Some new aspects of a sheep pineal gonadotropic inhibiting activity in in vitro experiments

Fluorescence and electron microscopic study of the tree shrew pineal organ

The fine structure of the pineal gland and the pineal innervation in the tree shrew were studied by electron microscopy and glyoxylic acid-induced fluorescence microscopy respectively. The parenchymal cells consist of pinealocytes, glial cells and pigment-containing cells. The pinealocytes are characterized by the presence of granular vesicles, synaptic ribbons, electron-dense bodies and small profiles of rER with dilated cisternae. Glial cells contain light cytoplasmic bodies, lipofuscin granules, bundles of microfilaments, and elongate profiles of rER with flattened cisternae which are often stacked together with light cytoplasmic bodies; the pigment-containing cells are unique in possessing giant pigment granules in the cytoplasm. The pinealocyte/glial cell/pigment cell in tree shrew pineals may be the same cell line of parenchymal cells at different ontogenetic stages. Pigment-containing cells contain pigment granules as a prominent cytoplasmic inclusion, suggesting they are senscent in secretory function. Both pinealocytes and glial cells contain structures suggesting secretory function such as well-developed Golgi complex and granular vesicles. The antigonadotrophic substances may be stored in granular vesicles. The present ultrastructural study supports the conclusion that tree shrew pineal organ is an endocrine gland which is heavily innervated by adrenergic nerves and possibly by cholinergic nerves.

A survey of the location, isolation and identification of indoles, pteridines and some unknown active substances in sheep pineals. The possible significance of pteridines for the neuroendocrine control of neoplastic growth

Several indoles with mass spectra identical to those of synthetic melatonin, 5-hydroxyindole-3-acetic acid (5-HIAA), 5-methoxyindole-3-acetic acid (5-MIAA), 5-hydroxytryptophol (5-HTL) and 5-methoxytryptophol (5-MTL) could be located, isolated and identified in sheep pineal extracts using rather simple and mild extraction and separation methods. An antigonadotropin, which differs from melatonin, was isolated and partially purified from sheep pineals, using compensatory ovarian hypertrophy after unilateral ovariectomy as a bioassay. Antigonadotropic and gonadotropic compounds which differ from the indoles above mentioned could be located with the same methods. In vitro, these fractions act either on the hypothalamus or on the anterior pituitary. From the paper chromatography fraction, acting on the anterior pituitary in vitro, a compound could be isolated which is most probably identical with biopterin. In our opinion, however, this compound is not responsible for the antigonadotropic activity of the fraction, observed in vitro. Some pineal fractions showing an effect on the activity of the hypothalamus or anterior pituitary of male rats and mice in vitro, may be also active in some experimental tumour models. A possible relationship between disorders in pteridine metabolism and neoplastic growth is discussed.

A survey of some active sheep pineal fractions and a discussion on the possible significance of pteridines in those fractions in in vitro and in vivo assays

Aqueous extracts of sheep pineals are separated on Sephadex G-25 fraction with antigonadotropic activity are ultrafiltered through the membrane UM 2. The UM 2 filtrate is subsequently filtered through the membrane UM 05. The actions of the different fractions on the anterior hypophysis and hypothalamus are discussed. The fractions which show an activity are further separated on Sephadex G-10. The active Sephadex G-10 fractions of the UM 05 filtrate acting on the anterior hypophysis in vitro are purified by electrophoresis and paper chromatography. After elution of different fluorescence bands the main inhibitory activity is found in a region, with the same Rf value as synthetic 6-biopterin. Gas liquid chromatography and mass spectrometry studies of the isolated fractions are carried out. The mass spectrum of an isolated compound from that fraction is identical with that of synthetic 6-biopterin. Thinlayer chromatography and the results of the Crithidia fasciculata test reveal that the isolated compound is probably identical with 6-L-erythrobiopterin. The activity of the active paper chromatography fraction (C4) is compared with the activity of three synthetic biopterin-preparations in vitro and in vivo.

Separation of pineal extracts by gelfiltration. VI. Isolation and identification from sheep pineals of biopterin; comparison of the isolated compound with some synthetic pteridines and the biological activity in in vitro and in vivo bioassays

Aqueous extracts of sheep pineal bodies were separated on Sephadex G-25. Two low molecular weight Sephadex G-25 fractions, F2 and F3, were ultrafiltrated through the Amicon membrane UM-2. The UM-2 filtrate was subsequently filtrated through the ultramembrane UM-05 and the UM-05 filtrate was separated on Sephadex G-10 columns. After paper electrophoresis, preparative paper chromatography was carried out. The fluorescent band showing a Rf value identical with synthetic 6-biopterin was eluted; gas liquid chromatography and mass spectrometry of the isolated compound were carried out. The mass spectra of the isolated compound were shown to be identical with synthetic 6-biopterin. The results of the Crithidia fasciculata test and thinlayer chromatography study revealed that the isolated compound is identical with 6-L-erythro-biopterin. The activities of the isolated compound and of synthetic biopterin in in vitro and in vivo bioassays are demonstrated.

Separation of pineal extracts by gelfiltration. V. Location by paper chromatography of a sheep pineal principle inhibiting hypophyseal gonadotropic activity

Previously we were able to isolate by simple and mild methods from an aqueous sheep pineal extract an inhibiting principle action on the anterior hypophysis of male rats in vitro. This substance could be located by paper electrophoresis. In the present paper we describe the further purification of this active principle by paper chromatography in two different solvents. In two regions possessing a special fluorescence an inhibiting factor of the gonadotropic activity of the anterior pituitary was found in vitro.

Separation of pineal extracts by gelfiltration. III. Sheep pineal factors acting either on the hypothalamus, or on the anterior hypophysis of mice and rats in in vitro experiments

Some compounds, other than melatonin, can be detected in aqueous extracts of sheep pineals, using in vitro bioassays. Mild and simple separation methods are used such as gelfiltration on Sephadex G-25, ultrafiltration through Amicon ultramembranes UM-2and UM-05, followed by gelfiltration on Sephadex G-10 and paper electrophoresis. Some fractions are acting on the hypothalamus, others on the anterior hypophysis of mice and rats. The results are compared with those obtained previously with different extraction and separation methods. Key words: Pineal extract, pineal activities in vitro experiments, hypothalamus, anterior hypophysis, paper electrophoresis.