title: Cytological changes of the pituitary basophils in rats slowly infused with LRH and with LRH and THR in combination.
abstract: Young male rats were iv infused with synthetic LRH (L) and with L and TRH (T) in combination for 1, 3, 24, 48 and 72 hrs at each dose of 1 microgram/hr. All the basophils of the controls infused with saline are divided into the continuous cyclic types, i.e., II-, II/III, III-, III/IV- and III/IV/II-types. The II-, III- and III/IV-type cells correspond, in fine structure, with those of the classical thyrotrophs, LH- and FSH-gonadotrophs, respectively. A 1-hr infusion of L does not induce any serious changes in all the basophils. After a 3-hr infusion of L, the II-type cells disperse from the gland, while the III/IV-type cells diminished the number of their small secretory granules, and the lumina of endoplasmic reticulum are closed. After a 24-hr infusion, the irregularly shaped III/IV/II-type cells which may revert from the III/IV- to the II-type cells are accumulated, whose secretory granules are remarkably reduced in diameter (50--100 nm). There is evidence to show the diffusion mechanism of the secretory granules into the ground matrix. After a 48-hr infusion of L, most basophils take an appearance of III/IV/II-type cells; after a 72-hr infusion, all the basophils show the homologous fine structure. Thus, the morphological changes of the basophils following the L infusion resemble intrinsically those following the T infusion (Soji, 1976b). From these results, it is tentatively concluded that L does not act only on the III-type cells analogous to the "LH-cells", but universally upon a series of basophils. The transformations of the III/IV-type cells into the III/IV/II-type ones and those of the II-type ones into the III- or III/IV-type ones due to a slow infusion of L are inhibited to some extent by the infusion of T + L. The granular releases from the III/IV- and II-type cells due to a slow infusion of L are also inhibited to some extent by the infusion of T + L. For this reason, both T and L may act, not synergistically but antogonistically, upon the transformation of a series of basophils and their granular release.
mesh_terms: D000818:Animals; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D006651:Histocytochemistry; D008297:Male; D008854:Microscopy, Electron; D010902:Pituitary Gland / Q000166:cytology* / Q000187:drug effects / Q000648:ultrastructure; D051381:Rats; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*
chemical_list: D007987:Gonadotropin-Releasing Hormone; D013973:Thyrotropin-Releasing Hormone