Validation of an enzyme immunoassay for measurement of excreted estrogen and testosterone metabolites in the white-crowned sparrow (Zonotrichia leucophrys oriantha)
Abstract 10.1002/zoo.1430140203.abs Over the past few years there has been a growing interest in hormonal analyses, despite the cost and difficulty involved in measuring hormones using radioimmunoassays. Therefore, there is a need for alternate procedures, such as enzyme immunoassays, capable of providing similar data to that provided by radioactive methods. Enzyme immunoassays are a less […]
Absence of daily cycles in plasma sex steroids in male and female tuatara (Sphenodon punctatus), and the effects of acute capture stress on females
The possible existence of daily cycles in plasma concentrations of sex steroids was examined in wild male and female tuatara (Sphenodon punctatus). Samples were collected from freshly captured animals at dusk, middle of the night, dawn, and middle of the day in January (summer) and July (winter). Males showed daily cycles in mean body temperature […]
Exposure to the steroid hormone 20-hydroxyecdysone modulates agonistic interactions in male Homarus americanus
In this study we present evidence that 20-hydroxyecdysone (20E) affects agonistic behavior in male American lobsters and that male and female animals differ in their response to the hormone. Thirty-minute staged fights were conducted between large males exposed either to artificial seawater (ASW) or 20E and small, anosmic opponents. The nephropores of both combatants were […]