title: Suppression of receptors for prolactin and estrogen in rat liver due to treatment with the growth hormone analogue produced by the tapeworm Spirometra mansonoides.
abstract: Somatogenic hormones play an important role in regulation of receptors for prolactin (PRL) and estrogen. Plerocercoids of the tapeworm, S. mansonoides produce a factor which mimics some, but not all of the actions reported for GH. Intact female rats were subjected to a constant infusion of plerocercoid growth factor (PGF) via a subcutaneous infection for two weeks to determine if PGF influences receptors for PRL, GH or estradiol. The rate of weight gain in the PGF-treated rats was accelerated in spite of a marked reduction in serum GH. Partially-purified PGF specifically displaced [125I]hGH from rat liver receptors but microsomes prepared from rats treated with PGF specifically bound significantly less [125I]hGH than microsomes from control rats. The reduction in [125I]hGH binding was not due to occupancy or to a change in affinity but to a suppression in receptor concentration. Scatchard analysis of [3H]estradiol binding in rat liver cytosols shows a 50% reduction in receptor concentration in the PGF-treated group. Specific binding of [3H]estradiol in anterior pituitary was also suppressed by PGF treatment.
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D005260:Female; D013006:Growth Hormone / Q000097:blood; D006133:Growth Substances / Q000494:pharmacology*; D036341:Intercellular Signaling Peptides and Proteins; D008099:Liver / Q000378:metabolism*; D010903:Pituitary Gland, Anterior / Q000378:metabolism; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D011960:Receptors, Estrogen / Q000187:drug effects*; D011979:Receptors, Pituitary Hormone / Q000187:drug effects*; D011981:Receptors, Prolactin / Q000187:drug effects; D011986:Receptors, Somatotropin / Q000187:drug effects
chemical_list: D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D011960:Receptors, Estrogen; D011979:Receptors, Pituitary Hormone; D011981:Receptors, Prolactin; D011986:Receptors, Somatotropin; C043871:plerocercoid growth factor; D013006:Growth Hormone