alba (Amphisbaenia, Amphisbaenidae)

The femoral or cloacal region of many species of lizards and amphisbaenians exhibits epidermal glands. The pores of these glands are plugged with holocrine solid secretions that serve as semiochemical sources. Many authors assume that these glands are mainly associated with reproduction and demarcation of territory. The structure of precloacal glands in Amphisbaena alba was previously studied by Antoniazzi et al. (Zoomorphology 113:199-203, 1993; J. Morphol. 221:101-109, 1994). These authors suggested that as the animal moves inside tunnels, the secretion plugs are abraded against the substrate, releasing a secretion trail. Some aspects of the plug were difficult to interpret in fine sections due to the dense and brittle nature of the plug. The morphology of the trail, and the manner of deposition on the substrate, have never been reported. This study presents a primarily scanning electron microscopic description of A. alba precloacal glands and of the secretion plugs. It also demonstrates experimentally the formation of the trail and its fine morphology. The results show that when the plugs scrape against the substrate, their constitution helps them to fragment into tiny pieces, which are spread on the ground, thus forming a trail. Each one of the fragments corresponds to a secretion granule of the precloacal gland's secretory cells. In this way, the trail might have an extensive area for volatilization of semiochemicals, constituting an efficient means of intraspecific communication inside the tunnels.

Apocrine sweat glands in the circumanal glands of the dog

Apocrine sweat glands in the circumanal glands of the dog are not connected morphologically with the lobules of the circumanal glands. However, an apparent functional association has been demonstrated and it is possible that the apocrine sweat glands might serve as excretory ducts for degenerated polyhedral cells of the circumanal glands. In this study, we examined the ultrastructure of the apocrine sweat glands in the circumanal glands of the dog in an effort to define more precisely the relationship between the apocrine sweat glands and the circumanal glands. Paraffin sections stained with azan and sections after immunohistochemical staining with antibodies against actin were examined by light microscopy. Samples fixed by aldehyde perfusion were examined with the electron microscope. Diameters of apocrine sweat glands and height of cells in the secretory epithelium varied considerably. Immunohistochemical staining for actin was weakly positive in the supranuclear regions of secretory cells and very intense in myoepithelial cells. In secretory cells, the endoplasmic reticulum was well-developed. Multivesicular bodies were abundant and were discharged into lumens. Apocrine secretion and exocytosis were observed at luminal surfaces of secretory cells. There were three types of large granule in the cytoplasm: giant mitochondria without cristae; membrane-enclosed globules with or without myelin-like contents; and electron-dense, homogeneous, globular structures. Luminal surfaces were always covered with microvilli, and extensive folding of the cell membrane was found in basal regions. Bundles of actin filaments were dispersed throughout the cytoplasm. In the lumens of apocrine tubules, we observed shed secretory cells with well-preserved normal fine structures. We also noted the differentiation of secretory cells that was due to cell renewal. Apocrine sweat glands in the circumanal glands of the dog appear to be more active than those on the general body surface in terms of apocrine secretion, exocytosis, and the release of multivesicular bodies. Shed secretory cells containing large granules, as well as degenerated polyhedral cells from the circumanal glands, might contribute, to some extent, to the subtle composition of sweat from these apocrine sweat glands.

Circumanal glands of the dog: a new classification and cell degeneration

BACKGROUND

The circumanal glands of the dog are thought to be a glandular tissue, but there is some controversy as to whether they should be classified as exocrine or endocrine. In this study, we examined the nature of the circumanal glands to determine whether they should be described as exocrine, endocrine, or something else altogether. In addition, we investigated the cell degeneration in lobules of the circumanal glands in relation to the apocrine glands.

METHODS

Light microscopic observations were made of paraffin sections stained with hematoxylin and eosin, and after immunohistochemical staining with antibodies against alpha-smooth muscle actin, keratin, filaggrin, and 3beta-hydroxysteroid dehydrogenase/isomerase (3beta-HSD). Samples were also examined by electron microscopy after fixation by aldehyde perfusion.

RESULTS

The lobules of circumanal glands could be divided into two types on the basis of the presence or absence of cysts. Four layers (I-IV) were detected in the lobules with cysts. The outermost layer (layer I or the basal layer) consisted of flattened cells that contained bundles of tonofilaments and were stained immunohistochemically with the antibody against keratin. Layer II (the polyhedral or "spinous" layer) consisted of polyhedral cells that contained bundles of tonofilaments. These cells were connected to adjacent cells by desmosomes, interdigitations, and gap junctions, and they were immunopositive for keratin. A small number of polyhedral cells were immunopositive for 3beta-HSD. Layer III (the granular layer) was composed of flattened cells that contained hematoxylin-stainable granules and were moderately immunopositive for filaggrin. The innermost layer (layer IV or the horny layer) consisted of keratin. Lobules without cysts consisted only of layer I (the basal layer) and layer II (the polyhedral layer). Lobules of the circumanal glands were not directly connected to apocrine glands. Polyhedral cells degenerated and were phagocytosed by basal cells at a periphery of lobules. Then, basal cells phagocytosing degenerated polyhedral cells escaped from lobules, moved into the walls of apocrine glands, and, finally, dropped into the lumen of apocrine glands.

CONCLUSIONS

Lobules of the circumanal glands have many characteristics of epidermis (a basal layer, a polyhedral or "spinous layer," a granular layer, and a horny layer) and they should not be classified as glandular tissue. The cysts in lobules can be interpreted as "closed hair canals." We suggest that steroid metabolism might occur in the polyhedral cells of the lobules.

[The caudal gland in the cat is a hepatoid gland]

The cat supracaudal gland is usually considered as a conglomeration of massive sebaceous glands, although the author of the only detailed description of its structure stated that it is a hepatoid gland (HG) of lower order. Investigation of the supracaudal gland in adult cats of both sexes showed that it is a massive layer of HGs opening either into dilated follicles of coarse hairs or into large cisterns. These glands possess all features specific for HGs: polyhedral cells, a network of intracellular canaliculi, abundant cytoplasmic protein granules, release of protein structures from the cells to adjacent canaliculi. The reasons for misinterpreting certain structural properties are discussed. It was shown that the cat caudal gland is a typical "embryonal" HG previously described in dogs and certain hollow-horned ruminants. They secrete protein and hydrophobic lipids, have wide excretory ducts, are connected with coarse hairs, are devoid of cysts, and have no sexual dimorphism. Formation of cisterns, special secretion receptacles of the cat supracaudal gland, was monitored. It begins with stagnation of the lipid-protein secretion in the hair follicle and progresses until transformation of the whole glandular lobe to the cistern and dissolving of the hair shaft in it.

[The sex dimorphism of the hepatoid circumanal glands in the dog and the dynamics of its development]

The histology of sexual dimorphism of the dog hepatoid circumanal glands has not been studied before. Studies of hepatoid and other skin glands of the circumanal region of adult dogs and puppies (1 and 38 days) of both sexes have shown striking differences in the structure of this region in adult males and females and complete qualitative similarity in puppies of the both sexes. The hepatoid glands of adult males form a massive glandular layer comprising 91% of the skin thickness and supplanting all other glandular types. In adult females these glands are reduced to widely spaced islets (12% of the skin thickness), and the apocrine glands are the prevailing glandular type (53%). The hepatoid glands of puppies of the both sexes develop according to the same structural scheme, approaching rapidly to the glands of adult males. In female puppies they develop more rapidly, and at the age of 38 days their absolute size (length of glandular lobes) is already thrice that of adult females. The hepatoid glands of adult females undergo a very significant regress and possess several structural features suggesting their degeneration.

[Histological variants of the hepatoid glands in representative Canidae and Cavicornia: the structural and histochemical characteristics]

Both the original material and the data from literature collected in two previous papers, show a considerable diversity of structure and secretion of the glands which constitute the hepatoid gland type. According to the body of available histological (including morphometrical) and histochemical data, the authors distinguish: a) features characteristic of the hepatoid gland type only which do not appear in other types of skin glands; b) seven histological varieties within the hepatoid gland type. These seven varieties can be united, according to the laws of their structure and function, into two groups (1-3 and 5-7), with an intermediate variety (4) between them. The first group includes hepatoid glands of the "classical" structure which has been previously detaily exampled by circumanal glands of the dog: these glands possess cysts, produce a purely protein secretion; the secretion type is merocrine. The second group comprises mero-holocrine hepatoid glands which are characterized by the absence of cysts, broader excretion ducts, and a capability to produce, besides protein, considerable amounts of melanin and/or hydrophobic lipids.

[The histological and histochemical characteristics of the hepatoid circumanal glands in the dog: the features of similarity and difference with the skin glands of other types]

Three types of skin glands, the derivatives of the outer root sheath of the hair follicle, have been compared, which are represented by hepatoid, sebaceous and apocrine sweat glands. There are three characteristic properties inherent to hepatoid glands, existence of a network of intercellular secretory tubules, lysis of some secretory cells during the duct formation which is not the fatty transformation and cyst formation.

Correlation of Propionibacterium acnes populations with the presence of triglycerides on nonhuman skin

The skins of mice, rats, rabbits, sheep, guinea pigs, and dogs were cultured for Propionibacterium acnes. Only the sebaceous regions (perianal gland) of guinea pigs harbored a significant P. acnes population. Analysis of the lipid from this region revealed a significant percentage of triglycerides, compounds lacking in the sebum of the other animals.

C19-Steroid metabolism by canine prostate, epididymis and perianal glands. Application of the twin-ion technique of gas chromatography/mass spectrometry to establish 7 alpha-hydroxylation

The present study applied the twin-ion technique of gas chromatography/mass spectrometry to establish 7 alpha-hydroxylation of 5 alpha-androstane-3 beta, 17 beta-diol by canine prostate, epididymis and perianal glands. 5 alpha-[4-14C, 7 beta-2H0.52]Androstane-3 beta, 17 beta-diol (0.5 microM) was incubated for 60 min at 37 degrees C with minced canine prostate and epididymis in 50 ml 0.067 M phosphate buffer (pH 7.4) containing NADPH (0.2 mM). The principal radioactive metabolite fraction was isopolar in thin-layer chromatography with 5 alpha-androstane-3 beta, 7 alpha, 17 beta-triol and contained 24% (prostate incubation) and 23% (epididymis incubation) of the radioactivity added. Following gas chromatography of the trimethylsilyl ether derivative of these metabolites, the peak with the retention time of the derivative of 5 alpha-androstane-3 beta, 7 alpah, 17 beta-triol yielded a mass spectrum consistent with that of the authentic standard triol and gave the characteristic twin-ion, though with some loss of deuterium. Incubation of 5 alpha-[4-14C, 7 beta-2H0.46]dihydrotestosterone (7 microM) and minced canine perianal glands and NADPH (0.2 mM) gave in 5% yield a transformation product with an RF-value of 5 alpha-androstane-3 beta, 7 alpha, 17 beta-triol. One half of the chromatographic fraction was subjected to gas chromatography/mass spectrometry as the free steroid, the other as the CrO3-oxidation product. The site of hydroxylation was identified as 7 alpha from the gas chromatography retention time of the free 7 beta-deuterated (twin-ion) triol and mass-spectrometry loss of deuterium in the 3,7,17-trione produced by mild CrO3 oxidation. Results of a comparative study of the metabolism of [4-14C]testosterone and 5 alpha-dihydro[4-14C]-testosterone with minced canine perianal glands and shoulder skin showed that, whereas both tissues contain a high level of 3 beta-hydroxysteroid oxidoreductase, only the perianal glands were able to transform radioactive testosterone to the 5 alpha-reduced derivatives and thence to the 7 alpha-hydroxylated product.

Pathology of the anal glands with special reference to their mucin histochemistry

The anal gland pathology comprises cystic anal glands (so-called anal gland cyst hamartomas), anal gland carcinomas, and anal fistulas with or without carcinoma. The differential diagnosis of these conditions from other cysts and carcinomas of the anal region can be difficult. The authors have therefore compared conventional history with mucin histochemistry in normal and pathological anal glands. In contrast to normal rectal mucosa the mucus of anal glands was characterized by strong PAS-reactivity that was completely abolished after periodate borohydride saponification indicating scarcity of absence of O-acylated sialic acids in the anal gland mucus. A pattern similar to this was found in one of two tumours classified histologically as anal gland carcinomas, in four of eight colloid carcinomas arising in preexisting fistulas, and in two cases of mucoepidermoid carcinoma of the anal region. The results indicate that the method in some cases may be of value in differentiating between carcinomas arising in anal gland epithelium and in rectal mucosa. The cystic anal glands showed decreased secretion but no qualitative histochemical differences from anal glands. On the basis of the patients' histories it is suggested that the so-called anal gland cyst hamartoma at least in some cases could be an inclusion cyst of anal glands on the inflammatory basis.

Tissue-steroid interactions in canine hormone-dependent tumours

Mammary tumour tissue from two bitches and an anal adenoma from a dog were investigated for steroid receptor interaction. Both mammary tumours possessed cytoplasmic macromolecules sedimenting with coefficients of 4S and 8S that bound oestradiol-17beta. These receptors had molecular weights of approximately 60,000 and 180,000 respectively. Transfer of the oestrogen to the nucleus was shown and the presence of a 4-5S nuclear protein demonstrated. The anal adenoma had a cytoplasmic receptor, with a sedimentation value in a sucrose density gradient of 4-5S with respect to bovine serum albumin, that bound tritiated 5alpha-androstane-3alpha, 17alpha-diol. No affinity could be demonstrated for other C19-steroids examined. The significance of these findings in terms of the hormone dependence of the tumours investigated and the possible development of these studies to promote rational therapy in such cases is discussed.

Gyrinidal: a sesquiterpenoid aldehyde from the defensive glands of gyrinid beetles

Three species of gyrinid beetles (Gyrinus ventralis, Dineutes hornii, and D. serrulatus) have been found to produce the nor-sesquiterpenoid aldehyde gyrinidal in the secretion of their pygidial defensive glands. This highly functionalized terpene is shown to be (E,E,E)-3,7-dimethyl-8,11-dioxo-2,6,9-dodecatrienal on the basis of spectral evidence and chemical degradation. While a very wide range of sesquiterpenoid structures occur in nature, gyrinidal appears to be the most highly oxidized acyclic sesquiterpene known.

From frog skin to sheep rumen: a survey of transport of salts and water across multicellular structures

All higher animals, whether they live in water or on dry land, are faced with the necessity of regulating rather closely their intake and excretion of salts and water in order to maintain the constancy of their internal ionic environment. The kidney is in general the most important organ of the body as far as the excretion of sodium, potassium, chloride and water is concerned, but there are other tissues which also play a part in controlling the ionic balance between the internal and external environments, such as the intestinal mucosa, the skin and urinary bladder in amphibia, the gill epithelium in fishes, the salt gland in marine birds, and the epithelium of the rumen in ruminants. In addition to excretory and absorptive organs of this type, there are others which are secretory and whose function involves the production of fluids differing in ionic composition from the blood plasma. Examples include the glands which secrete saliva and sweat, the oxyntic acid-producing cells of the gastric mucosa, and the epithelium of the stria vascularis which generates the potassium-rich endolymph of the mammalian cochlea. The purpose of this article is to consider briefly what is known about the active transport of salts and water across some typical multicellular secretory tissues, and to attempt in the process to discern what properties they have in common and in what respects they are specialized.