These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Immunohistochemical detection of progestin receptors in hypothalamic beta-endorphin and substance P neurons of steroid-treated monkeys.
    Author: Bethea CL, Widmann AA.
    Journal: Neuroendocrinology; 1996 Feb; 63(2):132-41. PubMed ID: 9053777.
    Abstract:
    Progesterone (P) acts in the central nervous system to increase prolactin secretion in estrogen (E)-primed female monkeys. beta-Endorphin (BE) and Substance P (SP) are two hypothalamic peptides which increase prolactin secretion when administered to rats and monkeys. Studies were performed to determine if P acts on these two potential prolactin-releasing systems. The presence of a nuclear steroid receptor defines the cell as a target for the cognate hormone. Therefore, the hypothalamic populations of BE and SP neurons were examined for the presence and regulation of nuclear progestin receptors (PR) in spayed, E-treated (28 days) and E + P-treated monkeys (14 days E + 14 days E + P). Hypothalamic blocks were prepared after perfusion fixation with 4% paraformaldehyde. Cryosectioning (10 mu m) was followed by double immunocytochemistry (ICC) for PR (black nuclear stain) and either BE or SP (brown cytoplasmic stain). Sections were processed for ICC at 100- or 200-mu m intervals through the hypothalamic block. Peptidergic neurons with and without PR were counted in each section. The E + P-treated monkeys exhibited a significant increase in serum prolactin. BE neurons were found only in the arcuate nucleus (ARC) and median eminence (ME). The colocalization of BE and PR equaled 2% in spayed controls, 21% in the E-treated group and 25% in the E + P-treated group. SP neurons were located in a dorsomedial hypothalamic (DMH) subpopulation which extended caudally under the mamillary nuclei and in a subpopulation located in the ARC and ME. Neither the DMH or submamillary SP neurons contained PR. The percent colocalization of SP and PR in the ARC/ME equaled 5, 26 and 10% in the spayed, E- and E + P-treated groups, respectively. The decrease in PR + SP colocalization with P treatment is probably due to a decrease in SP and not to a decrease in PR immunoreactivity. In summary, E treatment induced PR in BE and SP neurons. Addition of P to the E treatment did not alter the expression of PR in BE neurons, but PR colocalization decreased in SP neurons. Therefore, it is unlikely that SP neurons could transduce the action of P on prolactin secretion in primates, but BE neurons may play an intermediary role.
    [Abstract] [Full Text] [Related] [New Search]