Metallothionein induction by cadmium and zinc in rat secretory organs

Summary Metallothionein (MT) levels were determined in four secretory organs of the rat following administration of zinc (Zn) and cadmium (Cd). The concentrations of MT in the lacrimal, parotid and adrenal glands of untreated rats were in the range of 2.2–4.9 g/g wet weight tissue while in the pancreas it was shown to be 15.2 g/g. Injection of zinc at total doses of 16, 32 and 80 mg/kg resulted in a 1.8-, 3.2- and 5.9-fold increase in lacrimal MT content, respectively, while a 10.2- and 13.1-fold elevation was observed following treatment with 4 and 8 mg/kg of Cd, respectively. Similar findings were found in the adrenal gland. The parotid MT was elevated 5.9 and 17 times following Zn treatment at doses of 16 and 80 mg/kg respectively, whereas 4 mg/kg of Cd increased MT 14.4 times in this gland. Pancreatic MT was elevated by 39- and 40-fold after injection of Zn at doses of 16 and 32 mg/kg respectively, whereas 4 and 8 mg/kg of Cd caused a 9.8- and 17.9-fold induction, respectively. These results may indicate that secretory organs participate in metabolism of heavy metals in the mammalian body.     

Metallothionein induction by cadmium and zinc in rat secretory organs

Metallothionein (MT) levels were determined in four secretory organs of the rat following administration of zinc (Zn) and cadmium (Cd). The concentrations of MT in the lacrimal, parotid and adrenal glands of untreated rats were in the range of 2.2-4.9 micrograms/g wet weight tissue while in the pancreas it was shown to be 15.2 micrograms/g. Injection of zinc at total doses of 16, 32 and 80 mg/kg resulted in a 1.8-, 3.2- and 5.9-fold increase in lacrimal MT content, respectively, while a 10.2- and 13.1-fold elevation was observed following treatment with 4 and 8 mg/kg of Cd, respectively. Similar findings were found in the adrenal gland. The parotid MT was elevated 5.9 and 17 times following Zn treatment at doses of 16 and 80 mg/kg respectively, whereas 4 mg/kg of Cd increased MT 14.4 times in this gland. Pancreatic MT was elevated by 39- and 40-fold after injection of Zn at doses of 16 and 32 mg/kg respectively, whereas 4 and 8 mg/kg of Cd caused a 9.8- and 17.9-fold induction, respectively. These results may indicate that secretory organs participate in metabolism of heavy metals in the mammalian body.     

Ursachen der geschlechtsunterschiedlichen MilchdrÜsengewebsentwickiung bei Ratten

Summary Under the same hormonal conditions, mammary gland growth in adult female rats is more pronounced than in males. Since there are no differences in the glandular development of both sexes, either at birth or at 30 days of life, it is assumed that male rats react less sensitively than female rats in response to a hormonal stimulus with regard to mammary gland growth. It is presumed that androgen influence during the differentiation stage is responsible for the fixation of a decreased sensitivity of the positive feedback-mechanism between estrogens and prolactin secretion in males. Thus changes in sensitivity would be the reason for mammary gland growth in males being smaller than in females under the same hormonal conditions.

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Dieser Arbeit liegen zum Teil die Untersuchungsergebnisse einer SchÜler-Facharbeit von U.Rieser zugrunde.     

Sexually dimorphic response of the mouse submandibular gland to fasting.

The submandibular gland of male mice contained 18% more DNA, 34% more RNA and 63% more protein than that of female mice. After a 48-h fasting, the percent loss of gland weight, protein, RNA and DNA was greater in the female than in the male.     

Immunohistochemical detection of a substance resembling growth hormone-releasing factor in the brain of the rainbow trout (Salmo gairdneri)

We studied the distribution of an immunoreactive substance resembling growth hormone-releasing factor (GRF) in the hypothalamus and pituitary gland of the rainbow trout by immunofluorescence methods. The GRF-like immunoreactive perikaryon was observed in colchicine-treated fish. The majority of GRF-containing neurons were located in the nucleus lateral tuberis; others were located in the caudal part of the preoptic nucleus of the hypothalamus. The GRF-like immunoreactive neuronal processes projected into the pars distalis via the pars nervosa of the pituitary gland. The distribution of the GRF-like immunoreactive substance in the hypothalamus and pituitary gland suggests that GRF plays a physiological role in the regulation of growth hormone release from the pituitary gland of rainbow trout, as it does in mammals.     

Sex steroids in the rat submaxillary gland during the estrus cycle

Relatively high progestagen levels were found in female rat submaxillary glands, with a maximum in the proestrus stage at 22 h and 2 minima; in proestrus between 10 and 14 h, and in estrus at 14 h. Estrogen and androgen concentrations in the gland were undetectable during most of the cycle except in the proestrus stage, when the highest level was determined at 14 h for estrogens and at 17 h for androgens.     

Solubilization of prolactin receptor by a Zwitterionic detergent

Summary About 60% of the prolactin receptors were solubilized from rabbit mammary gland membranes by Zwittergent 3–12. The use of Zwittergent 3–12 resulted in increased sensitivity of the receptor assay and permitted use of ovine prolactin instead of human growth hormone in the receptor assay.Acknowledgments. This work was supported by grant AM 17476 from the National Institutes of Health.     

The pineal gland is very large and active in newborn antarctic seals

Summary The pineal gland of newborn elephant seals and Weddell seals is larger than in adult females. The gland is considerably larger at birth in Weddell seals than in elephant seals. The former experience greater extremes of temperature. Plasma melatonin concentrations in excess of 2000 pg/ml were recorded in the first days of life, compared with 20–50 pg/ml in adults.Acknowledgment. We thank members of the Australian National Antarctic Research Expedition to Macquarie Island for assistance with collection of elephant seal samples, in particular G. Burns, D. Carroll, G. Copson, R. Ledingham and S. Pye. The support of the National Science Foundation, USA, and personnel at the United States Antarctic Research Program base at McMurdo Sound, Antarctica, are gratefully acknowledged. The Tasmanian National Parks and Wildlife Service kindly issued permits to collect specimens at Macquarie Island.     

Estimation of the methylating capacity of the pineal gland. With special reference to indole metabolism

In order to obtain more information on the methylating capacity of the pineal gland, a method determining the formation of different 5-methoxyindoles in the pineal gland was developed. The method depends on measuring the incorporation of labelled methyl groups into the various hydroxyindoles present in the pineal gland, after incorporation of pineal tissue with labelled S-adenosyl methionine. Hydroxyindoles were not added to the incubation medium. After incubation thin-layer chromatography was performed with pineal tissue together with the incubation medium; the spots were scraped and counted.     

Immunohistochemical detection of a substance resembling growth hormone-releasing factor in the brain of the rainbow trout (Salmo gairdneri)

Summary We studied the distribution of an immunoreactive substance resembling growth hormone-releasing factor (GRF) in the hypothalamus and pituitary gland of the rainbow trout by immunofluorescence methods. The GRF-like immunoreactive perikaryon was observed in colchicine-treated fish. The majority of GRF-containing neurons were located in the nucleus lateral tuberis; others were located in the caudal part of the preoptic nucleus of the hypothalamus. The GRF-like immunoreactive neuronal processes projected into the pars distalis via the pars nervosa of the pituitary gland. The distribution of the GRF-like immunoreactive substance in the hypothalamus and pituitary gland suggests that GRF plays a physiological role in the regulation of growth hormone release from the pituitary gland of rainbow trout, as it does in mammals.     

Effect of hormones and cyclic AMP on γ-glutamyltranspeptidase activity of rat mammary gland explants

Summary -Glutamyl transpeptidase activity was assayed in midpregnant rat mammary gland explants at 14, 22 and 38 h, in the presence and absence of insulin, prolactin and corticosterone. With these 3 hormones the explants attained the characteristics of a secretory gland after 22 h of tissue culture, at which time the enzyme exhibited its maximal activity. The addition of dibutyryl cyclic AMP in the presence of the 3 hormones produced a significant increase in enzyme activity, which was maximal with a 1 mM concentration of the cyclic nucleotide. A similar effect was observed when theophylline or theophylline plus dibutyryl cyclic AMP were added to the culture medium.This work was supported by grant B1138-8333 from the Departamento de Desarrollo de la Investigación, Universidad de Chile.     

Dipeptidyl aminopeptidase in neonatal rat brain regions

Summary Changes in the activity of dipeptidyl aminopeptidase in rat pituitary gland and various brain regions were examined at 3, 5 and 20 weeks of age. The enzyme activity per g tissue wet weight in pituitary gland was the highest of all tissues studied. Subcellular distribution of the activity was also studied. The highest enzyme activity was found in a crude mitochondrial fraction including synaptosomes.     

Development of rhythmic melatonin synthesis in cultured pineal glands and pineal cells isolated from chick embryo

The chick pineal gland exhibits circadian rhythms in melatonin synthesis under in vivo and in vitro conditions. A daily rhythm of melatonin production was first detectable in pineal glands isolated from chick embryos at embryonic day 16 and incubated under a LD cycle. All pineal glands isolated from 17-day-old and older embryos were rhythmic while no gland isolated at embryonic day 14 and 15 exhibited a daily rhythm in melatonin synthesis. Melatonin production in static cultures of embryonic pineal cells was rhythmic over 48 h if the cells were kept under a LD cycle. When embryonic pineal cells were incubated in constant darkness the rhythm in melatonin production was damped within 48 h. These results suggest that chick pineal cells from embryonic day 16 onwards are photosensitive but that the endogenous component of the melatonin rhythm is not completely developed at that age. A soluble analogue of cAMP stimulated and norepinephrine inhibited melatonin synthesis in cultured embryonic pineal cells. These findings indicate that the stimulatory and inhibitory pathways controlling melatonin synthesis in the mature pineal gland are effective in pineal cells isolated from chick embryos at least 2 days before hatching.     

Immunocytochemical reaction of a haemocyanin antibody in the midgut gland ofNautilus (Cephalopoda,Tetrabranchiata)

The branchial gland of the dibranchiate cephalopods is described as the site of haemocyanin synthesis. Because there is no equivalent to this organ in tetrabranchiate cephalopods the localization of haemocyanin synthesis remained unknown for a long time. In this study we could confirm the conclusions from prelimnary investigations concerning the copper content of the midgut gland ofNautilus, which gave the first indications for a possible localization of haemocyanin synthesis in this organ. We developed a polyclonal antibody againstNautilus haemocyanin, tested its specificity, and used it on ultra-thin sections of the tissue of the midgut gland. It could be shown that there is a clear imunogold precipitation only on the triangular basal cells in the terminal alveoli. All the other types of cell in this organ were free of any immunoreactivity. It can be supposed that the triangular basal cells in the terminal alveoli of the midgut gland are the sites of haemocyanin synthesis inNautilus.     

3-Ethyl-2,5-dimethylpyrazine,a component of the trail pheromone of the antMessor bouvieri

Summary 3-Ethyl-2,5-dimethylpyrazine, found in the poison gland of workers, induces trail following in the Mediterranean harvester antMessor bouvieri. The poison gland contains on average 9 ng of this trail pheromone component. The alkaloids anabasine and anabaseine are also present in this gland, but induce no reaction in workers. Trail following is also induced by substances present in the Dufour gland, but the combined effect of both glands shows no synergism.     

Aplysianin-A,an antibacterial and antineoplastic glycoprotein in the albumen gland of a sea hare,Aplysia kurodai

Summary Aplysianin-A, an antibacterial and antineoplastic factor in the albumen gland of the sea hareAplysia kurodai, was isolated. It had a molecular weight of approximately 320 kD and consisted of subunits with a molecular weight of 85 kD. It contained 9.8% neutral sugar. Aplysianin A showed 50% inhibition ofBacillus subtilis growth at a concentration of 4 g protein/ml and 50% lysis of murine MM46 tumor cells at 14 ng protein/ml. A partial identity of antigenic specificity of the purified specimen with an antineoplastic factor fromAplysia eggs was observed in immunodiffusion tests.Acknowledgment. We are indebted to the staff of Fisheries Research Laboratory, Faculty of Agriculture, University of Tokyo, Maisaka, for the collection of sea hares.     

Sexually dimorphic response of the mouse submandibular gland to fasting

Summary The submandibular gland of male mice contained 18% more DNA, 34% more RNA and 63% more protein than that of female mice. After a 48-h fasting, the percent loss of gland weight, protein, RNA and DNA was greater in the female than in the male.This study was supported by the U.S. Public Health Service Research Grant CA 17038. The authors are indebted to Mr I. Borcsanyi for his technical assistance.     

(Z,E)-α-farnesene,main constitutent of the hypertrophied Dufour's gland of the major workers ofPheidole pallidula (Formicidae)

Summary In the European dimorphic ant,Pheidole pallidula, the Dufour's gland of the major workers is hypertrophied and secretes nearly pure (Z, E)--farnesene. This compound is also present in the Dufour's gland of the minor workers but constitutes only around 10% of the volatiles. Chemical polymorphism inP. pallidula is different from that already reported for species ofPheidole from the New World.Aspirante au Fonds National de la Recherche Scientifique.Maître de recherches du Fonds National de la Recherche Scientifique.     

Autoradiographic studies on RNA synthesis and transport in the Salivary gland ofLygaeus sp. (Hemiptera-Lygaeidae)

Summary Autoradiographic studies using³H-uridine in the salivary gland of adultLygaeus sp. were carried out. The gland cell nuclei, particularly the multiple nucleoli, are the sites of incorporation of the label exhibiting RNA synthesis. The labelled molecules (RNA) are transported to the cell cytoplasm and then into the gland lumen in which no turnover of the radioactivity is observed.I am grateful to my teacher, Prof. P. S. Ramamurty, School of Life Sciences, University of Hyderabad, for his constant inspiration. Grateful acknowledgement is made to Prof. J. P. Thapliyal, Dept of Zoology, B. H. U. for encouragement and to Dr Om Prakash, Dept of Biochemistry, B. H. U. for his valuable criticism.