Abstract
We investigated the endocrine basis for sexual dimorphism of the sound-producing apparatus (swimbladder and attached sonic muscles) in the oyster toadfish Opsanus tau by implanting steroid pellets in gonadectomized females and males. In females, testosterone and dihydrotestosterone caused, respectively, 32.3 and 31.5% increase (P < 0.0001), and estradiol 17 β caused 11.3% increase (P < 0.0104) in swimbladder weight compared with controls. In males, testosterone caused 17.7% (P < 0.028), dihydrotestosterone 24.0% (P < 0.0008), and estradiol 10.8% (N.S.) increase from controls. Swimbladder weight gains occurred despite the fact that these fish refused food and did not gain weight. In a final experiment on fed females, testosterone and 11-ketotestosterone caused a similar increase (16.6 and 18.9%, respectively) compared with controls. These results indicate that swimbladders in adults of both sexes retain the ability to respond to steroid treatments and suggest that sexual differences in bladder size are controlled without a critical period by hormonal concentrations within the fish.
| Original language | English |
|---|---|
| Pages (from-to) | 289-298 |
| Number of pages | 10 |
| Journal | Experimental Neurology |
| Volume | 92 |
| Issue number | 2 |
| DOIs | |
| State | Published - May 1986 |
Bibliographical note
Funding Information:Abbreviations: SMN-sonic motor nucleus, T-testosterone propionate, DHT-dihydrotestosterone, E-estradiol. ’ We thank Dr. Jennifer Stewart for reviewing the manuscript, Gary Hill for procuring toadfish. and Kathleen A. Drummond for technical assistance. Supported by Virginia Commonwealth University Biomedical Grant-in-Aid and National Institutes of Health grant MH3892 I. Contribution 1292 from the Virginia Institute of Marine Science, The College of William and Mary.
ASJC Scopus subject areas
- Neurology
- Developmental Neuroscience