## Abstract Neutral, organic molecules with seven or less major atoms permeate erythrocytes of the little skate (__Raja erinacea__.) Hypotonicity (80%) increased permeation up to 10βfold. Under both isotonic and hypotonic conditions solute influx occurred with the same size limitation, indicating t
Mechanisms of ammonia and acid extrusion by the little skate,Raja erinacea
β Scribed by Evans, David H. ;Kormanik, Gregg A. ;Krasny, Edward J.
- Publisher
- John Wiley and Sons
- Year
- 1979
- Tongue
- English
- Weight
- 288 KB
- Volume
- 208
- Category
- Article
- ISSN
- 0022-104X
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β¦ Synopsis
Abstract
The little skate (Raja erinacea) excretes ammonia and titratable acid at a rate of 6.37 and 40β95 ΞΌM. 100gβ1. hrβ1, respectively, at an external pH of 7.8 to 8.0. Transfer into Naβ and Kβfree artifical sea water does not alter the rate of ammonia efflux but reduces titratable acid efflux to zero. Addition of amiloride (10β4M) to the external sea water does not alter the ammonia efflux but reduces the titratable acid efflux by 49%. Thus, while ammonia efflux is apparently not via Na (or K)/NH4 exchange, excretion of titratable acid is apparently via Na (or K)/H exchange.
π SIMILAR VOLUMES
The pathway of p-alanine (BALA) oxidation was examined in the liver of the little skate, Raja erinacea. BALA oxidation in liver slices was reduced by inhibitors of transamination and mitochondria1 electron transport. Experiments with liver homogenates indicated that BALA was oxidized by a twostep pr
Conventional classification of reproductive modes in female elasmobranchs fails to account for the diversity in ovarian dynamics that operate during oviparous and viviparous cycles. Delineating this diversity is crucial for understanding the endocrine regulation of the manifold physiological mechani
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