Meeting Abstract
Physiologists often use testosterone propionate (TP) to generate long-term elevations of testosterone (T) because TP has a much longer half-life within the body than T and thus, may exert stronger, more long-lasting effects. Our work, however, indicates that T and TP cannot necessarily be used interchangeably when conducting studies aiming to test the impacts of T on animal physiology and behavior. We implanted laying hens with silastic implants (1/4 inch, ½ inch, and 1 inch long) containing either TP or T. Even the smallest implant size containing TP resulted in complete disruption of egg-laying while the same size implant containing T did not. Larger implant sizes containing TP caused complete ovarian regression within days of implantation and masculinization of behaviors and comb sizes for months after implantation. Our work suggests that while many studies use TP in place of T for studies on animal physiology and behavior, we need to know more about how it interacts with receptors, how long it takes to break down in the body, and how it may impact wildlife in the long-term, particularly in cases where reproductive output is not being measured and thus cannot act as an indicator of the potential detrimental effects associated with TP.
