The histological changes in the adrenal of the hypophysectomised rat after treatment with pituitary preparations

Abstract

THE activity of adrenocorticotropic hormone (ACTH) may be estimated by three methods :-(1) Adrenal repair or maintenance in the hypophysectomised rat, based upon adrenal weight (Moon, 1936-37 ; Simpson et al., 1943). (2) Histological appearances-the repair of the sudanophobe zone which appears in the hypophysectomised rat (hiss et al., 1936-37). (3) The depletion of the ascorbic-acid content of the adrenal of the hypophysectomised rat one hour after the injection of ACTH (Sayers et al., 1948).St,ack-Dunne and Young (1951) reported that the assay of various pituitary preparations by the adrenal-weight-repair method gave different values from those obtained by the ascorbic-acid-depletion method. They concluded that pituitary preparations contain more than one factor tropic to the adrenal cortex. The present investigation was undertaken to determine if any histological differences could be observed between the adrenal cortex of a hypophysectomised rat t,reated with a pituitary preparation which showed predominantly an effect on the adrenal weight and that of a litter mate treated with a preparation which showed a marked ascorbic-acid-depleting effect. METHODSTwo pituitary preparations were chosen for comparison, namely (1) an ACTH preparation (Armour, batch 84-85 H) and (2) a purified growthhormone preparation.The results of assay of these preparations by the ascorbic-acid-depletion test and the adrenal-weight-repair test are shown in table I. 84-85 H was chosen because it has a low proportion of adrenal-weight (A.W.) activity to ascorbic-acid-depleting (A.A.) activity. Growth hormone was regarded as the most convenient pituitary preparation with a high ratio of A.W. to A.A. activity. A preliminary experiment was performed to establish whether the adrenal weight increase in the A.W. test was due to an enlargement of the cortex or of the medulla. I n the main experiments described below, male albino rats about 8 weeks old were used. Litter mates were hypophysectomised and after 14 days were treated with the pituitary preparations, which were injected intraperitoneally three times daily for three days. The rats were killed by 119

Effect of ACTH on the proliferative and secretory activities of the adrenal glomerulosa

“…Some authors found little or no effect (Cater & Stack-Dunne 1953Bransome & Reddy 1961), others reported an increase in DNA content (Farese & Reddy 1963;Imrie et al 1965;Masui & Garren 1970). In vitro investigations on cells from both the decapsulated adrenal and the gland capsule showed an inhibition of DNA synthesis by ACTH, that is, an inversed relationship between functional and proliferative activities (Ramachandran & Suyama 1975;Ramachandran et al 1977).…”

Expression of extracellular matrix proteins and integrins in rat adrenal gland: importance for ACTH-associated functions

“…In vivo, ACTH does not exhibit the same steroidogenic potency on zona glomerulosa and zona fasciculata. For instance, it is well established that hypophysectomy decreases the volume of zona fasciculata, without affecting the zona glomerulosa (Cater & Stack-Dunne 1953), while ACTH treatment increases the overall volume of the cortex (Mazzocchi et al 1986) and vascularization (Thomas et al 2003(Thomas et al , 2004. From these observations, we raised the hypothesis that the nature of extracellular matrix (ECM) and integrins could influence cell responses to ACTH, as also observed in the human foetal adrenal gland (Chamoux et al 2002).…”

From integrative signalling to metabolic disorders

“…For instance, in vivo, a sodium-deficient diet increases cell proliferation and width of the zona glomerulosa. On the other hand, hypophysectomy decreases [3], while ACTH treatment increases, adrenal gland volume [4] and vascularization.…”