Antidiuretic hormone in the urine and pituitary of the kangaroo rat

The isolation, identification and properties of the hormonal granules of the neurohypophysis

Methods for the preparation of cell fractions from homogenates of the posterior pituitary glands of rabbits are described. By controlling the speed of centrifugation it was possible to isolate 80% of the oxytocin and vasopressin in a sedimentable form and about half of the total hormones or two-thirds of the sedimentable hormones in a single fraction. Electron microscopy of this fraction showed that it was composed mainly of membrane-bounded granules about 1300 Å in diameter. Similar granules were found in the neural swellings of the rabbit neurohypophysis studied by electron microscopy. The possibility that vasopressin and oxytocin are stored in different granules is discussed.

Supraoptic neurosecretory cells: adrenergic and cholinergic sensitivity

Adrenergic and cholinergic agonists and antagonists were applied microelectrophoretically to over 700 neurons in the cat supraoptic nucleus, 20 percent of which were antidromically identified as neurosecretory cells. Norepinephrine uniformly depressed all sensitive cells. Acetylcholine caused both muscarinic depression and nicotinic excitation which were antagonized by atropine and dihydro-beta-erythroidine, respectively. These results support the hypothesis that norepinephrine and acetylcholine are directly involved in controlling the release of antidiuretic hormone.

Comparison of the effects of water deprivation and sodium chloride imbibition on the hormone content of the neurohypophysis of the rat

1. Vasopressin and oxytocin have been measured in the neurohypophysis of rats which had either been given a 2% (w/v) NaCl solution to drink or been deprived of drinking water for up to 5 days.2. There was a progressive decrease in the vasopressin content of the glands in both groups; the rates of depletion were not significantly different.3. Oxytocin also decreased progressively in both groups but the glands from the ;saline-treated' rats contained less hormone than those from the ;water-deprived' animals.4. The differences in gland content of oxytocin could not be correlated with differences between the plasma osmolalities or sodium concentrations of the two groups.