摘要:

The influence of electrical stimulation of various hypothalamic areas on the urinary excretion of testosterone glycuronide (TG) was investigated in the awake, unrestrained, unanesthetized male rat. The urinary TG was determined by means of a gas chromatographic method. Either low-rate or high-rate electrical stimulation of paraventricular, suprachiasmatic and medial tuberal regions elicited a highly significant, short-lasting increase in the urinary TG excretion. No modification in the urinary TG excretion occurred after electrical stimulation of other brain formations as the cerebral cortex or the cerebellum.

ISSN:1663-2818    

DOI:10.1159/000178308

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

The effects of growth hormone administration on in vitro adipose tissue metabolism have been investigated using normal rats and hypophysectomized rats subjected either to fasting or to streptozotocin-induced diabetes.Growth hormone administration in normals increased animal weight gain and in vitro incorporation of fatty acid into tissue lipids but did not alter fat pad composition or fatty acid oxidation. In diabetic hypophysectomized rats given growth hormone weight gain, fat pad protein content and fatty acid utilization were increased, whereas fat pad lipid content and glucose utilization were decreased. In fasted-hypophysectomized rats growth hormone decreased weight loss and increased adipose tissue protein concentration. Fatty acid oxidation was not altered, whereas incorporation into adipose tissue lipids was increased.

ISSN:1663-2818    

DOI:10.1159/000178309

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

Acetone powder of rat kidney was extracted with0.15 m KCl containing 5 mM tris-Cl and 15% glycerol. The fraction, precipitated by 35-75% saturated ammonium sulfate, was chromatographed on a Biogel P-300 column to obtain a partially purified rat kidney enzyme preparation preferentially hydrolyzing parathyroid hormone. Parathyroid hormone in human serum lost its immunoreactivity after incubation with this rat kidney enzyme preparation according to radioimmunoassay using guinea pig antibody to bovine parathyroid hormone and 125I-labeled highly purified bovine parathyroid hormone. Such activity of destroying PTH immunoreactivity, proportional to the amount of enzyme and duration of incubation, was lost after heating at 60°C for 10 min. The optimum pH, 8.6, and susceptibility to inhibitors such as p-chloromercuribenzoate, monoidoacetate, o-phenanthroline and EDTA were similar to those in the hydrolysis of 125I-PTH

ISSN:1663-2818    

DOI:10.1159/000178310

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

Adrenal cortical tissue implanted into the spleen of adrenalectomized rats regenerated and differentiated into itsstructural zones. Pituitary gland appeared to be necessary forregeneration. Both neutral fat and activities of glucose-6-phosphate-and steroid dehydrogenases were present in the regenerated cortex. The intrasplenic adrenal contained corticosterone and desoxycorticosterone. Presence of desoxycorticosterone in the regenerated cortex probably obviates the saline requirement by these animals.

ISSN:1663-2818    

DOI:10.1159/000178311

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

Mechanisms of homeostasis in a euryhaline amphibian, Rana cancrivora, the crab-eating frog, are reviewed and discus-sed. While plasma osmolality of R. cancrivora is always greater thanthe bathing fluid (from 0 to 800 mOsmole), urine is always dilutewith reference to plasma. Homeostasis is maintained by the factthat the skin, though permeable to water, is insensitive to the actionof neurohypophysial hormones, the potential differences, short circuit current and net influx of Na+ across it being smaller than inother anuran amphibians. The hypertonicity of the plasma when the frog is in saline solutions is achieved by an increase of plasma NaCl and urea concentration. The mechanism by which plasma urea concentration increases from 40 mM when the frog is in fresh water to 400 mM when in brackish water can be explained by an initial diffusion of urea from the bladder, followed by an enhanced activity of the enzymes of the ornithine-urea cycle. Rapid diffusion of urea into muscles protects the latter against damage due to hypertonicity of the plasma and extracellular fluid. Neurohypophysial hormones appear to act mainly on the bladder where they appear to increase the permeability to urea. The gastrointestinal tract does not play a major role in the mechanism of adaptation to hypertonic solutions. The significance of the different mechanisms used by R. cancrivora to maintain homeostasis are discussed in relation to similar problems in other anuran amphibians.

ISSN:1663-2818    

DOI:10.1159/000178312

出版商:S. Karger AG    

年代:1973

数据来源: Karger