A radioimmunoassay for dehydroepiandrosterone sulfate in the circulation of rhesus monkeys

Abstract

A radioimmunoassay for dehydroepiandrosterone sulfate (DHAS) was established and validated for use in the rhesus monkey. The validation demonstrated the co-migration of immunoreactive material with tritiated dehydroepiandrosterone after hydrolysis and indicated the absence of other interfering steroids in the measurement. The application of this assay to perinatal samples verified that there are microgram quantities of DHAS present in the circulation. The measurement of circulating concentrations of DHAS in male and female rhesus monkeys at different stages of development demonstrated the absence of increases associated with puberty in this macaque species. Concentrations of DHAS were similar in adult males and females, but were elevated in pregnant females (p<0.05). Adult males had increased DHAS concentrations after GnRH administration (p<0.05), but no change was detected in infant male monkeys. Cortisol and DHAS responses of both infant and adult males occurred at a similar dose of ACTH (0.05 mU per kg versus 0.015 mU per kg, infant and adult, respectively). These data demonstrate the validity of the DHAS measurement in the rhesus monkey and suggest that the secretion of DHAS from infant and adult adrenals is generated by a similar stimulus. Since there was no evidence of gonadal secretion of DHAS in the infant, changes in either adrenal secretion and/or metabolic clearance of DHAS probably account for the microgram concentrations found during the perinatal period.