Showing papers on "Bufo melanostictus published in 1970"

Effect of neurohypophysial hormones on fluid movement across isolated bladder of Rana cancrivora, Rana temporaria and Bufo melanostictus

Abstract: 1. The rate of fluid movement across the wall of isolated amphibian urinary bladder was estimated using hemi-bladders of the tropical euryhaline Rana cancrivora, the temperate R. temporaria and the tropical Bufo melanostictus. 2. The rate of water outflow across the bladder walls was: Rana cancrivora, 4·8 μl./cm2.hr; R. temporaria, 7·2 μl./cm2.hr; Bufo melanostictus, 3·7 μl./cm2.hr. 3. When neurohypophysial peptides were added to the serosal solution the rates of water outflow were increased; dose—response curves were prepared relating the augmented rate of fluid movement to the concentration in the bathing fluid of vasopressin, oxytocin or vasotocin. 4. The potencies of the peptides in respect of bladders of each species were: Vasopressin, B. melanostictus:Rana temporaria:R. cancrivora, 500:20:1. Oxytocin, R. temporaria:B. melanostictus:Rana cancrivora, 100:5:1. 5. The ratio of sensitivity of the bladder of each species to the presence of the different peptides was: R. cancrivora, vasotocin:oxytocin:vasopressin, 1000:5:1. R. temporaria, oxytocin:vasopressin, 15:1. Bufo melanostictus, oxytocin:vasopressin, 1:30. 6. The effect of extract of the pituitary gland of Rana cancrivora was examined on R. cancrivora bladder. It had a dose—response curve similar to the dose—response curve of vasotocin. 7. The vasotocin content of the pituitary gland of R. cancrivora was estimated (a) from the dose—response curves using R. cancrivora bladder, (b) by a three-point assay using R. cancrivora bladder and (c) by its effect on water uptake across the skin of Bufo melanostictus. One pituitary gland of Rana cancrivora was found to contain about 0·1 μg vasotocin. 8. The urinary bladder of R. cancrivora was less responsive to neurohypophysial peptides than the bladder of R. temporaria or Bufo melanostictus. 9. The hormonal content of the pituitary gland of Rana cancrivora was smaller than that found in other amphibians.

Compensatory hypertrophy of the contralateral testis after unilateral castration in the toad,Bufo melanostictus (Schn)

Abstract: Nachweis kompensatorischen Wachstums des nach einseitiger Kastration verbleibenden Hodens bei indischer Krotenart (Bufo melanostictus (Schn)). Zunahme von Gewicht, Grosse und Spermienzahl.

Relaxant effect of prostaglandin E 1 on the isolated intestine of the toad (Bufo melanostictus).

Abstract: The pharmacological actions of prostaglandins E1, F1α, E2 and A1 were studied on the longitudinal and circular muscles of the isolated small intestine of the toad. Prostaglandin E1 caused relaxation, whereas prostaglandin A1 was inactive and prostaglandins F1α and E2 caused contractions. Other substances which relaxed the toad intestine were adrenaline, noradrenaline and isoprenaline. On a molar basis, prostaglandin E1 was seven times less potent than isoprenaline, but it was three times more potent than adrenaline and seventeen times more potent than noradrenaline. Phentolamine and propranolol blocked the relaxant effects of catecholamines in concentrations which did not alter the relaxant effect of prostaglandin E1. The results suggested that prostaglandin E1 acted directly on the intestinal smooth muscle of the toad rather than by the local release of catecholamines.