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D Croix

Publications and source records attributed to D Croix.

46 records · Page 3Linked to original sources
PubMed1984

[Immunohistochemical arguments in favor of co-localization of neuropeptides in hypothalamo-infundibular neuron systems].

Light and electron microscope methods which can be used to examine the possibilities of co-occurrence of peptides are reviewed. The results obtained using some of them are exposed and discussed, concerning i/the light microscope demonstration of the CRF/vasopressin coexistence in rat and guinea-pig. ii/the electron microscope demonstration of the granular colocalization of LH-RH/C-terminal ACTH and somatostatin/enkephalin in the guinea-pig median eminence.

Adrenalectomy↗
PubMed1981

Comparative immunocytochemical localization of enkephalin and somatostatin in the median eminence, hypothalamus and adjacent areas of the guinea-pig brain.

Because of the presence of an enkephalin-related substance in the somatostatin terminals of the median eminence, an investigation was carried out on the staining for enkephalin of the somatostatin-containing perikarya localized in the hypothalamic periventricular nucleus. Only an occasional and weak enkephalin immunoreactivity was detected in these perikarya, making the common synthesis of the two peptides unlikely. Moreover, our results demonstrate an enkephalin staining in other fibers of the median eminence clearly distinct from the somatostatin ones. Enkephalin was demonstrated in perikarya distributed in the septum, preoptic area, dorsal and ventromedial hypothalamus, all regions known to possibly project into the median eminence. In none of these sites was enkephalin found in association with somatostatin. The present morphological results support the hypothesis that enkephalins may exert their GH-releasing effect at the hypothalamic level and suggest that enkephalins might directly modulate the somatostatin release into the blood of the portal plexus.

Animals↗
PubMed1980

Changes in the LHRH-immunoreactivity of hypothalamic structures during late pregnancy and after parturition in the guinea pig.

LHRH-immunohistochemistry and radioimmunoassay of the gonadotropins were used to demonstrate changes in the LHRH content of the hypothalamus during late pregnancy and after parturition in the guinea pig. Immediately after parturition a decrease in the amount of LHRH-associated fluorescence was observed in the medial preoptic area. Only 12 h later similar changes were found in the median eminence. In the precommissural region no obvious changes were noted in the quantity of LHRH-immunoreactive "terminals" and "synapses". The radioimmunoassay of the gonadotropins shows an increase of LH shortly after parturition which reaches the level of a preovulatory rise, whereas the amount of FSH does not vary significantly. The role of the medial preoptic area and the OVLT in the regulation of the estrous cycle through LHRH is discussed.

Animals↗
PubMed1978

Immunofluorescence study of the hypothalamo-infundibular LRH tract and serum gonadotropin levels in the female squirrel monkey during the estrous cycle.

The study of LRH reactive neurons of the medial basal hypothalamic group was made with rabbit antisera to unconjugated synthetic LRH, in normally cycling female squirrel monkeys. The specifically immunoreactive material present along the hypothalamo-infundibular LRH tract shows significant modifications that are particularly distinct in the lateral, posterior and anterior labia of median eminence, with a maximum concentration during the early and middle follicular phases, a sudden fall to a minimum concentration during the late follicular and ovulatory phases and with a progressive increase during the luteal and early follicular phases. Serum FSH and LH levels show a progressive decrease from the luteal phase to the late follicular phase, with differential modifications suggesting that a double regulation might take place in cycling squirrel monkeys. A parallel is suggested between the specifically reactive material along the hypothalamo-infundibular tract, serum gonadotropin levels and variations in the medial basal hypothalamic and infundibular LRH concentrations during the estrous cycle in the squirrel monkey.

Animals↗
PubMed1976

[Variations in serum LH and FSH during the post natal period of guinea pigs].

LH and FSH are measured by radio-immunoassays in sera of young male guinea Pigs and of females, whose ages range from some hours to 23 days. The curves for the two gonadotropins are not superimposable and are not the same in the two sexes. High concentrations of LH are observed in 8 to 9 day old males; in females, high concentrations of FSH are observed just after the birth and from the 7th to the 10th as well. These facts suggest a dual control of FSH and LH secretion in the guinea pig.

Age Factors↗