The effects of follicle-stimulating hormone and luteinizing hormone on the testis of hypophysectomized frogs ( Rana temporaria)

Abstract

1. 1. Hypophysectomy of frogs during the spermiation period prevents spermiation and causes an accumulation of cholesterol-positive lipids in the Sertoli cells. It has apparently little effect on the spermatogenetic condition, but primary spermatogonia seem to lose their mitotic capacity. 2. 2. If hypophysectomy is followed by daily injections of purified LH, spermiation is induced but Sertoli cells still become lipoidal and cholesterol-positive, and there is no stimulation of the primary spermatogonia. Interstitial cells, on the other hand, are markedly affected and become densely lipoidal and cholesterol-positive. 3. 3. Injections of purified FSH after hypophysectomy do not induce spermiation or stimulate the interstitial Leydig cells, but cause the disappearance of lipid droplets from the Sertoli cell cytoplasm and stimulate spermatogenesis. 4. 4. In May, the sequence of events following hypophysectomy closely parallels the changes that take place in the testes of intact controls at this time of year. This includes a buildup of dense, cholesterol-positive lipid within the seminiferous tubules. In both, spermatogonia undergo mitosis, but the resulting germ cells never mature into spermatocytes, and degenerate. 5. 5. In normal frogs, spermatogenesis restarts in July and is accompanied by the disappearance of the intratubular lipids and cholesterol. In hypophysectomized frogs, however, spermatogenesis does not take place and tubule lipids remain as a dense amorphous mass filling the tubules. 6. 6. Administration of LH into these hypophysectomized frogs has little effect on the tubules but stimulates the interstitium, but FSH injections produce a clearance of the intratubular lipid, accompanied by a recrudescence of spermatogenesis. 7. 7. The possibility that the seasonal lipid cycle in the testes of normal frogs forms the basis of the seasonal changes in the sensitivity of the germinal epithelium to gonadotrophins is discussed.