Abstract
Results are presented here which demonstrate that the rates of [14C]acetate incorporation into cholesterol and dolichol increased 4- to 5-fold as mouse spermatocytes matured from the preleptotene to prepuberal pachytene stages. The rate of acetate incorporation into cholesterol then decreased in late pachynema, remained low at all subsequent stages of meiosis, and was very low in mature sperm. In contrast, the rate of acetate incorporation into dolichol remained elevated in late pachytene spermatocytes and round spermatids, then decreased and remained low in mature sperm. The ratio of the rate of [14C]acetate incorporation into dolichol to the rate of incorporation into cholesterol increased during late meiotic prophase and remained high in round spermatids; this altered ratio is further evidence of independent regulation of dolichol and cholesterol synthesis in testes. It was shown previously that normal adult mouse testes incorporated acetate into dolichol at a much higher rate (1.8 to 2.4% of the rate of incorporation into cholesterol) than did testes from sterile W/Wv mice (0.02%) or X-irradiated mice (0.24%). This high rate of acetate incorporation into dolichol in adult testes is now attributed to differentiating spermatocytes, with particularly high rates being observed during pachynema.
Highlights
Results are presented here which demonstrate that pathways was observed in mouse liver(8). the the ratesof [“Clacetate incorporation into cholesterol rates of dolichol and cholesterol synthesis in L cells and liver and dolichol increased4- to 5-foldas mouse spermato- are controlled by one regulatory enzyme, there is some degree cytes maturedfromthepreleptotenetoprepuberal of independent regulation
The results presented here demonstrate that the high rate of dolichol synthesis in normal testes can be attributed to pachytene
Prepuberal pachytene cells incorporated more acetate into cholesterol than did preleptotene and leptotene/zygotene cells, when the data are expressed as disintegrations per min per 4 h perlo6cells; the ratesof incorporation decreased as the cells matured from pachytene spermatocytes to spermatozoa
Summary
(Received for publication, December 29,1980, and in revised form, March 20, 1981). Jane E. Was 20- to 72-fold greater than that observed in mouse liver that normal adult mouse testes incorporated acetate and L-cell cultures. The high rate of dolichol synthesis in (0.24%).This highrate of acetateincorporationinto mouse testes appeared to be due to the presence of differendolichol in adult testes is attributed to differen- tiating spermatogenic cells. The enriched Krebs-Ringer buffer containing added glucose and amino acids usually used for mouse spermatogenic cells (13)was not used here because it significantly lowered incorporation ["Cl-Acerate of [14C]acetate,presumably by decreasing the specific activity of the intracellular acetate pool. Testes from 10adult mice were incubated in 10ml of Krebs-Ringer supernetant Cells (Enriched Leydig Cells) buffer medium containing 800 pCi of [14C]acetate. All testes were washed three times by gravity sedimentation in enriched KrebsRinger buffer Testes washed free of exogenous [I4C]acetatewere first incubated in 0.5 m g / d of collagenase for 12 to 15 min at 33 "Cin enriched KrebsRinger buffer maintained at pH 7.5 on an oscillating shaker at UNIT GRAVITK SEDIMENTATION
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