Gonadotrophin- and Androgen Precursor-Stimulated Testosterone Secretion by Interstitial Cells from Mongolian Gerbil Testes: Influence of Plasma Proteins and Elevated Temperature

Summary

Interstitial cells isolated from Mongolian gerbil testes have been used to investigate the effects of plasma proteins and incubation temperature on HCG- and androgen precursor-stimulated testosterone secretion. Short term (15 min) incubation of interstitial cells with various precursors resulted in a significant increase of testosterone release. On the other hand, no stimulatory effect of HCG (10 mIU) could be observed. Precursor (e.g. progesterone)-stimulated testosterone secretion linearly increased with cell concentrations (0.5x10⁵ to 4.0x10⁵cells/0.7 ml medium, r = <0.99, p < 0.001). In the presence of 50% horse plasma, progesterone-stimulated testosterone secretion was even more pronounced. Similarly, also gerbil, rat, calf or human plasma significantly increased progesterone-stimulated testosterone output. Interestingly, this effect was markedly reduced in the presence of cortisol. While incubation of interstitial cells for 15 min at either 40 ^°C or 42 ^°C had no significant effect on androgen precursor- or HCG-stimulated testosterone secretion, incubation of cells at 44 ^°C resulted in a drastic reduction of HCG-stimulated testosterone release, without affecting progesterone- or DHEA-stimulated testosterone secretion. Taken the simplicity to make interstitial cells unresponsive to HCG into account, heat-treated cells might prove to be a versatile tool to distinguish between HCG- and protein-/androgen precursor-stimulated testosterone secretion in vitro.

Key words

Androgen precursors - Gonadotrophins - Plasma proteins - Temperature - Mongolian gerbil testes - Testosterone secretion in vitro