Macroeconomics

Biotechnology

Biology

Testosterone (patch)

Endocrinology

Receptor

Economics

Stimulation

Biochemistry

Human chorionic gonadotropin

In vivo

In vitro

Follicle-stimulating hormone

Luteinizing hormone

Leydig cell

Internal medicine

Hormone

Andrology

Medicine

Chemistry

Production (economics)

Gonadotropin

Biochimica et Biophysica Acta (BBA) - General Subjects

Measurement of testosterone production by the rat testis in vitro provides an extremely sensitive response system for the biological activities of luteinizing hormone (LH) and human chorionic gonadotrophin (HCG) activity in vitro. The sensitivity of the response to gonadotrophins depends upon the structural integrity of the isolated testis, as physical disruption by teasing apart the testis tubules results in substantial loss of the steroidogenic response to trophic hormones. The intact testis responds to as little as 0.2 ng HCG or 1 ng ovine LH, and shows maximal stimulation with 2 ng HCG or 10 ng ovine LH. Testosterone production in vitro was also markedly enhanced by Sepharose-coupled ovine LH and by dibutyryl cyclic AMP, consistent with the view that LH acts upon cell-membrane receptors to stimulate steroidogenesis in the testis via activation of adenyl cyclase. Desialylated gonadotrophins retained considerably greater biological activity in vitro than in vivo, indicating that the sialic acid residues are not essential for interaction of gonadotropins with their tissue receptor sites.

Gonadotrophin stimulation of testosterone production by the rat testis in vitro