METABOLIC CHANGES IN TESTICULAR CELLS FROM RATS AFTER LONG-TERM EXPOSURE TO 37 °C IN VIVO OR IN VITRO

Abstract
Biochemical properties of isolated Leydig cells, Sertoli cells and spermatocytes from rat testes have been investigated after in-vivo or in-vitro exposure of these cells to abdominal temperature (37 °C). The rate of production of testosterone and pregnenolone by isolated Leydig cells from cryptorchid and normal testes from mature rats was not different. Production of pregnenolone by mitochondria prepared from cryptorchid testes was 6·7 times higher than production by mitochondria from normal testes. Sertoli cells prepared from immature rats and incubated in vitro at 32 or 37 °C showed, on day 1 of the culture period, an initial twofold increase in the secretion of androgen-binding protein which was absent after 6 days in culture. In contrast, incorporation of [3H]leucine into secreted proteins was stimulated twofold on day 1 as well as by day 6 of culture. Secretion of oestradiol was increased 30-fold by day 6 when compared with the level found on day 1 when cells had been cultured at 37 °C and the increased secretion of oestradiol was maintained for approximately 2 days when the temperature of incubation was decreased to 32 °C Spermatocytes isolated from seminiferous tubules incubated for 20 h at 37 °C were active in the synthesis of RNA. No degeneration of these cells was observed in testes of 25-day-old rats 5 days after experimental cryptorchidism, whereas under similar conditions massive degeneration of spermatocytes was shown in the testes of mature rats. These results suggest that the effects of temperature on the different testicular cells greatly depend on the experimental conditions used to study the effect of temperature.