Hyposmolar stimulation of in vitro pituitary secretion of luteinizing hormone: a potential clue to the secretory process.
Diluting the perifusion medium with water caused a striking prompt increase in LH secretion from perifused, acutely dispersed adenohypophseal cells. The minimum effective proportion of water was 4%; the quantity of hormone secreted was proportional to the dilution of the medium up to greater than 50% water. Secretion was not induced if the dilution was made with 5% aqueous mannitol to maintain isotonicity. The LH secretory responses to hyposmolarity or to LHRH were qualitatively indistinguishable. We suggest that expansion of the outer cell membrane may be an important initial component of the mechanism of secretion from adenohypophyseal cells.
D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D007038:Hypotonic Solutions / Q000494:pharmacology*; D007552:Isotonic Solutions; D007700:Kinetics; D007986:Luteinizing Hormone / Q000378:metabolism*; D008353:Mannitol / Q000494:pharmacology; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014867:Water / Q000494:pharmacology
D007038:Hypotonic Solutions; D007552:Isotonic Solutions; D014867:Water; D007987:Gonadotropin-Releasing Hormone; D008353:Mannitol; D007986:Luteinizing Hormone