Pituitary ACTH responsiveness in the vasopressin deficient rat.

ACTH concentration and the responsiveness of dispersed anterior pituitary cells to hypothalamic extract and to vasopressin were studied in homozygous (DI), heterozygous (HTZ), DI-pitressin treated (DIP) Brattleboro rats, and in control Long-Evans rats.Absolute, but not relative, anterior pituitary weights of HTZ, DI, and DIP animals were significantly smaller than those of controls. The concentration of immunoreactive (I) and bioreactive (B) ACTH in dispersed anterior pituitary cells was greater in DI and DIP than in HTZ or in control animals, although the total amount of ACTH was greater in control than DI or HTZ animals. Media from incubates of pituitary cells derived from DI and DIP animals contained less I and B ACTH than those from HTZ or control animals. Pituitary cells derived from DI animals secreted markedly less ACTH following incubation with hypothalamic extract (NIH-HE-RP-1) than did cells from HTZ animals. The response in DIP animals was intermediate between that of DI and HTZ animals. In contrast, pituitary cells derived from DI and DIP animals were significantly more responsive to vasopressin than those from control or HTZ animals.     

Pituitary and extrapituitary effects of somatostatin in normal man.

The effects of synthetic linear somatostatin on basal circulating levels on several pituitary and pancreatic hormones, and of glucose and free fatty acids (FFA) were studied in 6 normal men after an overnight fast. A priming intravenous infusion of 250 mug of somatostatin in 18 sec was followed by a constant infusion of 500 mug over a period of 60 min. A decrease in plasma values of GH, prolactin, TSH, insulin and glucagon and in blood glucose was observed during somatostatin infusion, while FFA levels increased progressively. Plasma IRI and blood glucose increased rapidly when the somatostatin infusion was stopped, while FFA decreased progressively; GH, prolactin, TSH and glucagon remained low as compared to basal levels for one hour after the end of the infusion, i.e. until the end of the experiment. A slight but significant increase of LH and ACTH was observed after the end of the infusion.     

Lung vascular permeability changes in lambs with hyaline membrane disease

To investigate the mechanism of pulmonary edema in hyaline membrane disease (HMD), lymph from the efferent duct of the mediastinal lymph node was collected in premature lambs before and after delivery by cesarean section. Mean lymph flow in 7 lambs with histologically verified HMD increased progressively over 4 h after delivery to 3 times the fetal value, while lymph flow in 7 lambs without HMD increased to 3.5 times at 1 h and decreased thereafter. At 4 h after birth, lung lymph flow was significantly higher in lambs with HMD than in lambs without HMD (0.70 +/- 0.15 (SEM) vs 0.43 +/- 0.07 ml.h-1.kg-1). Lymph/plasma concentration ratio for small endogenous protein fractions (effective molecular radius, 3.6 and 3.8 nm) was significantly higher in lambs with HMD than in lambs without HMD at 2-4 h. Postmortem extravascular lung water was significantly higher in lambs with HMD (6.1 +/- 0.5 vs 4.3 +/- 0.3 ml/g dry lung weight). It is concluded that lung water is high in lambs with HMD, which appears to be a result both of delayed absorption of fetal lung liquid and increased permeability of the pulmonary exchange vessels.