Sebaceous Gland Volume Research Articles

578 Targeting PPARγ pathway and protecting skin microbiota balance for sebum harmonization in all skin types

Sebum is a well-recognised protection of the skin and minor changes on its composition and quantity impact skin homeostasis. Over production induces skin microbiota dysbiosis in favor of C. acnes proliferation leading to skin homeostasis dysbalance. Mangifera indica extract was traditionnaly used in folk medicine for its antibacterial and antioxidant properties. In vitro studies demonstrated that the main phytomarker identified, mangiferin, was a potent inhibitor agent of lipogenesis. Sebum regulation was evaluated on sebocytes derived from iPS of African, Asian and Caucasian donors and then by analyzing volume of sebaceous glands in skin explants.

Targeting inflammation and pro-resolving mediators with Anetholea anisita extract to improve scalp condition.

A critical and often-overlooked factor that may give rise to dandruff and oily hair is the intrinsic quality of the scalp stratum corneum (SC), which is often unbalanced and susceptible to external aggressions. Addressing the inflammation element of unhealthy scalp plays an important role in promoting healthy-looking and feeling hair. Although specialized pro-resolving lipid mediators (SPMs) have been studied in the skin to end the inflammation process and promote tissue regeneration, no studies have been provided in the scalp. This study aims to investigate SPMs expression and its role in improving scalp integrity and consequently improving hair appearance using an Anetholea anisita extract. The effect of Anetholea anisita extract was investigated in vitro on human follicle dermal papilla cells (HFDPC), evaluating its antioxidant and anti-inflammatory properties by fluorescence staining and ELISA, respectively. Ex vivo measurement of the volume of human scalp sebaceous glands was performed using X-ray microtomography (micro-CT). The extract was then clinically tested on a population of dandruff sufferers presenting oily hair. Volunteers' sebum was collected on the scalp and analysed by LC-MS/MS or ELISA to identify SPMs and pro-inflammatory markers. Scalp integrity was assessed by measuring the pH and the TEWL. Sebum production, dandruff and hair gloss were also evaluated. Anetholea anisita extract reduced IL-8 and reactive oxygen species (ROS) generation in HFDPC. Interestingly, this extract also decreased the volume of sebaceous glands as revealed by micro-CT. This result was confirmed in vivo by a decrease in sebum production in volunteers. Moreover, SPMs were analysed and detected in the scalp for the first time. An increase in Lipoxin B4 (LxB4) and Resolvin D1 and D2 (RvD1 and RvD2) was observed after Anetholea anisita treatment as well as decrease in pro-inflammatory sebum mediators expression such as PGE2, LTB4 and IL-8. Consequently, the scalp barrier was reinforced as observed through improved transepidermal water loss (TEWL) and skin surface pH, reducing dandruff and improving hair health. The present results suggest the potential of cosmetic applications of Anetholea anisita extract to improve scalp health by targeting inflammation pathways to decrease dandruff and improve hair condition.

Testosterone-related and seasonal changes in sebaceous glands in the back skin of adult male brown bears (Ursusarctos)

Adult male brown bears (Ursus arctos Linnaeus, 1758) display tree-marking behavior to chemically signal their dominance throughout the nondenning period, and this behavior peaks during the breeding season. Within the scent-marking sequence, back rub is a core marking posture. The present study investigated (i) seasonal changes in sebaceous glands in the back skin of brown bears and (ii) the relationship between those changes and testosterone levels. Back skin tissue samples and blood were collected from captive adult intact and castrated males during prebreeding, transitional, breeding, and postbreeding seasons, which were concurrent with back skin observations. In intact males, during the transitional and breeding seasons, an oily secretion from the back skin was observed along with enlarged sebaceous glands. The plasma testosterone concentrations during the transitional and breeding seasons were increased compared with the pre- and post-breeding seasons. Secretions and enlarged sebaceous glands were not found in castrated males, and the plasma testosterone concentrations remained at baseline levels. Oily secretions of the back skin glands that appear more abundant during the breeding season are rubbed against trees. Changes in size and volume of sebaceous glands, and thus their secreting capacity, are likely testosterone-regulated.

Effects of Extracellular Calcium and 1,25 dihydroxyvitamin D3 on Sebaceous Gland Cells In vitro and In vivo

Calcium and 1,25 dihydroxyvitamin D3 (1,25(OH)2D3) are promoters of epithelial cell functions; however their effects on sebaceous glands are unknown. In this study, morphology, ultrastructure, cell numbers, lipid synthesis and apoptosis of SZ95 sebocytes were assessed in vitro under different concentrations of extracellular calcium with or without 1,25(OH)2D3. Moreover, serum calcium and 1,25(OH)2D3 levels were assessed in acne and non-acne patients (controls). Under conditions of low extracellular calcium, lipogenesis and cell detachment were observed. Increasing extracellular calcium enhanced sebocyte numbers, induced epithelial morphology and reduced lipogenesis. Moreover, a reduction in extracellular calcium reduced E-cadherin and enhanced caspase 3/7 activity (apoptosis), whereas calcium chelation by EGTA (ethylene glycol-bis(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid) resulted in enhanced lipogenesis. 1,25(OH)2D3 decreased sebaceous lipogenesis, but also induced signs of autophagy. In the clinical study, patients and controls exhibited normal serum calcium levels. Younger acne patients presented lower 1,25(OH)2D3 levels than did older ones. In conclusion, extracellular calcium and 1,25(OH)2D3 regulate sebocyte morphology, increase cell numbers, decrease sebaceous lipogenesis and induce cell autophagy in vitro. The increased ionized calcium and the reduced 1,25(OH)2D3 levels detected in the serum of younger patients with acne may contribute respectively to increased sebaceous gland volume and enhanced lipogenesis.

Marked Reduction of the Number and Individual Volume of Sebaceous Glands in Psoriatic Lesions

Background: Psoriasis is a chronic inflammatory skin disease characterized by plaques with inflammation, infiltration, hyper-/parakeratosis and desquamation. Microscopic findings in previous studies have revealed some degree of atrophy of the sebaceous glands in patients with psoriasis vulgaris and psoriatic alopecia. Objective: The aim of this study was to investigate possible changes of the sebaceous glands in patients with psoriatic plaques and especially psoriatic alopecia. Methods: Histological and stereological analyses were performed in skin specimens from involved and healthy-looking skin of 14 patients with psoriasis. Stereology detects and quantifies 3-dimensional structures ex vivo. Furthermore, the differentiation process of sebocytes of another 14 psoriatic patients was examined by immunohistochemistry of involved and uninvolved skin specimens. Results: A significant reduction of the number of sebaceous glands as well as of the volume of individual sebaceous glands was assessed in the lesional compared to the nonlesional psoriatic skin. Moreover, it was likely that sebocytes in psoriatic lesions may not differentiate properly. Conclusion: These findings indicate that the sebaceous gland may be a player and not an innocent bystander in the development of psoriatic lesions and especially of psoriatic alopecia.

Abstract P5-09-21: Selective androgen receptor modulators (SARMs): Enobosarm as targeted therapy for the treatment of androgen receptor-positive breast cancer

Abstract Background: The androgen receptor (AR) is the most highly expressed steroid receptor in breast cancer with 75-95% of estrogen receptor (ER)-positive and 40-70% of ER-negative breast cancers expressing AR. Prior studies have shown that women with metastatic breast cancer who have been previously treated with tamoxifen and progress have responded to non-tissue-selective androgens like fluoxymesterone, medroxyprogesterone and danazol, with overall response rates ranging from 20 to 60%. Although these non-tissue-selective androgens have been used to treat breast cancer, the unwanted virilizing side effects, including facial and body hair, enlargement of voice box, acne, and edema, have limited their widespread clinical use. Nonsteroidal, tissue- selective androgen receptor modulators (SARMs) like enobosarm and GTx-027 may provide a novel targeted approach to exploit the therapeutic benefits of androgen therapy in breast cancer without the unwanted virilizing side effects or concerns related to their conversion by aromatase to estrogens. Methods: MDA-MB-231 triple-negative and MCF-7 triple-positive breast cancer cells stably expressing AR (MDA-MB-231-AR and MCF-7-AR, respectively) were used to evaluate the in vitro and in vivo anti-proliferative and gene expression effects of bicalutamide (an AR antagonist), dihydrotestosterone (DHT), enobosarm, and GTx-027. Phase II clinical studies examined the pharmacologic effects (lean body mass and muscle strength), tissue selectivity (skin, endometrium, and hair growth) and safety of enobosarm, a first-in-class SARM, in postmenopausal women. Results: DHT and SARMs, but not bicalutamide, inhibited the proliferation of MDA-MB-231-AR and MCF-7-AR cells. DHT and the SARMs functioned as AR agonists in transactivation assays in MDA-MB-231 cells, indicating that AR agonists, but not antagonists, elicit anti-proliferative effects in breast cancer. MDA-MB-231-AR and MCF-7-AR cells were implanted subcutaneously in nude mice and were treated orally with vehicle or 30 mg/kg/day GTx-027. GTx-027 reduced the tumor growth significantly with greater than 75% tumor growth inhibition observed in MDA-MB-231-AR tumors and greater than 50% tumor growth inhibition observed in MCF-7-AR tumors, compared to vehicle-treated tumors. GTx-027 also inhibited tumor weights by greater than 50% concurring with the tumor volume observation. GTx-027 inhibited the intratumoral expression of genes and pathways that promote breast cancer development through its actions on the AR. Interestingly, GTx-027 and other AR agonists elicited opposite effects on various AR target genes in ER-positive versus ER-negative breast cancer cells, indicating a potential cross talk between AR and ER signaling pathways on the promoter of these genes. Phase II clinical studies showed that enobosarm was generally well tolerated in postmenopausal women. Statistically significant improvements in lean body mass and physical function were observed after 12 weeks of treatment with 3 mg enobosarm, with no significant changes in sebaceous gland volume (biopsy), hair growth, endometrial stripe thickness (transvaginal ultrasound) or bleeding (medroxyprogesterone challenge). Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-09-21.

Structure of solitary sebaceous glands in the Sea Lion eye lid – a Meibomian gland equivalent ?

AbstractPurpose Pinnipeds stay not only in the sea but also on land and may then require a stable tear film. It was of interest to determine whether sea lions have meibomian glands for a superficial lipid layer that prevents tear evaporation.Methods Eyelids of a normal sea lion were embedded in paraffin and sections of 10‐20 µm thickness stained with H&E.Results A distinct tarsus was not detectable, the lid consisted mainly of muscular tissue with the lid margin forming a tip. Underneath the epidermis was a whitish granular layer that consisted of hair follicles and sebaceous glands. Bundles of holocrine acini were arranged between hair follicles. Towards the lid margin, the number of hair follicles decreased whereas the relative volume of sebaceous glands increased. At the lid margin, the sebaceous glands formed solitary glands without association to hairs or with only rudimentary hair shafts. The acini drained via short ductules into a straight duct with a four‐layered stratified squamous epithelium. The straight ducts opened via a terminal duct onto the outer lid skin.Conclusion The results show that pinnipeds have solitary sebaceous glands at the eyelid margin that resemble human meibomian glands in structure but are different in orientation and size. It remains to be determined whether the sea lion eyelid sebaceous glands represent an equivalent to human meibomian glands.

Hidradenitis suppurativa: a disease of the absent sebaceous gland? Sebaceous gland number and volume are significantly reduced in uninvolved hair follicles from patients with hidradenitis suppurativa

The pathogenesis of hidradenitis suppurativa (HS) is not clearly understood. The nomenclature suggests an important role for the apocrine glands but recent evidence implicates the pilosebaceous unit as a more likely candidate to play a central role in the pathogenesis. Our aim was to estimate the volume of the follicular epithelium, the follicular lumen and the sebaceous glands of patients with HS and healthy controls by means of stereology. Four-millimetre punch biopsies were taken from 21 patients with HS and nine healthy controls, fixed in formalin, embedded in paraffin and stained with haematoxylin and eosin prior to volume estimation using the Cavalieri principle. Sebaceous gland tissue could be visualized in only 10 of 15 suitable hair follicle biopsies from patients with HS but was present in all biopsies from healthy controls (P = 0·05) and the mean sebaceous gland volume per follicle was one-seventh of that of healthy controls (P = 0·03). There was no significant difference between patients with HS and healthy controls with regard to follicular epithelium and follicle lumen volume. Our results suggest that the absence or reduced volume of the sebaceous gland may play a role in the pathogenesis of HS. The presence of fibrosis suggests that sebaceous glands are obliterated early in the pathogenesis of HS.

Acne vulgaris

Peripherally active androgens control cellular functions by binding to androgen receptors. Follicular keratinocytes and sebocytes are target cells for androgens, which, directly or indirectly, stimulate keratinocyte proliferation and the volume of sebaceous glands as well as the sebum secretion rate. Acne often begins with the adrenarche, namely with the up- regulation of adrenal synthesis of dehydroepiandrosterone sulfate, a hormone that is upstream to testosterone. The majority of acne patients exhibit normal levels of circulating androgens, while sebaceous glands from acne regions exhibit a stronger sensitivity to androgens than the sebaceous glands from other parts of the body. Hormone-like active lipids, hormones in diet and neuropeptides may also play a role in the development of acne lesions. The target of antiandrogen treatment of the skin is mainly the sebaceous gland and the primary effect is sebostasis.

LBOVI-A-3Identification of skin biomarkers following testosterone administration in postmenopausal women

BACKGROUND/AIMS To pilot a pharmacodynamic (PD) model of short-term androgen administration that may be used to predict long-term effects of androgen administration in postmenopausal women. The study was specifically designed to identify biomarkers that evaluate early skin response to exogenous androgens. The clinical consequences of androgen administration include hirsutism and acne. Skin biopsies were performed to document morphological changes in the pilosebaceous unit (PSU) and gene expression changes (Taqman and microarray). Functional skin response was gauged by measuring sebum excretion rates (SER). METHODS A double-blind, randomized, placebo-controlled, parallel-group study was conducted in 36 healthy postmenopausal female subjects to identify early biomarkers of androgen administration. Subjects were randomized to receive either 2.5 mg of transdermal testosterone gel (TTG; AndroGel®), 300 μg of TTGtransdermal testosterone gel, or placebo gel, daily for 6 weeks in a 1:1:1 ratio. Skin biopsies were performed to document morphological changes in the pilosebaceous unit (PSU) and gene expression changes (Taqman and microarray). Five-mm skin punch biopsies were obtained from the back of subjects at baseline, after 6 weeks of treatment, and 4 weeks post treatment. Biopsies were analyzed for histological changes characterized by total sebaceous gland volume and sebocyte cell size. Skin biopsies were also analyzed for molecular skin changes using skin Taqman/microarray assays. Measurements of sebum excretion rates (SER) were obtained at baseline and after 6 weeks of treatment. RESULTS Six weeks of treatment with the 2.5-mg TTGdose of AndroGel® increased sebaceous gland volume on average by 42% (p=0.0410) and sebum excretion rateSER by 52% (p=0.0021) relative to placebo. Microarray and Taqman analyses on skin samples also demonstrated changes in the 2.5-mg TTG AndroGel® group. Histological and molecular findings were noted to be reversible 4 weeks after discontinuing therapy. Analysis of Total Sebaceous Gland Volume (106 μm3) at Week 6 (See Tables 1 and 2) Mean (SD) % Change from Baseline Treatment N Baseline Week 6 Mean (SD) LS Mean 95% CI Placebo 13 19.58 (32.51) 24.00 (32.27) 4.42 (33.53) 4.42 (−21.79, 30.63) 300 ug TTG 13 37.20 (39.16) 45.59 (47.20) 8.40 (51.97) 8.40 (−17.81, 34.61) 2.5 mg TTG 10 31.93 (36.34) 77.91 (71.76) 45.98 (53.01) 45.98 (16.10, 75.87) Analysis Results for SER at Week 6 Geometric Mean (CV) % Change from Baseline Treatment N Baseline Week 6 Geometric Mean (CV) Geometric LS Mean† 95% CI‡ Placebo 13 0.67 (0.52) 0.67 (0.51) −0.14 (0.29) −0.14 (18.22, −15.65) 300 ug TTG 12 0.81 (0.55) 0.89 (0.56) 10.80 (0.38) 10.80 (32.08, 7.05) 2.5 mg TTG 10 0.82 (0.43) 1.24 (0.42) 52.09 (0.22) 52.09 (84.37, 25.46) CONCLUSIONS TTG treatment is associated with marked increases in sebaceous gland volume and SER, consistent with side effects including hirsutism and acne. Biomarkers sufficiently robust to support using to test for androgen-mediated skin effects in postmenopausal women were identified. Clinical Pharmacology & Therapeutics (2005) 79, P84–P84; doi: 10.1016/j.clpt.2005.12.299

Effect of nutrition on seasonal patterns of LH, FSH and testosterone concentration, testicular mass, sebaceous gland volume and odour in Australian cashmere goats

The effects of season and diet on LH, FSH and testosterone concentrations, testicular mass, sebaceous gland volume and male odour were examined in mature Australian cashmere goat bucks fed ad libitum with diets of low or high quality for 16 months under natural photoperiod at 29 degrees S, 153 degrees E (n = 6 per treatment). Each week plasma was sampled, the bucks were weighed, scored for male odour and assessed for testicular mass based on scrotal circumference. Each month a skin sample was taken from the occipital region for histological assessment of sebaceous gland volume. For each variable there was a clear circannual cycle that was significantly influenced by dietary treatment. In bucks fed the low-quality diet, the timing of seasonal changes in LH and testosterone concentration, sebaceous gland volume and odour score was similar, with a mid-autumn peak. In each case the high-quality diet advanced, extended the duration and increased the magnitude of the seasonal increase. FSH concentrations peaked in late spring (in bucks on the high-quality diet) or summer (in bucks on the low-quality diet), reaching a nadir in early winter. The high-quality diet significantly increased concentrations only in the last 2 months of the experiment (spring). There was no overall association between these variables and change in testicular mass; instead, it was strongly correlated with voluntary feed intake and change in body mass, themselves subject to seasonal variation with a winter or spring peak. The high-quality diet induced large increases in body mass and testicular mass during the first months of the experiment without influencing the seasonally low concentrations of FSH, LH and testosterone present at the time. These results demonstrate that the male, like the female, Australian cashmere goat, exhibits marked reproductive seasonality, and that nutrition is a powerful modulator of the seasonal cycle. They suggest that testosterone concentration, sebaceous gland volume and odour score are ultimately dependent upon LH secretion, which appears to be under strong seasonal (photoperiodic) control, with the effects of enhanced nutrition limited to periods when photoperiodic inhibition is waning. However, seasonal regulation of testicular mass, and therefore sperm production, appears to be primarily dependent on changes in voluntary feed intake and growth, with the seasonal cycle of testicular mass more a consequence of the seasonal appetite or growth cycle than of changing gonadotrophin concentrations.

Effect of oestradiol-17 beta on perineal and neck skin glands in heifer calves.

Ten 16-week-old Friesian x Hereford heifer calves were split into experimental and control groups. Experimental animals were given an implant of oestradiol-17 beta in the ear whilst controls were given blank implants. They were killed 14 days later. After implantation the experimental group had consistently greater (P less than 0.01) plasma concentrations of oestradiol-17 beta than the control group. After death, sebaceous gland volume in the perineal region was greater (P less than 0.01) in the experimental than in the control group, whereas sebaceous gland volume in the neck was smaller (P less than 0.01). Sweat gland volume in the perineal region was greater (P less than 0.01) in the experimental than in the control group. There was no difference between groups in the volume of sweat glands in the neck.

Glycoconjugates in sweat glands and other structures of skin from normal and cystic fibrosis subjects.

In this study, glycoconjugates of human skin varied in structure between cell types in an individual and often between individuals for a given cell type. Stored secretory material in dark cells of the sweat gland coil contained complex carbohydrate with terminal alpha-galactose, N-acetylgalactosamine, fucose, or sialic acid. The plasmalemma of clear cells in the secretory coil stained conspicuously for terminal alpha-N-acetylgalactosamine, and the cytosol of clear cells contained lectin-reactive glycogen in the majority of specimens. Superficial and deep cells of the sweat duct evidenced plasmalemmal glycoconjugate with terminal N-acetylgalactosamine. However, only the superficial cell plasmalemma in the duct stained for terminal alpha-N-acetylgalactosamine, fucose, and sialic acid. In several specimens, only the deep cells in the sweat duct revealed plasmalemmal glycoconjugate with terminal beta-galactose. Sebaceous glands alone displayed lectin affinity demonstrative of terminal alpha-galactose and like other sites stained for terminal beta-galactose and alpha-N-acetylgalactosamine. The epithelium in epidermis and hair follicles appeared similar, except for epidermis failing to evidence fucose and alpha-N-acetylgalactosamine with certain lectins. Both underwent changes in glycoconjugate composition with cell maturation. Skin from control subjects and patients with cystic fibrosis did not differ in lectin-binding properties. Abnormalities observed in cystic fibrosis specimens included decreased volume of sebaceous glands and, in two cases, increased infiltration of macrophages staining for terminal N-acetylgalactosamine.

Histology of moose (Alces alces andersoni) interdigital glands and associated green hairs

The interdigital glands of the moose (Alces alces andersoni) are distinguished from the neighboring skin by the lighter epidermis, green hairs, and huge sebaceous and sweat glands. In the glandular area is a shallow fore pocket and deep hind pocket in both sexes and all ages. Special 250 μm thick sections helped reveal the pilosebaceous–sweat gland unit in both the gland and general body surface. The secretory cycle of the apocrine cells and the cycle's relationship to the lipofuscin cycle are described. Macrophages ingest lipofuscin from moribund apocrine cells. The site of the dead apocrine cell is replaced by neighboring epithelial cells spreading out to fill the gap. The green hairs have a transmittance peak at 515 nm. The chemical nature of the coloring matter is unknown but is probably an organic compound covalently bonded to keratin. The green secretion of the sweat gland in some way dyes the hair. In both sexes the sebaceous gland volume of the gland increases at the rut.

Development of a nude mouse model to study human sebaceous gland physiology and pathophysiology.

Study of human sebaceous gland physiology and pathophysiology is limited by lack of an adequate animal model. This study was designed to develop an animal model using human face skin grafted onto the nude mouse to study human sebaceous glands. Full-thickness human face skin was grafted onto 60 adult male nude mice. 4 wk after grafting, androgens, which are known to stimulate sebaceous glands, were administered to test the system. Androgens were administered to 21 animals by implanted catheters that were filled with testosterone (T) or dihydrotestosterone (DHT). Empty catheters were implanted in 15 control animals. Graft biopsies and blood for androgen levels were obtained at time 1 (pre-catheter) and time 2 (26 d after catheter implantation). Three assessments were made on each biopsy: sebaceous gland volume, using an image analyzing computer; sebaceous cell size; and sebaceous gland labeling index. 29 mice completed the study through time 2. In the androgen-treated group, T levels (nanogram per milliliter) five times increased to 4.92 +/- 0.35, and DHT levels (nanogram per milliliter) increased 50 times to 16.70. In the androgen-treated group, sebaceous gland volume (micron 3 X 10(-3) increased from 896 +/- 194 to 3,233 +/- 754 (P less than 0.001), sebaceous cell area (micron 2) increased from 167 +/- 12 to 243 +/- 19 (P less than 0.001), and labeling index (percentage) increased from 2.7 +/- 0.7 to 6.4 +/- 0.9 (P less than 0.01). In the control group, sebaceous gland volume fell from 1,070 +/- 393 to 417 +/- 99 (NS), sebaceous cell size remained the same, and the labeling index fell from 5.1 +/- 1.9 to 3.2 +/- 1.1. After androgen administration, Halowax N-34, a known comedogen, or its vehicle, was applied to 15 grafts for 2-6 wk. Twice as many microcomedones were seen in the Halowax-treated grafts, compared with vehicle-treated grafts at the end of this time period. No visible comedones were produced. This study demonstrated that: (a) human sebaceous glands can be successfully transplanted and studied on the nude mouse; (b) after androgen stimulation, sebaceous gland volume, cell size, and labeling index increase; (c) microcomedones can be produced in the human skin grafts by the application of a comedogenic substance. Thus, this model demonstrates significant potential for the future study of human sebaceous gland physiology and pathology.

Morphometric Studies of the Hamster Flank Organ: An Improved Model to Evaluate Pharmacologic Effects on Sebaceous Glands

The Syrian golden hamster flank organ, composed of clusters of large sebaceous glands, has been used to investigate effects of systemically or topically applied hormones, antiandrogens, and retinoids. Accurate assessments of flank organ sebaceous gland volume and its correlation with in vivo measurements of flank organ size have not been reported. Sixty flank organs were examined. In vivo flank organ size was expressed as the product of the greatest longitudinal (DL) and greatest transverse (DT) diameters of the palpable bulk. Sebaceous gland volumes were calculated from planimetric analyses of serially sectioned specimens of flank organs using a computer-assisted planimetry system. In vivo measurements (DL X DT) were found to correlate with planimetrically determined flank organ volume. Planimetric analysis of every 10th section of a serially sectioned flank organ was almost as sensitive as analysis of every section in determining sebaceous gland volume. Computer-assisted planimetry of serially sectioned flank organs was found to be an accurate and reproducible method for assessing gland volume. In vivo measurements of the palpable bulk are a good indicator of sebaceous gland size and correlate well with planimetrically determined sebaceous gland volumes.

The Relationship Between the In Vitro Activity of 3β-Hydroxysteroid Dehydrogenase Δ4–5-Isomerase in Human Sebaceous Glands and Their Secretory Activity In Vivo

3 beta-hydroxysteroid dehydrogenase delta 4-5-isomerase (delta 5-3 beta-HSD) catalyzes an early step in the synthesis of testosterone from dehydroepiandrosterone (DHA). We compared enzyme activity in back skin biopsies with sebum excretion rate (SER) in 14 individuals. The rate of conversion of [7 alpha-3H]DHA into [3H]-4-androstene-3,17-dione was measured in cryostat sections of skin and compared with the sebaceous gland content of the same biopsies. Reaction rate was proportional to the volume of sebaceous gland tissue in the sections. Enzyme activity was absent from sections without histologically identifiable sebaceous gland tissue. This suggests that the delta 5-3 beta-HSD is localized in sebaceous glands. SER, measured by a modified photometric technique at the biopsy site, correlated highly with sebaceous gland volume and with the rate of conversion of DHA into androstenedione in the biopsy. For each biopsy, specific activity of delta 5-3 beta-HSD in sebaceous glands was calculated by dividing the rate of formation of [3H]-4-androstene-3,17-dione by sebaceous gland volume. Specific activity of delta 5-3 beta-HSD did not correlate significantly with SER, suggesting that variations in concentration of delta 5-3 beta-HSD in sebaceous glands probably do not underlie variations in sebaceous gland activity.

Effect of alpha-melanocyte-stimulating hormone and testosterone on cutaneous and modified sebaceous glands in the rat.

The effects of alpha-MSH and testosterone propionate on sebum secretion, sebaceous gland volume, dermal lipogenesis, and preputial gland weight and lipogenesis were examined in hypophysectomized rats. Hypophysectomy reduced sebum secretion, sebaceous and preputial gland size, and dermal and preputial gland lipogenesis. The greatest effects were seen on the biosynthesis of wax esters and squalene. Testosterone propionate (TP) increased sebum secretion, sebaceous gland volume and preputial gland weight and lipogenic activity, but had no significant effect on the pattern of lipid labelling. alpha-MSH had no effect on sebaceous or preputial gland size, but increased sebum secretion and dermal lipogenesis, especially wax ester biosynthesis. When given together TP and alpha-MSH had a synergistic effect on sebum secretion and on dermal and preputial gland lipogenesis, and the pattern of lipid labelling was shifted towards normal. TP and alpha-MSH also showed synergism in increasing preputial gland weight, but together they had no greater effect on sebaceous gland volume than that achieved with TP alone. These results suggest that TP and alpha-MSH have different actions on the sebaceous glands with alpha-MSH acting predominantly on lipogenesis and TP on cellualr proliferation and turnover leading to an increase in gland size. Preputial glands differ from cutaneous sebaceous glands in their response to alpha-MSH and androgen which could be a reflection of their more specilized function.

Practical applications of the Quantimet 720, an image analysing computer, in the field of investigative dermatology.

Image analysing computers can perform quantitative measurements of epidermal thickness, sebaceous gland volume, and labelling indices of epidermis easily, rapidly and automatically. All these parameters are extremely important in investigative dermatology and this paper describes how they are measured using the Quantimet 720.

The Mode of Secretion of the Sebaceous Glands of Cattle

Sebum output and sebaceous gland volume and cell number per square metre of skin were measured after stimulation of the glands by cleaning the skin with methanol, and were compared with estimates of glandular mitotic activity. The latter was not altered by a single or repeated stimulation and the number of cells necessary to produce the sebum by a holocrine mechanism greatly exceeded the estimated level of cell production. Sebum output was not associated with the DNA content of skin washings; the DNA was most probably derived from sweat. It was concluded that the mode of secretion of cattle sebaceous glands is unlikely to be holocrine. On mesura le rendement sébacé et le volume des glandes sébacées et le nombre de cellules par mètre carré de peau après stimulation des glandes par le nettoyage de la peau avec du menthanol, et on les compara avec les estimations de l’activité glandulaire mitotique. Cette dernière n’était pas modifiée par une stimulation simple ou répétée et le nombre de cellules nécessaire pour produire le sébum par un mécanisme holocrine excédait fortement le niveau d’estimation de la production cellulaire. Le rendement sébacé n’était pas associé au contenu en ADN des lavages cutanés; l’ADN ne provenait probablement pas de la sueur. Il fut conclu que le mode de sécrétion des glandes sébacées du bétail ne ressemblait pas au mode de sécretion holocrine. Talgproduktion, Grösse der Talgdrüsen und Zeilenzahl pro qm Haut wurden nach vorheriger Stimulierung der Drüsen durch Hautreinigung mit Methanol gemessen und mit einer Schätzung der mitotischen Aktivität der Drüsen verglichen. Diese war durch eine einzelne oder wiederholte Stimulation nicht beeinflusst worden und die zur Produktion von Talg durch einen holokrinen Mechanismus erforderliche Zahl von Zellen war erheblich grösser als die geschätzte Quantität der produzierten Zellen. Die Talgproduktion hatte keine Beziehung zum DNA-Inhalt der Hautwaschungen; DNA stammte vermutlich von der Schweiss-Sekretion. Hieraus schloss man, dass der Mechanismus der Talgsekretion der Rinder kaum holokrin sein kann. Se midieron la salida de sebo y el volumen de la glándula sebácea y el núnero de células por metro cuadrado de piel, después de la estimulación de las glándulas mediante la limpieza de la piel con metanol, y se compararon con estimados de la actividad mitótica glandular. Esta última no se alteró por una sola o varias estimulaciones y el número de células necesarias para producier el sebo por un mecanismo holocrino execieron grandemente el nivel estimado de producción de células. La salida de sebo no se halló asociada all contenido de ADN en las lavazas de la piel; el ADN se derivó probablemente del sudor. Se concluyó que la forma de secreción de las glándulas sebáceas del ganado no es probablemente holocrina.