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L Halpern-Sebold

Publications and source records attributed to L Halpern-Sebold.

6 recordsLinked to original sources
PubMed1987

Sexually dimorphic age-related differences in the immunocytochemical distribution of somatostatin in the platyfish.

Somatostatin (SRIF) was localized by immunocytochemistry in the brains and pituitary glands of male and female platyfish (Xiphophorus maculatus) between the ages of 8 and 30 months (average life span is 30 months). In the brain, immunoreactive (ir-) SRIF is found in the perikarya of the ventrobasal hypothalamus (nucleus lateralis tuberis, nucleus anterior tuberis), dorsomedial hypothalamus, dorsal thalamus, ventral tegmentum and rhombencephalic basal plate; in the pituitary it is localized surrounding the ir-growth hormone containing cells of the caudal pars distalis, and in older fish it is also found within certain cells of the pars intermedia. We have demonstrated that there are consistent, sexually dimorphic, age-related changes in the intensity and/or distribution of ir-SRIF. The sexual dimorphism of the changes in SRIF immunoreactivity during the aging of platyfish may be related to the different patterns of growth observed in males and females.

Aging↗
PubMed1985

Sexually dimorphic age-related changes in the distribution of immunoreactive luteinizing hormone releasing hormone in the platyfish.

In this study on platyfish we demonstrate that the distribution and intensity of immunoreactive luteinizing hormone releasing hormone (ir-LHRH) in the brain and pituitary gland fluctuate at specific ages between 8 and 30 months. These changes are not the same in males and females, and they vary for each LHRH-containing region in the brain. In males, ir-LHRH intensity is greatest in the nucleus olfactoretinalis (NOR), nucleus preopticus periventricularis (NPP) and nucleus lateralis tuberis (NLT) at 18 months of age. In females, by comparison, the NOR displays the same degree of immunoreactivity at all ages examined, as does the NLT, where ir-LHRH perikarya are absent at all ages and immunoreactivity is restricted to a few fibers. In the NPP, females show fluctuations similar to those seen in males, however, the intensity of ir-LHRH is always less, and the number of ir-LHRH perikarya appear to be fewer, than in males. Thus, the age-related changes in LHRH systems in platyfish follow different patterns in males and females. Our study clearly indicates that immunocytochemical data must be evaluated with caution and that only after the age and sex of the animal and the maturational state of the gonads have been carefully scrutinized, can meaningful interpretations be made.

Aging↗
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↗
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↗
PubMedDate not supplied

Immunocytochemical changes in serotonin in the forebrain and pituitary of aging fish.

The immunocytochemical distribution of immunoreactive serotonin (ir-5HT) was studied in the forebrain of male platyfish ranging in age from 5 to 30 months (mean life span, 30 months). In fish at all ages, ir-5HT is found in the forebrain in the wall of the third ventricle and its lateral and posterior recesses and in the pituitary in PAS-positive cells of the pars intermedia (PI). With increasing age, ir-5HT first appears in perikarya of the nucleus preopticus (18 months) and in gonadotropes of the caudal pars distalis. Between 8 and 12 months of age, some fish display pale 5HT immunoreactivity in pituitary gonadotropes while in all fish of 18 months and older, the gonadotropes as well as the PI cells show intense 5HT immunostaining. It is suggested that these modifications in serotonin localization may be related to reproductive senescence in platyfish and that they may be associated with other age-related changes in neurohormone and neurotransmitter immunoreactivity. These results are compared with similar age-related changes in the metabolism of neurotransmitters which have been found in mammals.

Aging↗