5 alpha-dihydrotestosterone administration converts indolamine metabolism and porphyrin content of the female Syrian hamster Harderian gland to the male type

The effects of ovariectomy and exogenous androgen administration on the indole and porphyrin metabolism of Syrian hamster Harderian glands were studied. Ovariectomy alone had no effect on any of the parameters analyzed. The administration of either testosterone or 5 alpha-dihydrotestosterone increased the activity of N-acetyltransferase in the Harderian glands. However, androgen treatment failed to change the activity of hydroxyindole-O-methyltransferase. Melatonin content of the glands dropped 20 days after treatment with testosterone and 10 days after the administration of 5 alpha-dihydrotestosterone. The porphyrin content of the Harderian glands was dramatically depressed after the administration of either androgen. It is concluded that the Harderian glands of Syrian hamsters are under an androgenic control involving 5 alpha-dihydrotestosterone.     

The androgenic effect on the fine structure of the harderian gland in the male hamster

Summary A sexual dimorphism of the hamster Harderian gland at the ultrastructural level has been reported. The effect of testosterone on the fine structure of the gland from castrated male golden hamsters is reported here. Harderian glands from the following three groups of animals were examined at regular intervals up to 60 days after castration: (1) castrated; (2) castratedsham-injected, receiving 0.1 ml sesame oil per day; (3) castrated-testosterone injected, receiving 2mg testosterone propionate in 0.1 ml sesame oil per day. In groups 1 and 2, clusters of cylindrical tubules, typical of the male gland, decreased in number and disappeared almost completely 2 weeks after castration. Membranous structures, typical of the female gland, prevailed in these two groups throughout the remaining period of experiment. On the other hand, these changes were prevented in the group of castrated animals maintained on testosterone propionate. It is concluded that castration modified the ultrastructure of the male hamster Harderian gland toward the female type and that daily administration of testosterone propionate prevented this change.     

The effects of gonadectomy and testosterone treatment on the Harderian gland of the green frog,Rana esculenta

The effects of gonadectomy and testosterone treatment on the fine structure of the Harderian gland in male and female green frogs were investigated in different periods of the year. Gonadectomy, carried out when the glands are in the lowest secretory phase (September), causes degenerative changes consisting of a reduction of the rough endoplasmic reticulum, the appearance of autolysosomes, and an increase of nuclear heterochromatin. These effects can be prevented by testosterone treatment. No castration effects are found during the recovery (November) and enhancement (April-May) phases of secretory activity. The results suggest that the frog Harderian gland's sensitivity to testosterone changes during the annual cycle. The androgen dependence of the Harderian gland is correlated with the presence of androgen receptors in both male and female forgs.     

Sex difference in L-glutamine D-fructose-6-phosphate aminotransferase activity of mouse submandibular gland

L-Glutamine D-fructose-6-phosphate aminotransferase (2-amino-2-deoxy-D-glucose-6-phosphate ketol-isomerase (amino transferring), EC 5.3.1.19) activities in the three main salivary glands of male and female mice were measured. It was found that the activity in the submandibular gland was about 10 times more in females than in males, whereas the activities in the sublingual and parotid glands of males and females were similar. The activity in the submandibular gland of female mice was not affected appreciably by ovariectomy but it decreased to the level in males on injection of testosterone. The activity in males was not affected appreciably by injection of progesterone or 17β-estradiol, but it increased to the level in females after castration. The increased acitivity in castrated male mice was decreased again to the normal level by testosterone injection. Thus, this sex difference is caused by androgen, not by female hormones. On the basis of in vivo experiments using actinomycin D, it was suggested that testosterone produced an “enzyme inhibitor”, which suppressed the enzyme activity in the submandibular glands of androgen-rich animals.     

Sexual dimorphism in N-acetyltransferase activity, hydroxyindole-O-methyltransferase activity, and melatonin content in the Harderian gland of Syrian hamsters: changes following gonadectomy

The activities of N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT) and the melatonin content of the Harderian glands of intact and gonadectomized male and female Syrian hamsters were studied. NAT activity in intact male Harderian glands was twice that of the female. Prepubertal or adult castrated males exhibited a decrease in NAT activity to a level comparable to that seen in the female. Testosterone implants in the castrated males led to a recovery of the original male NAT levels. Intact male hamsters had very low levels of Harderian HIOMT activity and melatonin content in comparison with the glands of the females. Prepubertal gonadectomy but not castration of adult males raised the levels of HIOMT activity and the melatonin content to those of the females. Bilateral ovariectomy had no effect on melatonin content, NAT activity, or HIOMT activity in the female hamster Harderian gland.     

Effect of testosterone on the female hamster harderian gland pigmentation and ultrastructure

Summary Distinct differences occur in the pigmentation and ultrastructural features of the Harderian glands in male and female hamsters. The results of a study on the effect of testosterone on the fine structure of the female Harderian glands are presented here. Glands from three groups of hamsters were examined at intervals up to 49 days: (1) testosterone injected, receiving 2mg testosterone propionate in 0.1 ml sesame oil per day; (2) sham-injected, receiving 0.1 ml sesame oil per day; (3) untreated controls. Testosterone injections caused a reduction in the number of dark-brown pigment granules in the acinar cells starting on the 6th day, whereas clusters of tubules, typical of adult male glands, appeared on the 4th day and increased in number thereafter. Lamellar structures, normally present in the female gland, decreased in testosterone treated specimens. These changes reversed after cessation of testosterone treatment. It is concluded that exogenous testosterone administered to female hamsters modifies the pigmentation and ultrastructure of their Harderian glands towards the male type and that this is a reversable phenomenon. There also appears to be an inverse relationship between the presence of tubular clusters in the acinar cells, and the degree of pigmentation.     

Effect of castration and administration of testosterone on cytosol and nuclear androgen receptor in mouse submandibular gland

The effect of castration or administration of testosterone propionate on the subcellular distribution of androgen receptor in mouse submandibular gland was investigated. Within 10 h after castration of male mice, most of the androgen receptor in nuclei was significantly reduced, the androgen receptor in cytosol increased and the increased cytosol receptor retained for at least 40 h. A single injection of testosterone propionate to female mice resulted in the translocation of cytosol androgen receptor to the nuclei by 30 min. The nuclear receptor level remained for at least 24 h and the cytosol receptor was replenished by 24-72 h. These results reveal that the endocrine manipulations such as castration and testosterone injection cause the change in the subcellular distribution of androgen receptor from mouse submandibular gland in both sexes.     

Ultrastructural changes in the uropygial gland of the male Japanese quail,Coturnix coturnix,after testosterone treatment

Summary The ultrastructure of the uropygial gland of the male quail was compared to that of the sebaceous gland of the male rat after castration and testosterone treatment of both species. In intact animals, the differentiating cells of these glands displayed almost the same pattern as regards their smooth endoplasmic reticulum, an organelle involved in lipogenesis in both cases. Castration reduced the volume of this organelle, while testosterone administration restored cell morphology to a normal or supranormal level. Finally, this study showed that at ultrastructural level, there is a close functional analogy between the uropygial gland of quail and the sebaceous glands of rats as regards their androgen dependency. Consequently, the uropygial gland might be an attractive model for study of action of androgens on sebaceous-like glands.     

Development and androgen regulation of the secretory cell types of the Syrian hamster (Mesocricetus auratus) Harderian gland

The secretory cell types of the hamster Harderian glands were studied in both male and female Syrian hamsters. As previously demonstrated, female hamsters showed a single secretory cell type (type I), while male hamsters displayed two secretory cell types (type I and type II). Type-II cells were observed after the first month of age correlating with the increase in testosterone levels. The administration of testosterone to adult female hamsters resulted in a marked increase in the percentage of type-II cells without a significant increase in the number of mitotic figures. Very low levels of serum testosterone were able to maintain the percentage of type-II cells. Castration of male hamsters produced a decrease in the percentage of type-II cells. This drop correlated with the reduction in serum testosterone levels. The chronic administration of a luteinizing hormone-releasing hormone agonist to male Syrian hamsters induced a significant reduction in both serum luteinizing hormone and testosterone. However, the percentage of type-II cells was similar to that of control hamsters suggesting that very low levels of circulating testosterone are able to maintain the percentage of type-II cells. In a final experiment male Syrian hamsters were treated with the antiadrogen cyproterone acetate. No changes were observed in the percentage of type-II cells, whereas serum luteinizing hormone and testosterone levels were significantly modified. We concluded that (1) type-II cells differentiate from type-I cells; (2) gonadal androgens are the major factor controlling this differentiation; and (3) the disappearance of type-II cells after androgen deprivation occurs through holocrine and apocrine mechanisms. The possible implication of 5-reductase in the regulation of secretory cell types in the Harderian glands of hamsters is discussed.     

Organizational effects of estrogen on male-type vulnerability to early weaning

We previously reported that early-weaned (postnatal day 14) male ICR mice, compared to normally weaned animals, exhibited a persistent increase in anxiety-related behavior in the elevated plus maze test. In this study, we examined whether steroid hormone manipulations on postnatal day 0 and at the ages of 2 or 3 weeks affected male-type vulnerability to early weaning. Neither castration nor ovariectomy at the age of 3 weeks affected male-type vulnerability. However, in males, castration at the age of 2 weeks attenuated the increased anxiety levels induced by early weaning, and the implantation of testosterone or estradiol, but not of dihydrotestosterone, restored the effects of early weaning. In contrast, in females, neonatal treatment with testosterone propionate together with testosterone at the age of 2 weeks, which reversed sexual behavior to the male type, did not affect anxiety levels in response to early weaning. When pregnant females were repeatedly treated with testosterone propionate on embryonic days 14, 17, and 19, in addition to testosterone treatment at the age of 2 weeks, the anxiety levels in female were increased by early weaning. Furthermore, the prenatal treatment of estradiol benzoate, but not dihydrotestosterone, induced enhanced anxiety levels by early weaning in females. These results suggest that neural systems are masculinized by estrogen from the embryonic phase to the early postnatal period and are responsible for the high levels of anxiety elicited by early weaning.     

The effects of bromocriptine and prolactin on porphyrin biosynthesis in the Harderian gland of the male hamster,Mesocritecus auratus

Porphyrin biosynthesis was examined in the Harderian gland of the male golden hamster by fluorometric assays of gland porphyrin content and by measuring the activity of a rate-limiting enzyme for haem biosynthesis, 5-aminolaevulinic acid synthase. Both porphyrin content and enzyme activity are low in normal male glands but were greatly raised in males castrated for 6 weeks. However, porphyrin synthesis remained at basal levels in castrates given the dopamine agonist bromocriptine; this suppression could be reversed by simultaneous prolactin administration, and castrated males receiving prolactin alone exhibited very high enzyme activity and porphyrin content. Bromocriptine also prevents the morphological feminisation of the Harderian gland which would normally occur after castration; again, the simultaneous administration of prolactin permits feminisation to occur. The results support the hypothesis that, while androgens have an inhibitory effect on porphyrin synthesis within this model, other factors, including prolactin, are permissive.Abbreviations ALA 5-aminolaevulinic acid - ALA-s 5-aminolaevulinate synthase - GH growth hormone     

Testosterone increases N-acetyltransferase activity in both male and female Syrian hamster harderian glands

N-acetyltransferase (NAT) activity was studied in the Harderian glands of intact and castrated (with or without subcutaneous testosterone implants) male and female Syrian hamsters. Castration in male hamsters produced a significant drop in the NAT activity. Castrated males with testosterone implants had NAT activity levels comparable to those in intact males. Ovariectomy did not modify NAT activity. Ovariectomized hamsters with testosterone implants exhibited a significant increase in the Harderian NAT activity reaching the same values as those in the glands of the male hamsters.     

Sexual differences and effects of castration on secretory mode and intracellular calcium ion dynamics of golden hamster Harderian gland

The aim of the present work was to study the sexual differences in secretory mechanisms and intracellular calcium ion dynamics in the Harderian gland of the golden hamster. In both sexes the Harderian gland consisted of small and large lobes. In the intact control male glands the secretory portions of both lobes showed wide lumina that contained secretory material and cytoplasmic fragments, suggestive of the occurrence of exocytosis and apocrine secretion. After perfusion with HEPES-buffered Ringer's solution containing 10 microM carbamylcholine (CCh), the glandular cells showed features of enhanced secretion and a rise in intracellular calcium concentration ([Ca2+]i). In the intact control female gland the lumina of most secretory portions in the large lobe contained porphyrin accretions, and exocytosis was the sole secretory mechanism. Stimulation of the large lobe with 10 microM CCh did not raise [Ca2+]i or cause enhanced secretion. The small lobe in females resembled the male gland in secretory functions, and CCh administration caused enhanced secretion and a rise in [Ca2+]i. Castration in males abolished apocrine secretion; exocytosis became the sole secretory mechanism, and stimulation of the glandular cells with CCh did not cause enhanced secretion or induce a rise in [Ca2+]i. To the contrary, in females, castration restored apocrine secretion and CCh administration caused enhanced secretion and a rise in [Ca2+]i. Castration did not affect the secretory mechanisms and the effect of CCh on the glandular cells in the small lobes of both male and female glands. The present study points to the possibility that sex hormones may control the functioning or expression of muscarinic receptors in the Harderian gland of the golden hamster.     

The Harderian gland of the Mexican volcano mouse Neotomodon alstoni alstoni (Merriam 1898): a morphological and biochemical approach

The Harderian glands of rodents are large intraorbital exocrine glands with histologic organization that varies among mammalian species. Here we describe some ultrastructural and biochemical features of the Harderian gland in the Mexican volcano mouse Neotomodon alstoni alstoni, a species of restricted habitat. The Harderian glands from male and female adult mice were dissected, processed and embedded in Epon 812 for light and electron microscopy studies. Porphyrin and total lipids were biochemically determined. The macroscopic appearance of the Harderian gland is similar in the male and female. The gland is a bilobulate structure, situated in the orbit towards the posterior side of the eyeball, of whitish color and is surrounded by a connective tissue capsule. The male gland is slightly heavier (127 mg) than that of the female (113 mg). The Harderian gland shows a tubulo-alveolar organization and is composed exclusively of one type of secretory cells. No branched duct system within the gland was found. Adrenergic nerves endings and mast cell were observed in the interstices of the alveoli. Male and female glands produce similar levels of porphyrins. Triglyceride levels were significantly higher (P < 0.05) in the female compared to the male. Abundance of lipids could induce corneal lubrication of the Harderian gland which may confer a protective and adaptative function to the volcano mouse in its natural habitat during the dry and cold seasons.     

Sex differences in secretion pattern of neonatal rat Harderian gland under various environmental lighting conditions

1. Secretion pattern of Harderian gland of neonatal rats maintained under (a) diurnal lighting conditions; (b) continuous light or (c) continuous darkness was studied at light microscopy level. 2. All animals were placed in especially designed cages at 13:00 hr on day 1 and studied on day 7 at 13:00 and 23:00 hr, respectively. 3. Acini with intraluminal secretion were counted in glands from each animal and the results were separately grouped for male and female animals. 4. A diurnal rhythm in secretion pattern of rat Harderian gland in neonatal period was demonstrated. 5. A statistically significant difference was observed in the gland secretion pattern between males and females at both, 13:00 and 23:00 hr when the animals were kept under diurnal lighting conditions. 6. Under continuous light or continuous darkness, the diurnal rhythm in secretion pattern was lost and no significant differences were seen when data from males were compared to those from female neonates. 7. Results are discussed in terms of the possible function of Harderian gland as element of an extraretinal photoreceptor system involved in the regulation of pineal function in neonatal rats.     

Androgen receptor in rat Harderian and submandibular glands

Summary Androgens regulate the development and sexual dimorphism of rodent Harderian and submandibular glands. This effect is believed to be mediated by the androgen receptor. Immunohistochemistry and immunoblotting were carried out to study the receptor in normal, castrated and dihydrotestosterone-supplemented rat Harderian and submandibular glands. Immunohistochemically, the most intense nuclear staining was observed in the acinar cells of the submandibular glands, followed by intercalated duct cells. The granular convoluted tubules showed weak immunostaining and the striated ducts were negative. In the Harderian gland, nuclear staining was seen in both type I and II secretory cells. Castration and treatment had no effect on the expression of the androgen receptor protein in either gland. A 110 K androgen receptor signal was detected by immunoblotting in the Harderian gland but not in the submandibular gland. An experiment was designed to explore the possible effect of proteinases on the receptor protein in the homogenate of submandibular gland. Our results demonstrate the cell-specific location of the receptor in Harderian and submandibular glands, and show that the expression of the receptor protein is androgen-independent.     

Effects of diazepam and its metabolites on nocturnal melatonin secretion in the rat pineal and Harderian glands. A comparative in vivo and in vitro study

We investigated the effects of diazepam (DZP) and its three metabolites: nordiazepam (NZP), oxazepam (OZP), and temazepam (TZP) on pineal gland nocturnal melatonin secretion. We looked at the effects of benzodiazepines on pineal gland melatonin secretion both in vitro (using organ perifusion) and in vivo in male Wistar rats sacrificed in the middle of the dark phase. We also examined the effects of these benzodiazepines on in vivo melatonin secretion in the Harderian glands. Neither DZP (10^-5-10^-6 M) nor its metabolites (10^-4-10^-5 M) affected melatonin secretion by perifused rat pineal glands in vitro. In contrast, a 10^-4 M suprapharmacological concentration of DZP increased melatonin secretion of perifused pineal glands by 70%. In vivo, a single acute subcutaneous administration of DZP (3 mg/kg body weight) significantly affected pineal melatonin synthesis and plasma melatonin levels, while administration of the metabolites under the same conditions did not. DZP reduced pineal melatonin content (-40%), N-acetyltransferase activity (-70%), and plasma melatonin levels (-40%), but had no affects on pineal hydroxyindole-O-methyltransferase activity. Neither DZP nor its metabolites affected Harderian gland melatonin content. Our results indicate that the in vivo inhibitory effect of DZP on melatonin synthesis is not due to the metabolism of DZP. The results also show that the control of melatonin production in the Harderian glands differs from that observed in the pineal gland.     

Influences of gonadal and adrenal androgens on the side glands of Suncus murinus.

In order to know the contribution of adrenal and gonadal androgens to the development of the side gland of Suncus murinus, we studied the effects of gonadectomy and adrenalectomy on gland thickness and the plasma levels of testosterone, androstenedione (delta 4-dione) and dehydroepiandrosterone (DHA). In males, castration decreased gland thickness to 71% of the control. The plasma levels of delta 4-dione and testosterone were also decreased from 4.16 +/- 0.50 and 0.65 +/- 0.10 ng/ml to 1.44 +/- 0.17 and 0.12 +/- 0.02 ng/ml, respectively. Adrenalectomy following castration caused no notable additional decrease in gland thickness, although the plasma levels of delta 4-dione and DHA were further decreased by this treatment. In females, ovariectomy affected neither gland thickness nor plasma androgen levels, except for a peculiar rise in the plasma concentration of delta 4-dione. In contrast, adrenalectomy in addition to ovariectomy decreased gland thickness to 63% of the control and the plasma concentrations of delta 4-dione and DHA from 1.43 +/- 0.26 and 0.43 +/- 0.05 ng/ml to 0.37 +/- 0.11 and 0.10 +/- 0.04 ng/ml, respectively. Therefore, testicular androgens are required for the male side gland to fully develop, whereas in the female adrenal androgens are important for the maintenance of sebaceous gland activity and delta 4-dione is quantitatively more important than DHA. One hour after the intraperitoneal administration of [3H]delta 4-dione, dihydrotestosterone was found to be the major androgen bound to nuclei of the side gland. Thus, the side gland can utilize delta 4-dione as a precursor of a more active androgen.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of sex hormones on lipid content and mast cell number in the harderian gland of the female toad, Bufo viridis

The Harderian gland of the toad Bufo viridis is a dimorphic gland owing to the presence of lipid droplets in the female glandular cells present only during summer months. Ovariectomy causes the disappearence of sudanophilia and estrogen-treatment completely prevents this change, while testosterone-injection has little effect. Estradiol-treatment also provokes a proliferation of the interstitial connective tissue concomitantly with the mast cell number increase. Our results suggest that estradiol acts, stimulating both mast cell and connective tissue proliferation, and plays a role in determining the expression of the female type of the toad Harderian gland.