Functional sex reversal of all-female nigorobuna Carassius carassius grandoculis to phenotypic males was examined by immersion exposure of fry to 17-methyltestosterone (17-MT) and controlled water temperature during early development. Fry were reared in water containing different concentrations of 17-MT at 24 and 30°C for 80 days starting 20 days after hatching. Although the fish exposed to 0.1...

17α-Methyltestosterone (MT) is widely used in fish hatcheries of many countries to produce male monosex populations. Its genotoxic risk to fish species is not well known and studies in other in vivo models are still inconclusive. MT was tested for genotoxicity in the fish species Oreochromis niloticus (tilapia), a target species, and Astyanax bimaculatus (lambari), a native non-target species. ...

INTRODUCTION Recent research on the impact of testosterone (T) on female sexual function has yielded inconsistent results, and few studies have used physiological measures of genital arousal. AIM This study examined the effects of an acute dose of methyltestosterone (MT) on physiological (genital) and subjective sexual response in postmenopausal women. MAIN OUTCOME MEASURES Vaginal pulse am...

Short-term effects of methyltestosterone (MT) on the endocrine system of adult male zebrafish (Danio rerio) were examined. Males were exposed to 0, 4.5, 6.6, 8.5, 19.8, 35.9, 62.3 ng MT/l and ethinylestradiol (EE2) (26.4 ng/l) for 7 days. Several physiological endpoints that may be affected by endocrine disrupters were analysed, specifically vitellogenin (VTG) concentration, estradiol (E2), tes...

Sex reversal of newly hatched tilapia generally is accomplished via oral administration of 17α-methyltestosterone (MT), which has been incorporated into a starter fish feed at 60 mg MT/kg feed (Popma and Green, 1990). Although the use of the 60 mg MT/kg feed dose consistently yields populations comprised of less than 5% females (i.e., > 95% males), this has not been shown to be the optimal dose...

Sexual size dimorphism is the consequence of differential expression of sex-biased genes related to feeding and growth. Leptin is known to regulate energy balance by regulating food intake. In order to investigate the molecular mechanism of sexual size dimorphism in yellow catfish (Pelteobagrus fulvidraco), the expression of leptin (lep) and its functional receptor (lepr) were detected during l...

One of the most common techniques for producing mono-sex populations is steroid-induced sex inversion. This involves the administration of synthetic androgens (to produce male populations) or estrogens (to produce female populations). Several methods of steroid administration are possible, including injection, microencapsulation, feeding of steroid, and immersion of fry in steroid solutions. Th...