THE ROLE OF TEMPERATURE IN REGULATING THE SPERMATOGENETIC CYCLE IN THE COMMON FROG (RANA TEMPORARIA)

Abstract

Common frogs (Rana temporaria) were hypophysectomized and then kept at high and low temperatures. All operated animals and many of the controls were injected with gonadotropins of amphibian or mammalian origin. Results were determined quantitatively by measuring the mean diameter of the seminiferous tubules, the spermatogenetic progress by means of the mean developmental stage of the spermatogenetically active cell nests, and the spermatogenetic stimulation by means of the percentage of active cell nests. Results showed that from the end of the spermatogenetic period until January the spermatogenetic cycle was determined by an inherent mechanism which manifested itself through the sensitivity of the primary spermatogonia to gonadotropins, whereas during the rest of the year the environmental temperature was the limiting factor for spermatogenesis, and acted chiefly through the gonadotropin secretion of the adenohypophysis.