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H Margolis-Kazan

Publications and source records attributed to H Margolis-Kazan.

15 recordsLinked to original sources
PubMed1985

Immunocytochemical localization of serotonin in the brain and pituitary gland of the platyfish, Xiphophorus maculatus.

Immunoreactive serotonin (ir-5HT) containing cells were localized in the brain and pituitary gland of the platyfish by use of immunoperoxidase procedures. In the brain, ir-neurons were found lining the wall of the third ventricle and in its lateral and posterior recesses. More caudally, ir-perikarya were found in the valvular portion of the cerebellum and in the raphe region. Ir-5HT was also localized within the pineal gland in fish that had been sacrificed before 1:00 p.m. Within the pituitary gland, ir-5HT was localized in periodic acid Schiff-positive cells of the pars intermedia of all fish while, in only a few animals, less intense immunoreactivity was also present in gonadotrophs of the caudal pars distalis.

Animals↗
PubMed1985

Immunoreactive tyrosine hydroxylase in the brain and pituitary gland of the platyfish.

Immunoreactive tyrosine hydroxylase (ir-TH), the rate-limiting enzyme for the synthesis of dopamine and other catecholamines, was localized in the brain and pituitary gland of sexually mature platyfish (Xiphophorus maculatus). This is the first report of ir-TH in the nucleus olfactoretinalis, an LHRH-containing nucleus in the brain which plays an important role in the development and functioning of the reproductive system in platyfish. Ir-TH was also localized in the nucleus preopticus and paraventricular organ. In the pituitary gland ir-TH is found in the prolactin cells and in some fish, in some of the gonadotropin-containing cells of the pars intermedia, but not in the gonadotrops of the pars distalis. The localization of ir-TH in brain centers and pituitary cells associated with reproductive system regulation is discussed in the context of the interaction of monamines, neuropeptides and pituitary hormones during the maturation and operation of the brain-pituitary-gonadal axis.

Animals↗
PubMed1984

Structural and functional links between olfactory and reproductive systems: puberty-related changes in olfactory epithelium.

The structural and functional link between olfactory reproductive systems in male and female platyfish (Xiphophorus maculatus) is demonstrated by the connection of receptors in the nasal epithelium to a center in the brain that has a primary role in the development and functioning of the reproductive system. Profound morphological changes occur in the nasal epithelium, and LH-RH content increases in tracts of the olfactory lobe, at specific stages of sexual maturation and not according to chronological age. Our study provides new insight into the development of the mechanisms by which chemical environmental cues are received.

Aging↗
PubMed1984

Sexually dimorphic, age-related changes in pituitary gonadotrop distribution.

Sexually dimorphic, age-related changes occur in the distribution of pituitary gonadotrops in platyfish. In females, shortly after reaching sexual maturity, cells containing immunoreactive gonadotropin begin to appear among the prolactin cells of the rostral pars distalis and they become more numerous with advancing age. In males, if these cells do appear it is almost a year later and they are much fewer in number than in females. Evidence is presented which suggests that the gonadotropin containing cells in the rostral pars distalis are true gonadotrops rather than gonadotropin-secreting prolactin cells.

Aging↗
PubMed1983

The effect of hypophysectomy and gonadotropin administration on the distribution and quantity of LH-RH in the brains of platyfish: a combined immunocytochemistry and radioimmunoassay study.

Radioimmunoassay (RIA) and immunocytochemistry (ICC) were used to study the effect of hypophysectomy (H) on the distribution and quantity of luteinizing hormone-releasing hormone (LH-RH) in the brains of sham-operated-saline-injected, H-saline-injected and H-gonadotropin (GTH)-injected mature female platyfish (Xiphophorus maculatus). In fish hypophysectomized for 5 weeks, there was a decrease in the LH-RH content of the brain (mean +/- S.E. = 446 +/- 31 pg, H-saline-injected; 649 +/- 28 pg, sham-operated-saline-injected). The administration of five 10-micrograms injections of salmon GTH on alternate days beginning in the fifth week of H resulted in a small but significant (P less than 0.05) decrease in LH-RH beyond H-saline-injected group levels (362 +/- 36 pg). The ICC analysis of H fish indicated a decrease in immunoreactive (ir)-LH-RH in the nucleus preopticus periventricularis (NPP) and nucleus lateralis tuberis pars posterioris (NLT), but a marked increase in the immunoreactivity of the neurons in the nucleus olfactoretinalis (NOR). The H fish which received GTH showed a decrease in ir-LH-RH in the NOR, but a slight increase in the NPP and NLT. The results demonstrate that although there is a general decrease in the LH-RH content of brains in H fish as determined by RIA and ICC, one of 3 ir-LH-RH-containing centers of the brain, the NOR, shows a marked increase in ICC-demonstrable LH-RH, indicating that these 3 regions may differ in their roles in the regulation of the reproductive system. The drop in RIA-measurable LH-RH in the brain, along with the enlarged perikarya observed in all 3 regions, suggests that an increase in the synthesis and release of LH-RH occurs in response to removal of the pituitary. The functional significance of the NOR and the feedback mechanisms between brain, pituitary and gonads are discussed.

Animals↗
PubMed1983

Continued reproductive potential in aging platyfish as demonstrated by the persistence of gonadotropin, luteinizing hormone releasing hormone and spermatogenesis.

Male platyfish, Xiphophorus maculatus, ranging in age from 12 to 54 months (normal life span is 30 months), were examined for age-related changes in the distribution of immunoreactive gonadotropin (ir-GTH) and luteinizing hormone releasing hormone (ir-LHRH) in their pituitary glands, and for changes in the histology of their testes. Males sacrificed at 13 and 16 months of age served as controls. Immunocytochemical methods demonstrate that even in the oldest fish, some almost twice the average platyfish life span, ir-GTH and ir-LHRH are localized in the same pituitary cell types in the caudal pars distalis and pars intermedia as in younger sexually mature fish. The testes of old fish continue to contain all stages of spermatogenesis; however, there are age-related increases in the amount of intertubular connective tissue and the relative number of spermatozeugmata, and distortions in the organization of acini. Our observations indicate that GTH and LHRH production and spermatogenesis continue, and thus a potential for reproductive capability persists, in male platyfish up to the time of their death resulting from old age.

Aging↗
PubMed1982

The histochemical localization of steroid binding sites in the pituitary gland of a teleost (the platyfish).

Specific binding sites for estrogen, testosterone, and progesterone have been demonstrated in the pituitary gland of mature male and female platyfish (Xiphophorus maculatus). With a histochemical procedure, fluorescent-steroid-hormone conjugates were localized in the cytoplasm and nucleus of the gonadotrops of the caudal pars distalis (CPD) and in cells of the pars intermedia (PI) previously demonstrated to contain immunoreactive gonadotropin. The specificity of the response was confirmed by means of competitive binding analyses and by using fluoresceinated BSA not linked to steroids. The physiological significance of steroid binding in the PI, as well as in the CPD, is discussed in the light of other recent studies on the pituitary gland of the platyfish.

Animals↗
PubMed1981

Ultrastructural localization of gonadotropin and luteinizing hormone releasing hormone in the pituitary gland of a teleost fish (the platyfish).

Immunoreactive luteinizing hormone releasing hormone (irLHRH) and immunoreactive gonadotropin (irGtH) are demonstrated in the pituitary gland of a teleost fish (Xiphophorus maculatus, the platyfish) at the ultrastructural level. Using a immunoperoxidase procedure, irGtH and irLHRH are specifically localized over the secretory granules of both gonadotropes and some cells of the pars intermedia (PI). All other pituitary cell types lack immunoreactive material. A concept of LHRH receptors on gonadotrope granules is discussed and a new function for a class of PI cells is suggested.

Animals↗
PubMed1981

Cross-reactivity between human and fish pituitary hormones as demonstrated by immunocytochemistry.

In this communication we describe the immunocytochemical cross-reactivity between antisera to various human pituitary hormones and specific hormone producing cell types in the pituitary gland of sexually mature male platyfish (Xiphophorus maculatus). Antisera to human pituitary hormones cross-reacted either with cells known to produce corresponding hormones (or hormone subunits) in the platyfish (e.g., ACTH, prolactin, TSH beta, LH alpha, FSH alpha, TSH alpha) or with no pituitary cells at all (e.g., HL beta, FSH beta). The one exception was antiserum to human growth hormone which cross-reacted with MSH and ACTH producing cells. The platyfish pituitary is proposed as a test system for immunocytochemically screening antisera for purity and specificity in order to determine their applicability in particular studies.

Animals↗
PubMed1979

Identification of luteinizing hormone-releasing hormone (LH-RH) in the brain and pituitary gland of a fish by immunocytochemistry.

For the first time immunoreactive luteinizing hormone-releasing hormone (LH-RH) is demonstrated in both the brain and pituitary gland of a teleost (Xiphophorus maculatus) using an immunoperoxidase procedure. It is specifically localized in the perikarya and their axons of the ventral telencephalon and nucleus lateralis tuberis and within and between the gonadotrops and within some cells of the pars intermedia. These immunoreactions are extinguished when antiserum to LH-RH is preincubated with LH-RH antigen but not with neurohypophysial hormones.

Animals↗
PubMed1979

Effect of tetrahydrocannabinol and ethidium bromide on DNA metabolism and embryogenesis in Volvox.

The effects of delta 9-tetrahydrocannabinol (THC) and ethidium bromide (EB) on the developmental life cycle and DNA metabolism of Volvox carteri have been investigated. THC, previously shown to interfere specifically with cytoplasmic DNA (cDNA) in this organism, was used at different concentrations and at different times during the life cycle. The morphological consequences observed were found to be dependent on the nature and time of treatment. This study also indicates that ethidium bromide induces degradatin of cDNA similar to that mediated by THC. However, unlike THC, it also causes the cessation of nuclear DNA synthesis. The consequences of EB treatment on morphological development are different from those observed with THC. A correlatin of these observations with the biochemical results presented suggests possible models in which the amounts and proportions of nuclear and cytoplasmic DNA play a role in the regulation of embryogenesis in this organism.

Chlorophyta↗
PubMed1976

The DNA of Volvox carteri: a biophysical and biosynthetic characterization.

Various biophysical and biosynthetic characteristics of deoxyribonucleic acid (DNA) from Volvox carteri are examined. The DNA from three strains (HK-10,NB-7 and KA-1) is compared, and all strains are shown to contain at least two distinct DNA species which band at densities of 1.714-1.715 and 1.704-1.705 g/cm3 in neutral CsCl and correspond to nuclear and "cytoplasmic" DNA, respectively. Base compositions calculated from these densities, 55-56% G+C for nuclear DNA, and 45-46% G+C for cytoplasmic DNA, are in close agreement with % G+C values estimated from thermal denaturation data. DNA from strain KA-1 has a third component with a buoyant density of 1.693 g/cm3. DNA synthesis is analysed using radioactively labelled heterogeneously grown strains of Volvox carteri and profiles obtained following preparative CsCl density gradient centrifugation are presented. In addition, dissimilarities in patterns of DNA synthesis at various periods in the asexual life cycle are reported for synchronous cultures of strain HK-10. These differences in temporal patterns of DNA synthesis clearly indicate that while nuclear DNA is make to some degree throughout the life cycle, cytoplasmic DNA synthesis appears to occur only at discrete intervals.

Animals↗