Osmotic regulation of plasma vasopressin and oxytocin after sustained hyponatremia.

Endogenous pituitary secretion of vasopressin (AVP) and oxytocin (OT) was studied in rats with induced dilutional hyponatremia that was sustained for 2-5 days. Graded infusions of hypertonic saline produced progressive increases in plasma osmolality, but despite large relative increases in osmolality, AVP and OT secretion was not significantly stimulated until plasma [Na+] reached normal ranges. Regression analysis of plasma AVP and OT levels once secretion was stimulated showed no significant shift of the osmotic threshold for neurohypophyseal secretion of either hormone, as well as equivalent slopes of plasma AVP and OT increases per unit increases in plasma osmolality, in the hyponatremic rats relative to normonatremic controls.

In vitro release of vasopressin and oxytocin from rat median eminence tissue.

Release of vasopressin (AVP) and oxytocin (OT) from rat median eminence and posterior pituitary tissue was studied in vitro by incubation in Krebs-56 mM KCl buffer. Both total tissue content and releasable pool of each hormone was measured in control rats, adrenalectomized rats and dexamethasone-treated rats. Adrenalectomy resulted in significantly increased release of AVP, but not OT, from median eminence tissue, whereas dexamethasone treatment failed to affect release of either hormone.

Aircraft noise annoyance at three joint air carrier and general aviation airports.

The results of social surveys conducted near three airports that support both general aviation and scheduled air carrier operations are presented and discussed. Inferences supported by these data include: The nature of noise exposure and community reaction at smaller airports may differ from that at larger airports; survey techniques are capable of identifying changes in annoyance associated with numerically small changes in noise exposure; changes in the prevalence of annoyance are causally produced by changes in noise exposure; and changes in annoyance associated with changes in exposure vary with time.

Reverse-phase purification and silica gel thin-layer chromatography of porphyrin carboxylic acids.

Thin-layer chromatography on silica gel 60 plates in the solvent N,N-dimethylformamide/methanol/ethylene glycol/glacial acetic acid/1-chlorobutane/chloroform (4/35/6/0.4/18/20 by volume) separates porphyrin carboxylic acids by the number of free carboxyl groups. Coproporphyrins I and III and isocoproporphyrin are separated in 30 min, other porphyrins in 15 min.

ADENOSINE 5'-TRIPHOSPHATE-ARGININE PHOSPHOTRANSFERASE FROM LOBSTER MUSCLE: PURIFICATION AND PROPERTIES.

1. A simple chromatographic method is described for the purification of arginine kinase from lobster (Homarus vulgaris) muscle. 2.