title: Changes in responsiveness of dispersed pituitary cells to luteinizing hormone releasing hormone at different times of the oestrous cycle of the rat.
abstract: Dispersed pituitary cells obtained from female rats with regular oestrous cycles were suspended in Bio-Gel columns and perfused with pulses of luteinizing hormone releasing hormone (LH-RH). There was a close relationship between the amount of LH released and the concentration of LH-RH in the perfusate. It was not possible to elicit the priming effect of LH-RH, but the LH-response changed markedly during the oestrous cycle in a manner similar to that seen in vivo; i.e. the responses of cells prepared from rats killed at pro-oestrus were much greater than the responses of cells prepared from rats killed on other days of the cycle. A similar change in responsiveness was obtained when the columns were perfused with 60 mmol K+/1, suggesting that at least part of the increase in pituitary responsiveness that occurs at pro-oestrus is not dependent upon changes in specific receptors for LH-RH.
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D004971:Estrus; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D066298:In Vitro Techniques; D007986:Luteinizing Hormone / Q000378:metabolism; D010477:Perfusion; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011247:Pregnancy; D051381:Rats
chemical_list: D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone