The Effect Of Adrenal Hormones On Plasma Electrolyte Levels In Thamnophis Sirtalis After Bufo Marinus Parotoid Venom Ingestion

Date of Graduation

Summer 1973


Master of Science in Biology



Committee Chair

Robert Wilkinson


In this study different combinations of adrenal hormones were given to bilaterally adrenalectomized Thamnophis sirtalis. Plasma electrolyte levels were measured before and after adrenalectomy and after force feeding a standard dose of Bufo marinus parotoid gland hemogenate to determine the importance of the adrenal hormones in counteracting the electrolyte disturbance caused by the venom. Survival times were also recorded to determine the effect adrenal hormone replacement had on the survival of the animals. The relative survival time of different groups of animals varied depending on the type of hormone replacement given. Sodium, potassium and calcium levels in the blood plasma were examined before and after adrenalectomy. There was no significant difference between the sodium, potassium or calcium levels in any of the groups when measured before adrenalectomy and 48 hours after. The parotoid venom of Bufo marinus causes several physiological disturbances in Thamnophis sirtalis. Wollard (1971) reported these changes to be decreased heart rate, altered electrocardiograph patterns, changes in electrolyte levels, and respiratory failure. He reported that adrenalectomy enhanced these disturbances. This study shows that ingestion of a dosage of parotoid venom which caused no significant changes in electrolyte levels in intact Thamnophis sirtalis elicited hyperkalemia and hyponatremia in adrenalectomized animals. A careful consideration of the data indicated that pharmacological dosages of glucocorticoids are able to counteract the characteristic electrolyte imbalance which results from Bufo marinus parotoid venom ingestion. They also have a capacity for extending survival time.

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© James D Early