Steroidogenesis

Sex steroids are known to be synthesized largely in the gonads, but may be produced to a lesser degree in the adrenals and perhaps also in the brain. All sex steroids are derived from cholesterol, and the class of steroid produced depends on the presence of enzymes that catalyze the conversion of one steroid into another. Steroid synthesis can be studied, therefore, by examining the presence in cells or tissues of the steroidogenic or steroid metabolic enzymes. We use a variety of techniques to look for these enzymes, including by examining gene expression, immunoreactive protein or catabolic activity. We look at the gonads, adrenals and brain. We study the role of steroids a) in brain sexual differentiation by examining steroidogenesis in developing zebra finches; b) in the activation of adult behavior by examining steroidogenesis in zebra finches, non-breeding song sparrows (in collaboration with John Wingfield) and, soon, in a tropical antbird (in collaboration with Michaela Hau).