Experimental elevation of wildlife testosterone using silastic tube implants.
Testosterone (T) is a key androgen that mediates vertebrate molecular, cellular, and behavioral processes. Its manipulation is therefore of interest to a vast number of researchers studying animal behavior and reproduction, among others. Here, the usage of silastic implants across wildlife species is reviewed, and a method to manipulate rock hyrax (Procavia capensis) testosterone levels using silastic implants is presented. Using a series of in-vitro and in-vivo experiments, the secretion patterns of silastic tubes and silastic glue were tested and were surprisingly found to be similar. In addition, we studied endogenous T levels in wild-captured rock hyraxes (Procavia capensis), and using T implants succeeded in elevating T to the maximal physiological concentrations recorded during the mating period. The number of implants that were inserted was the only predictor of T levels, and seven 20mm implants were found to be the optimal dose. Implants induced sexual behaviors in the non-reproductive period. The duration of time that the implants were in the hyrax was the only significant factor that influenced the amount of T left over in the implant once it was removed. All together we affirm that T implants may offer a versatile tool for wildlife behavioral research by elevating T levels in the non-breeding period to maximal breeding levels.
Faculty of Life Sciences, Bar Ilan University, Ramat-Gan 5290002, Israel; School of Veterinary Medicine, Hebrew University, Rehovot, Israel.
Efrat
E
Koresh
Faculty of Life Sciences, Bar Ilan University, Ramat-Gan 5290002, Israel.
Devorah
D
Matas
Faculty of Life Sciences, Bar Ilan University, Ramat-Gan 5290002, Israel. Electronic address: Lee.Koren@biu.ac.il.
Lee
L
Koren
D000269:Adhesives; D000728:Androgens / Q000008:administration & dosage*; D000818:Animals; D000835:Animals, Wild / Q000502:physiology / Q000601:surgery; D001522:Behavior, Animal; D003692:Delayed-Action Preparations / Q000493:pharmacokinetics; D004343:Drug Implants; D005260:Female; D007043:Hyraxes / Q000502:physiology* / Q000601:surgery; D007440:Intubation / Q000295:instrumentation / Q000662:veterinary*; D007557:Israel; D008297:Male; D012098:Reproduction; D012826:Silicone Elastomers; D013739:Testosterone / Q000008:administration & dosage*
D000269:Adhesives; D000728:Androgens; D003692:Delayed-Action Preparations; D004343:Drug Implants; D012826:Silicone Elastomers; D013739:Testosterone
Implants; Method; Procavia capensis; Rock hyrax; Testosterone