SOME EFFECTS OF GONADOTROPIC HORMONES ON THE THREESPINE STICKLEBACK, GASTEROSTEUS ACULEATUS

Abstract

Sticklebacks collected during the autumn and maintained under 8-hour daily photoperiods did not mature sexually; their gonads remained in the condition characteristic of late summer and autumn fish in nature and probably did not change after the fish were placed under controlled photoperiods. No stimulation of the gametogenetic and related tissues occurred when these fish were treated with purified mammalian FSH (Armour) but LH (Armour) produced a maturation of all gonads to stages characteristic of late winter and spring fish; with LH, 80% of the individuals attained the stages of sexually mature fish in nature. Chorionic gonadotropins (Organon) also had a stimulatory effect but were considerably less active than the LH; PMS was more effective than HCG. TSH (Parke Davis or Organon) had a marked gonadotropic action as well as the expected thyrotropic effect and stimulated the reproductive organs to about the same degree as the chorionic gonadotropins. Crude extracts of alcohol-preserved salmon pituitaries were only mildly active but stimulated all gonads to stages beyond those normally found in the late summer and autumn.