title: Variation in size of the 'readily releasable pool' of luteinizing hormone during the oestrous cycle of the rat.
abstract: The size of the 'readily releasable pool' of luteinizing hormone at various times of the oestrous cycle has been determined by injecting a supramaximal dose of luteinizing hormone releasing factor (LH-RF) i.v. into rats anaesthetized with sodium pentobarbitone. In an attempt to block replenishment of the 'pool' during release, cycloheximide was administered 30 min before LH-RF. A 20-fold increase in pool size occurred between the morning of dioestrus and the evening of pro-oestrus in the absence of any significant change in total pituitary content of LH. This suggests that increased responsiveness may be brought about by a change in the receptor-release apparatus and/or a transfer of LH from a 'storage pool' which leads to an apparent increase in the proportion of LH available for release.
mesh_terms: D000818:Animals; D003513:Cycloheximide / Q000494:pharmacology; D004971:Estrus; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D011247:Pregnancy; D051381:Rats
chemical_list: D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D003513:Cycloheximide