Ultrastructure and immunohistochemical characterization of proteins concerned with the secretory machinery in goat ceruminous glands.

The expression of soluble N-ethyl-maleimide sensitive fusion attachment protein receptor (SNARE) proteins in apocrine glands has not been fully elucidated. In addition to performing ultrastructural observation of the ceruminous glands in goats, our study focuses on the demonstration of ß-defensins, SNARE proteins and Rab3D in these glands with the use of immunohistochemical methods. The secretory cells were equipped with two types of vesicles, Golgi apparatus and abundant rough endoplasmic reticulum (ER). Additionally, in some of them, the characteristic concentric structures composed of rough ER were observed in their circum- and infranuclear parts. The expression of phosphorylated inositol requiring enzyme 1a was also detected. These findings may indicate their ability to produce numerous secretory proteins and the maintenance of homeostasis in the glandular cells. Furthermore, ß-defensins were demonstrated as products of the ceruminous glands. The present investigation also revealed the presence of SNARE proteins and Rab3D. It is suggested that these proteins are concerned with the secretory machinery of this gland type.

Ciclooxygenase inhibitor and metronomic chemotherapy association for the treatment of metastatic anal sac carcinoma in dog: case report / Inibidor de ciclo-oxigenase associado à quimioterapia metronômica no tratamento de carcinoma de saco anal metastático canino: relato de caso

Metronomic chemotherapy consists of an anticancer modality treatment. It is applicable in patients at an advanced stage, with the objective of increasing overall survival. The aim of this study was to report an anal sac apocrine carcinoma case in a dog with lymph node metastasis treated with metronomic chemotherapy sequential to surgery and conventional chemotherapy using gemcitabine and carboplatin. Metronomic chemotherapy was associated with cyclooxygenase-2 (COX-2) inhibitors, due to strong tumor COX-2 immunohistochemistry expression. Metronomic chemotherapy was initiated with cyclophosphamide, but it was replaced by lomustine, also in metronomic dosage, due to adverse effects. Treatment showed effectiveness, since the patient's overall survival exceeded 1095 days (36 months), considerably higher than the mean overall survival expected for this pathology.(AU)

Quimioterapia metronômica consiste em uma modalidade de tratamento anticancerígeno, aplicável a pacientes em estadiamento avançado, com o objetivo de aumentar a sobrevida global. O objetivo deste trabalho foi relatar um caso de carcinoma apócrino do saco anal, em uma cadela, com metástase em linfonodo tratado com quimioterapia metronômica sequencial à cirurgia e quimioterapia convencional utilizando-se gencitabina e carboplatina. O tratamento metronômico foi associado ao uso de inibidores de ciclo-oxigenase-2 (COX-2), baseando-se na constatação de sua expressão tumoral. A terapia metronômica iniciou-se com ciclofosfamida, mas houve necessidade de substituição pela lomustina, também em dose metronômica, devido à ocorrência de efeitos adversos. O tratamento mostrou ser eficaz, pois a sobrevida do paciente ultrapassa 1095 dias (36 meses) desde a cirurgia, sendo consideravelmente maior que a média relatada para essa patologia.(AU)

Ultrastructural characteristics of the caeca of basal polyopisthocotylean monogeneans of the families Chimaericolidae and Hexabothriidae parasitic on cartilaginous fishes.

Ultrastructural differences are shown between the caecal organization in three blood-feeding polyopisthocotylean monogeneans, i.e., the chimaericolid Chimaericola leptogaster from the holocephalan Chimaera monstrosa and two hexabothriids, Callorhynchocotyle callorhynchi from the holocephalan Callorhynchus capensis and Rajonchocotyle emarginata from the elasmobranch Amblyraja radiata. In C. leptogaster, digestive cells and connecting syncytium, joined close to the luminal surface by septate junctions, are arranged alternately along the caecal epithelial wall; the nuclear regions of both cell types are sunk below the general level of the caecal epithelium; a concave depression on the apical margin of the digestive cells bears lamellae; and this depression is covered by a lamellate bubble formed by thin projections emanating from the connecting syncytium. The luminal surface of the connecting syncytium is covered with outgrowths terminating in the form of long, narrow processes. In R. emarginata and C. callorhynchi, the predominant digestive cells are at different stages of development and occur in groups, developing digestive cells bulge into the caecal lumen from the connecting syncytium with contact sites present close to the luminal surface, and the luminal surface structures of both the connecting syncytium and the digestive cells are short lamellae. In these two hexabothriids, a holocrine (or apocrine) process for the elimination of digestive product is assumed via the detachment of fully differentiated, bulging digestive cells. Free, apparently sloughed digestive cells and residual bodies are present within the caecal lumen, and replacement digestive cells are numerous in the connecting syncytium. In the chimaericolid, free bubbles containing residual bodies and portions of digestive cells filled with degenerating digestive vesicles occur in the caecal lumen along with large amounts of male and female reproductive material. The usefulness of characteristics of the caecal ultrastructure as taxonomic traits at the family level is discussed.

Apocrine secretion in Drosophila salivary glands: subcellular origin, dynamics, and identification of secretory proteins.

In contrast to the well defined mechanism of merocrine exocytosis, the mechanism of apocrine secretion, which was first described over 180 years ago, remains relatively uncharacterized. We identified apocrine secretory activity in the late prepupal salivary glands of Drosophila melanogaster just prior to the execution of programmed cell death (PCD). The excellent genetic tools available in Drosophila provide an opportunity to dissect for the first time the molecular and mechanistic aspects of this process. A prerequisite for such an analysis is to have pivotal immunohistochemical, ultrastructural, biochemical and proteomic data that fully characterize the process. Here we present data showing that the Drosophila salivary glands release all kinds of cellular proteins by an apocrine mechanism including cytoskeletal, cytosolic, mitochondrial, nuclear and nucleolar components. Surprisingly, the apocrine release of these proteins displays a temporal pattern with the sequential release of some proteins (e.g. transcription factor BR-C, tumor suppressor p127, cytoskeletal ß-tubulin, non-muscle myosin) earlier than others (e.g. filamentous actin, nuclear lamin, mitochondrial pyruvate dehydrogenase). Although the apocrine release of proteins takes place just prior to the execution of an apoptotic program, the nuclear DNA is never released. Western blotting indicates that the secreted proteins remain undegraded in the lumen. Following apocrine secretion, the salivary gland cells remain quite vital, as they retain highly active transcriptional and protein synthetic activity.

Functional ultrastructure of the hexacanth larvae in the bothriocephalidean cestode Eubothrium salvelini (Schrank, 1790) and its phylogenetic implications.

Functional ultrastructure and its phylogenic implications in the bothriocephalid cestode Eubothrium salvelini (Schrank, 1790) are described and discussed. The infective hexacanth shows bilateral symmetry in cellular organization. The mature hexacanth is armed with three pairs of oncospheral hooks of a heterogeneous electron density. It is covered by a thin layer of the oncospheral tegument, possessing characteristic bubble-like processes at the surface. Within the infective hexacanth larva five cell types were distinguished: (1) a binucleated subtegumental cell; (2) the U-shaped, tetranucleated penetration gland; (3) two nerve cells; (4) three types of somatic cells represented by: i) myocytons of both somatic and hook musculature, ii) numerous degenerating micromeres with pycnotic nuclei and iii) a new oncospheral cell type, the interstitial cell, that has never been observed in any other hexacanth; and (5) large germinative cells with characteristic prominent nucleoli in their large spherical nuclei. Functions of all the cell types are described on the basis of the obtained ultrastructural characteristics and previously published reports. The mode of the penetration gland secretion is classified as apocrine. Flame cells have never been observed within the hexacanth of E. salvelini. The results of the present study, comparing the functional aspects of the ultrastructure of the hexacanths of E. salvelini with literature data on the oncospheres of other bothriocephallideans and diphyllobothriideans, suggest potential phylogenetic and evolutionary criteria for determining relationships among these groups of tapeworms.

Functional morphological characteristics of the interdigital sinus in the sheep.

The present paper describes two distinct morphological features of ovine interdigital sinus, which were examined by means of scanning electron microscopy. In the sweat glandular component, acini with epithelial cells exhibiting a paved appearance and apocrine secretion were observed. In the same gland, other acini with cells exhibiting different luminal surfaces and simultaneous apocrine and merocrine secretion were recorded. The numerous hairs embedded within the waxy material of the sinus exhibited two types. The first type, with a round profile, had a special leaflet structure on the tip, whereas the second type had a convex profile. The comparative differences and probable functional relations of these integumentary structures are discussed. The mixed picture of the epithelial cells of the sweat glands suggests the release of different products. The hair microstructure correlated with the mechanism of hold and release of the secretory material of the interdigital sinus.

Immunocytochemical localization of lysozyme and beta-defensin in the apocrine glands of the equine scrotum.

The present study revealed in detail the subcellular localization of lysozyme and beta-defensin in the apocrine glands of the equine scrotal skin, a specific body region. The apocrine glandular cells were equipped with a varying number of secretory granules, a well-developed Golgi apparatus and abundant cisternae of the rough endoplasmic reticulum within their cytoplasm. In these cells, reactive gold particles representing lysozyme were detectable in the secretory granules as well as the Golgi apparatus and elements of the rough endoplasmic reticulum. Additionally, the antimicrobial peptide group of beta-defensin was also localized in the above-mentioned ultrastructures of the secretory cells. The presence and secretion of such substances that may serve as a non-specific defense against microorganisms are suggestive of the protective effect of the secretory production elaborated by the apocrine glands.

Scanning electron microscopic features of the ovine interdigital sinus.

This article describes the scanning electron microscopic (SEM) features of the ovine interdigital sinus. The lumen was filled with a dense secretory material and quite a number of hairs embedded in the luminal content. For SEM purposes, the sinus was divided into three parts: base, body and neck. At the cut surface, the wall exhibited significant folds which were almost absent in the base, the very short blind end of the sinus. The wall had three layers: epidermis, dermis and fibrous capsule. Stratified epithelium with a prominent keratin layer faced the lumen. The inner surface was similar to the skin surface; however, it was coarser due to folds. The fibrous capsule was composed mainly of dense connective tissue, constituting the outermost layer of the wall. The dermis contained common skin structures including sebaceous glands, hair follicles, arrector pili muscles and apocrine glands. Sebaceous glands appeared as groups of bubbles if they were not collapsed. Apocrine glands generally appeared as a group of coiled tubules. They frequently exhibited apocrine blebs, which is a feature of apocrine secretion. SEM was able to locate some secretory vesicles in the lumen of apocrine tubules which is frequently filled by secretory content. Thus, the apocrine tubules exhibited classical features of apocrine secretion.

Morphology of the intermandibular gland of the Lesser mouse deer, Tragulus javanicus.

The morphology of the intermandibular gland of the Lesser mouse deer (Tragulus javanicus), which plays an important function in marking area and territory and in the reproductive behaviour of the animal, was examined using immunohistochemistry, lectin histochemistry and scanning electron microscopy. The gland was composed of sebaceous and apocrine glandular material. Sebaceous glands occupied a greater area of the total gland and consisted of many large lobules with polyhedral cells having a pale cytoplasm. The sebaceous gland, being holocrine, possessed no special secretory ducts. The apocrine gland was lined by cuboid cells and the secretory products were often seen in the apical portions of the cells. Myoepithelial cells contained actin filaments lining the basal membranes of the apocrine gland and were surrounded by nerve fibres which immunostained with protein gene product 9.5. The secretion of the gland appears to be a mixture of larger amounts of lipid material from sebaceous glands, and glycoconjugates secreted by both sebaceous and apocrine glands. Lectin histochemistry detected these as galactose, N-acetyl-D-galactosamine, N-acetyl-D-glucosamine, D-mannose and D-glucose. The male gland was larger in size and contained more N-acetyl galactosamine and N-acetyl glucosamine in its secretion than the gland of the female. This implied the presence of sexual differences in secretions in the intermandibular gland of the Lesser mouse deer.

Human ceruminous gland: ultrastructure and histochemical analysis of antimicrobial and cytoskeletal components.

The ceruminous glands in the skin of the human external auditory canal are modified apocrine glands, which, together with sebaceous glands, produce the cerumen, the ear wax. Cerumen plays an important role in the protection of the ear canal against physical damage and microbial invasion. We studied the morphology of the glandular cells by light and electronmicroscopy. Antimicrobial and cytoskeletal components of the ceruminous glands were investigated by immunohistochemical methods. Numerous antimicrobial proteins and peptides are present in the ceruminous glandular cells: beta-defensin-1, beta-defensin-2, cathelicidin, lysozyme, lactoferrin, MUC1, secretory component of IgA. These data indicate a crucial role in the innate host defense against diverse pathogens. The apocrine secretion mechanism is a special mode of secretion by which the apical part of the cell cytoplasm surrounded by a membrane is pinched off. We could show that the presence of actin filaments, CK 19 and CK 7, seems to play a role in the pinching-off mechanism. Finally, we showed the secretion of lipid vesicles from the ceruminous gland. We could extend the number of detected antimicrobial peptides and proteins in human ceruminous glandular cells that protect the surface of the external auditory meatus. In addition, we detected proteins involved in the apocrine secretion mode of the ceruminous gland.

Cytochemical characterization of glycoconjugates in the apocrine glands of the equine scrotal skin.

Cytochemistry of glycoconjugates in the apocrine glands in the scrotal skin of the horse was studied using cytochemical methods for electron microscopy, particularly lectin cytochemistry. The secretory cells possessed a variable number of secretory vesicles, a well-developed Golgi apparatus, and abundant cisternae of the rough endoplasmic reticulum. Additionally, the basolateral plasma membrane formed numerous interdigitating folds. Glycoconjugates with vicinal diol groupings were present predominantly in the secretory vesicles, the Golgi apparatus, the surface coat of the plasma membrane, and the majority of the intracellular membranes. With lectin cytochemistry, the secretory vesicles of the glandular cells exhibited glycoproteins with different terminal sugars (alpha-D-mannose, beta-D-galactose beta-N-acetyl-D-glucosamine, and sialic acid). Several sugars were distinctly prominent in the surface coat of the plasma membrane of the secretory cells. The cytochemical properties of the complex glycoconjugates found are discussed in relation to the specific functions of the glandular secretions. These glands may have an important role in not only thermoregulation but protection of the scrotal skin, a specific body region.

Immunohistochemical detection of macrophage migration inhibitory factor in fetal and adult bovine epididymis: release by the apocrine secretion mode?

Originally defined as a lymphokine inhibiting the random migration of macrophages, the macrophage migration inhibitory factor (MIF) is an important mediator of the host response to infection. Beyond its function as a classical cytokine, MIF is currently portrayed as a multifunctional protein with growth-regulating properties present in organ systems beyond immune cells. In previous studies, we detected substantial amounts of MIF in the rat epididymis and epididymal spermatozoa, where it appears to play a role during post-testicular sperm maturation and the acquisition of fertilization ability. To explore its presence in other species not yet examined in this respect, we extended the range of studies to the bull. Using a polyclonal antibody raised against MIF purified from bovine eye lenses, we detected MIF in the epithelium of the adult bovine epididymis with the basal cells representing a prominently stained cell type. A distinct accumulation of MIF at the apical cell pole of the epithelial cells and in membranous vesicles localized in the lumen of the epididymal duct was obvious. In the fetal bovine epididymis, we also detected MIF in the epithelium, whereas MIF accumulation was evident at the apical cell surface and in apical protrusions. By immunoelectron microscopy of the adult bovine epididymis, we localized MIF in apical protrusions of the epithelial cells and in luminal membrane-bound vesicles that were found in close proximity to sperm cells. Although the precise origin of the MIF-containing vesicles remains to be delineated, our morphological observations support the hypothesis that they become detached from the apical surface of the epididymal epithelial cells. Additionally, an association of MIF with the outer dense fibers of luminal spermatozoa was demonstrated. Data obtained in this study suggest MIF release by an apocrine secretion mode in the bovine epididymis. Furthermore, MIF localized in the basal cells of the epithelium and in the connective tissue could be responsible for regulating the migration of macrophages in order to avoid contact of immune cells with spermatozoa that carry a wide range of potent antigens.

Ultrastructural analysis of the integument of a desert-adapted mammal, the one-humped camel (Camelus dromedarius).

In this study, we conducted a light microscopic and ultrastructural analysis of the integument of the one-humped camel (Camelus dromedarius). In general, the epidermal strata of the camel integument appeared typical of those found in non-desert mammals. Two cell populations were noted in the stratum basale: one with a flat, non-serrated base and the other with a highly serrated base. Typical fine structure was observed in keratinocytes of the stratum spinosum and stratum granulosum. The stratum corneum was six to 10 cells thick. Within the different strata, overall cell morphologies and the general distribution and relative abundance of cellular organelles appeared typical. Dermal features included the presence of myoepithelial cells surrounding apocrine tubular glands. Inter- or intracellular canaliculi within the secretory cells of the apocrine glands, reported to be present in certain other non-desert mammals, were not evident in the camel. Together, these data indicate that while the camel is clearly adapted for a desert lifestyle, these adaptations do not include significant specializations at the cellular or subcellular level in the integument.

Both type-I hemidesmosomes and adherens-type junctions contribute to the cell-substratum adhesion system in myoepithelial cells.

Myoepithelial cells present in exocrine glands cause secretion from the glands by contraction. They have mixed characteristics with regard to cytoskeletal elements, containing both epithelial-type intermediate filaments and smooth muscle-type myofilaments. For further characterization, myoepithelial cells from bovine apocrine sweat glands and tracheal glands were here examined with special attention to the cell-substratum adhesion system. Immunofluorescence microscopy using a panel of antibodies against adherens-type junctional and hemidesmosomal proteins demonstrated two types of cell-substratum junctions in myoepithelial cells from both glands. Type-I hemidesmosomes (HDs) consisting of plectin, BP230, integrin alpha6beta4, and BP180 were thus observed as punctate arrays longitudinally arranged along myoepithelial cell surfaces, while adherens-type junctions were similarly evident as linear rib-like structures. Double-label immunofluoresence revealed the two junctions to be distributed in a mutually exclusive or independent manner. Electron microscopy further demonstrated that apocrine myoepithelial cells surround secretory epithelial cells completely, without any gaps, HDs being abundant along the basement membrane, but with no distinct structures in the inter-hemidesmosomal regions. Immunoelectron microscopy, however, revealed an interhemidesmosomal localization of vinculin, pointing to the existence of adherens-type junctions. Secretory epithelial cells in tracheal glands were found not to be completely covered with myoepithelial cells, so that more than half of them are directly attached to the basement membrane, where they form type II-HDs lacking BP230 and BP180, but no detectable adherens junctions, like epidermal basal cells and sebaceous gland cells. These observations demonstrate that, in addition to their cytoskeleton, myoepithelial cells have both epithelial- and smooth muscle-type cell-substratum adhesion structures, i.e. HDs and dense plaque-like adherens junctions.

Apocrine glands in the eyelid of primates contribute to the ocular host defense.

Apocrine glands of Moll are regular components of primate eyelids. We studied the distribution and localization of these glands in three different primate species, the common marmoset, the rhesus monkey, and the hamadryas baboon. In addition, we tested the primate glands of Moll with antibodies against antimicrobial proteins, cytoskeletal proteins and the androgen receptor. The glands of Moll differ in abundance and distribution in different monkeys. In the common marmoset, a representative of the New World monkeys, Platyrrhini, the apocrine glands are frequently found at the lid margin and in the overlying epidermis of the lid. In the rhesus monkey and the hamadryas baboon, representatives of Old World monkeys, Catarrhini, apocrine glands are rarer and located predominantly at the margin of the lid. The immunohistochemical analysis indicates the presence of a variety of antimicrobial proteins, e.g. lysozyme, beta-defensin-2, adrenomedullin, lactoferrin, and IgA, in these glands. Interestingly, there are basically no androgen receptors in the nuclei of apocrine glands at the lid margin in all three monkey species. In the common marmoset, however, androgen receptors are found in apocrine glands of the overlying epidermis of the lid. We speculate that the glands of Moll are derived from apocrine glands as found in the skin of the entire body in New World monkeys which developed at the lid margins of higher primates and humans into specialized glands secreting agents of host defense in the eye.

Histochemistry of complex carbohydrates in the ceruminous glands of the goat.

The localization and chemical nature of complex carbohydrates in the ceruminous glands of the Japanese miniature (Shiba) goat were studied using light and electron microscopic histochemical methods, particularly lectin histochemistry. The epithelial cells and luminal secretion of the caprine ceruminous glands contained large amounts of neutral and smaller amounts of acidic glycoconjugates with different terminal sugars (alpha- d-mannose, alpha-L-fucose, alpha-N-acetyl-D-galactosamine, beta-D-galactose, beta-N-acetyl-D-glucosamine, and N-acetyl-neuraminic acid). Several sugars (alpha-L-fucose, beta-D-galactose, beta-N-acetyl-D-glucosamine, and N-acetyl-neuraminic acid) were also detectable in the secretion of the sebaceous glands. The results obtained are discussed with regard to the specific function of the glandular secretion mixture. The complex glycoconjugates found in the ceruminous gland secretion may control viscoelasticity of and bacterial proliferation within the cerumen in order to protect the external auditory canal against physical damage or microbial attacks.

Human glands of Moll: histochemical and ultrastructural characterization of the glands of Moll in the human eyelid.

The function of the human gland of Moll of the eyelid is not exactly known. We studied the secretory and cytoskeletal components of these apocrine glands in males and females by immunohistochemical methods, and the ultrastructural organization of the glandular cells with an electron microscope. The glands of Moll are exclusively located at the margin of the eyelids and their ducts empty into the lash follicle. Immunohistochemical staining for actin and cytokeratins CK19 and CK7 points to the involvement of actin in the pinching-off mechanism of the apical cell protrusion during apocrine secretion and to a stabilizing role for the cytokeratins in this apical region of the glandular cells. The presence of the bacteriolytic enzyme lysozyme, the membrane-associated mucin 1, and the immunoglobulin A and its secretory component within the gland suggest a function in local immune defense. The presence of a variety of sugar components in the secretory product was verified by lectin histochemistry and periodic acid Schiff and Alcian blue stain. We suppose that these apocrine glands are active from birth in producing agents against pathogenic microorganisms in the eyelid shaft and on the ocular surface.

Histochemical analysis of glycoconjugates in the ceruminous glands of the North American raccoon (Procyon lotor).

The distribution and selectivities of glycoconjugates in the ceruminous glands of the North American raccoon (Procyon lotor) were studied by light and electron microscopic histochemical methods, particularly lectin histochemistry. In the modified apocrine glands present, the apocrine secretion mode was combined with exocytosis, whereby the secretory epithelium and the luminal secretion of the ceruminous glands exhibited considerable amounts of complex carbohydrates with various terminal sugars (alpha-D-mannose, beta-D-galactose, alpha-L-fucose, alpha-N-acetyl-galactosamine, beta-N-acetyl-D-glucosamine, N-acetyl-neuraminic acid). Alpha-L-fucose and N-acetyl-neuraminic acid were distinctly prominent in secretory granules or within the free surface coat of the plasma membrane of the glandular cells, as well as in the luminal secretion. Several free sugars (alpha-D-mannose, alpha-L-fucose, beta-D-galactose, beta-N-acetyl-D-glucosamine) were also detectable in the secretion of associated sebaceous glands. The ceruminous gland secretion may control viscoelasticity and/or bacterial degradation of the glandular secretion mixture to improve the protection of the external auditory canal against physical damage or microbial contamination.

Apocrine secretory mechanism: recent findings and unresolved problems.

Cell secretion is an important physiological process that ensures smooth metabolic activities, tissue repair and growth and immunological functions in the body. It occurs when the intracellular secretory materials are released to the exterior; these may be in the form of lipids, protein or mucous and may travel through a duct system or via blood to reach the target organ. To date three types of secretory mechanisms have been characterized, they include apocrine, holocrine and exocytosis. Apocrine secretion occurs when the release of secretory materials is accompanied with loss of part of cytoplasm. The secretory materials may be contained in the secretory vesicles or dissolved in the cytoplasm that is lost during secretion. In holocrine secretion, the entire cell is secreted into the glandular lumen, and it is presumed that the intended secretory materials are contained in the cell cytoplasm. Exocytosis is the most commonly occurring type of secretion; here the secretory materials are contained in the secretory vesicles and released without loss of cytoplasm. Apocrine secretory mechanisms have not been properly discussed; for example the biochemical and physiological pathways that regulate apocrine secretory process are not clearly known. Similarly, the plasma membrane dynamics during apocrine secretion has not been researched. In other glands morphological features during apocrine secretion have not been documented. The current paper reviews what is known about apocrine secretion, recent findings and highlights on the unresolved areas for future research.

PACAP activated adenylate cyclase in human sweat glands. An ultracytochemical study.

The ultracytochemical localization of adenylate cyclase (AC) was studied after stimulation with pituitary adenylate cyclase activating peptide (PACAP) in human sweat glands. PACAP stimulated AC in both eccrine and apocrine glands. In the secretory cells, enzymatic activity was associated with membranes involved in the secretory mechanism. In both glands, the cells of the excretory duct and myoepithelial cells presented AC activity. These localizations of enzymatic activity suggest a role for PACAP in regulating glandular secretion.