Sidor C A, Blackburn D G
Department of Organismal Biology and Anatomy, University of Chicago, Illinois 60637, USA.
J Exp Zool. 1998 Jan 1;280(1):28-37. doi: 10.1002/(sici)1097-010x(19980101)280:1<28::aid-jez4>3.0.co;2-j.
In Rana pipiens, forelimb muscles that are used by males to clasp females during amplexus are sexually dimorphic in mass, protein content, and fiber composition. This experiment examined the effects of castration and exogenous testosterone on wet mass, dry mass, and protein content of the 22 major forelimb muscles of male leopard frogs to determine whether established patterns of sexual dimorphism of the muscles are reflected in differential androgen sensitivity. Muscles ranged from highly and moderately responsive to testosterone treatment (e.g., flexors of the elbow and of the carpus; adductors of the shoulder and of the first digit) to nonresponsive to testosterone (antagonists to these muscles). The mean dry mass of the testosterone-responsive muscles ranged broadly from 28-164% over control values. Castration had little or no effect on the response to testosterone, nor did it affect muscle mass in frogs not treated with hormone, as compared to sham-operated animals. Experimental treatment did not alter water content or protein concentration of muscles. The degree of testosterone sensitivity exhibited among the muscles of males closely correlated with their degree of sexual dimorphism. We postulate that androgens influence the functional attributes of male forelimb muscles through both organizational and activational effects.
在北美豹蛙中，雄性在抱对时用于抱紧雌性的前肢肌肉在质量、蛋白质含量和纤维组成上具有两性差异。本实验研究了去势和外源性睾酮对雄性豹蛙22块主要前肢肌肉的湿重、干重和蛋白质含量的影响，以确定肌肉既定的两性差异模式是否反映在雄激素敏感性差异上。肌肉对睾酮处理的反应程度从高度和中度反应（如肘部和腕部的屈肌；肩部和第一指的内收肌）到无反应（这些肌肉的拮抗肌）不等。对睾酮有反应的肌肉的平均干重比对照值高出28% - 164%。与假手术动物相比，去势对睾酮反应几乎没有影响，对未用激素处理的青蛙的肌肉质量也没有影响。实验处理未改变肌肉的含水量或蛋白质浓度。雄性肌肉中表现出的睾酮敏感性程度与其两性差异程度密切相关。我们推测雄激素通过组织和激活作用影响雄性前肢肌肉的功能属性。
