The effect of hypophysectomy on the gastrointestinal tract

Variations of the intestinal mucosa were studied in male adult Wistar rats on day 8 and day 15 after hypophysectomy. All results were compared with those obtained in pair-fed control rats. Morphological variations were observed at two intestinal levels (high part [hp] and low part [lp] of the jejunoileum) both with morphometrical analysis (villous area, microvillous area, enterocytes, goblet and Paneth cell number, mitotic index...), in light or electron microscopy and with histochemical techniques (proteins, polysaccharides, nucleic acids). Levels of the main intestinal hydrolysis were also measured by means of biochemical assays. Atrophy of the intestinal mucosa was confirmed, but atrophy produced not only a reduction of the villous area (hp = –30%p < 0.01, lp = –22%p < 0.05 on day 8, hp = –25 %p < 0.05 lp = –36% p < 0.01 on day 15) but also a significant decrease of the microvillous area (hp ≈ –39% p < 0.001, lp = –14% p < 0.05 on day 8, hp = –24% p < 0.02, lp = –30% p < 0.05 on day 15) in accordance with a significant decrease of brush border enzyme levels. The atrophy was generalized but concerned mainly the high part of the small intestine and could be attributed mostly to a significant decrease of glandular mitosis (hp = –57% p < 0.01, lp = –77% p < 0.001 on day 8, hp = –74% p < 0.01, lp = -75% p < 0.001 on day 15) without apparent modification of cell extrusion at the top of intestinal villi. Hypophysectomy affected the different cell types of the villous intestinal epithelium in different ways. Absorbing cells were the more reduced in number. Defects of maturation of goblet cells were noted. On the other hand, hypertrophy (p < 0.001) and hyperplasia (p < 0.001) of Paneth cells were observed with a significant decrease of the lytic activity. These apparent discrepancies can be attributed to important cytological variations and partial mucoid transformation of the secretory component of Paneth cells (observed both by histochemical and electron microscopic observation). Cytological variations after hypophysectomy seem to be induced early, since no significant differences could be observed between days 8 and 15 for most of the parameters tested. Direct or indirect (local relay) effect of pituitary function is discussed.

Section: Discussionsupporting

confidence: 79%

Section: Introductionmentioning

confidence: 92%

Histological Variations of Jejunal and Ileal Mucosa on Days 8 and 15 after Hypophysectomy in Rat: Morphometrical Analysis in Light and Electron Microscopy

Bastie¹,

Balas²,

Laval³

et al. 1982

“…It has long been believed that the endocrine system may influence the growth of the human gastrointestinal tract [Jacobson and Magnani, 1964;Schapiro et al, 1970]: severe gastric atrophy [Smith et al, 1961] and pancreas atrophy [Beare, 1947] are known to occur in patients with pituitary insufficiency. The hypophysis is in some ways responsible for maintaning the growth of the gastric mucosa [Crean.…”

Section: Introductionmentioning

confidence: 99%

“…1979] and in patients with ac romegaly [Creutzfeldt et al, 1971]; the latter report has since been retracted, though [Creutzfeld ct al., 1974], Morphological alterations are associated with defects in secretory capacities: reduction in gastric secretory volume, in acidity, in pepsin concentration and mucus content [Schapiro et al, 1970]. The proteolytic [Baker et al, 1956, amylolytic [Barrett et al, 1955;Sesso and Valeri, 1962] and lipolytic [Bicknel!…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of Histological and Kinetic Variations of the Digestive Mucosa and Pancreatic Parenchyma after Hypophysectomy in the Rat

Bastie¹,

Balas²,

Laval³

et al. 1985

Variations of the pancreatic parenchyma, the gastric mucosa and the intestinal mucosa were studied in adult male Wistar rats on day 8 and 15 after hypophysectomy. All results were compared with those obtained in pair-fed control rats. Hypophysectomy affected small intestine as well as gastric mucosa. Hypotrophy was observed on day 8 as most of the morphological parameters reached the maximal decrease. By contrast, hypoplasy occurred on day 15, when the labeling index (LI) decreased significantly. In the intestine, however, a decrease of the LI was observed only for the upper proliferative cells of the crypts. In the gastric mucosa, the LI was reduced only in the proliferative zone containing progenitor cells (isthmic region). Consequently, the cell differenciation is not similarly affected on all levels of the digestive tract.

“…On the other hand hypophyscctomy, involving defi ciency of the growth hormone, caused atrophy of the gastric mucosa [9], of the exocrine pancreatic parenchy ma [33] and of the intestinal mucosa [2, 20. 33].…”

mentioning

confidence: 99%

Long-Term Effect of Somatostatin 14 on Mouse Stomach, Antrum, Intestine and Exocrine Pancreas

Senegas-Balas¹,

Balas²,

Pradayrol³

et al. 1985

Mice were injected 3 times a day for 12 days with 8 µg/kg of somatostatin 14 which caused ahypoplasia of parietal and goblet cells, a hypotrophy and hypofunctionality of pancreatic acinar cells with a decrease in lipase and chymotrypsin activities, a decrease in the secretory function of the Brunner gland and in the number of dark granules of G cells. Neither villous and microvillous areas nor brush border hydrolase activities were affected. The number of peptic cells and Paneth cells increase as the level of pepsin and lysozyme. Mice were injected 4 times per hour with 2 µg/kg of somatostatin. 2 h after the first injection of somatostatin and 90 min after a single injection of tritiated thymidine, fundic, antral, jejunal and ileal labelling indexes strongly decrease (maximal effect in ileum). The inhibitory effect of somatostatin on the digestive epithelial cell proliferation compared to its long-term action only directed on specific cell types evokes probable compensatory mechanisms induced to maintain the equilibrium of the digestive epithelia.