A quantitative histological study of adrenal development during the perinatal period in intact and hypophysectomized pigs

Abstract

Summary -Adrenal growth was studied between D70 of gestation (DO : day of mating) and D6 after birth in 33 fetuses and 11 new-born pigs of the Large White breed. Volume, height and mean surface, were estimated by zone, as well as cell number, cell size and nucleocytoplasmic ratio. The volume increased exponentially. In the cortex it was 4.0 mm 3 , 7.2 mm 3 , 10.5 mm 3 , 33.6 mm 3 , 55.3 mm 3 at D70, D94, D106, D113 and D1-D6, respectively, after birth. In the medulla, the volume was 4.0 MM 3, 6.3 mm 3 , 6.9 mm 3 , 9,6 mm 3 and 20.6 mm 3 at the same stages. This evolution was due to predominant longitudinal stretching between D94 and D106, then thickening, as shown by the relative variations of the height and the surface. The growth of the cortex corresponded to hyperplasia associated with hypertrophy after D110. In the medulla, hyperplasia predominated until D110; this was followed by hypertrophic phase. Twelve respectivement égal à 4,0 mm 3 , 7,2 mm 3 , 10,5 mm 3 , 33,6 mm 3 et 55,3 mm3 à G70, G94, G106, G113, et 1 à 6 jours après la naissance. Pour la médulla, le volume est égal à 4,0 mmS, 6,3 mm 3 @ 6,9 mm 3 , 9,6 mm 3 et 20,6 mm 3 aux mêmes âges. Cet accroissement est dû à un allongement prédominant entre G94 et G106, puis un épaississement, comme le montrent les variations relatives de la hauteur et de la surface. La croissance du cortex correspond à une hyperplasie associée à une hypertrophie après G110. Dans la médulla, une hyperplasie prédomine jusqu'à G110, elle est suivie d'une phase d'hypertrophie. 12 foetus, hypophysectomisés à G44 ou à G55 ont été récupérés à G94, G106 et G 112, au moins 50 jours après l'opération. L'hypophysectomie n'a eu aucun effet sur le développement de la médulla (volume, nombre de cellules) mais elle a inhibé de façon très significative la croissance de la zone corticale, essentiellement, celle de la zone fasciculée.porc -foetus -nouveau-né -surrénales -volume -surface -nombre de cellules

Development, Maintenance, and Function of the Adrenal Gland in Early Postnatal Proopiomelanocortin-Null Mutant Mice

“…This is in contrast to conclusions drawn from results in other experimental systems reported in the literature. Experiments with hypophysectomized fetal sheep (35,36) or pigs (37) showed significant perinatal inhibition of growth of the adrenal cortical zone, particularly that of the zona fasciculata, but normal adrenal medullar development, as judged by volume and number of cells. Glucocorticoid treatment of pregnant rats resulting in decreased availability of ACTH in the fetus led to considerable atrophic changes in adrenocortical cells (38) as well as in adrenal medulla (39) in offspring.…”

Pituitary-Interrenal Interaction in Zebrafish Interrenal Organ Development

“…Thus, data on fetal and neonatal Tpit (Ϫ/Ϫ) mice are needed to assess the specific influence of pituitary corticotrophs on prenatal development of the adrenal gland. Results obtained in hypophysectomized fetal sheep and pigs have demonstrated that hypophysectomy inhibits the intrauterine growth of the adrenal cortex, particularly of the zona fasciculata (37)(38)(39). However, in these models, analysis is restricted to later stages of gestation, thereby precluding analysis of early loss of corticotroph function.…”

Distribution between Protein-Bound and Free Forms of Plasma Cortisol in the Gilt and Fetal Pig Near Term

“…Adrenal weight, the ratio of adrenal weight to body weight, and in vitro production of cor ticosteroids increase in the pig fetus in the last days of prenatal life [2,5,27], A recent study demonstrated that pigs with low birth weights had increased relative adrenal weight, plasma total cortisol and CBG binding capacity at 3 and 7 days of age compared with high birth weight pigs [30], In the 114-day-old fetuses of our study, body weight was likewise corre lated with total cortisol (r = -0.29, p < 0.05) and CBG binding capacity (r = -0.37, p<0.05), as well as total protein (r = -0.28. p<0.05), albumin (r = -0.42, p < 0.01), per centage of albumin-bound cortisol (r = -0.40, p < 0.01), and free cortisol levels (r = -0.31, p < 0.01). Conversely, the lighter pigs at this age had a lower percentage of CBG-bound cortisol (r = 0.31, p < 0.01).…”

“…The physiological significance of increas ing adrenal corticosteroid levels of fetal origin on the initiation of parturition is well docu the increase in fetal corticosteroids results from rapid maturation of the fetal adrenal cortex [2,5] and a greater adrenocortical re sponse to a given level of ACTH nearer term [4].…”