In vitro stimulation of adenosine 3',5'-monophosphate in unilateral undescended testes of humans by follicle-stimulating hormone and luteinizing hormone.

The in vitro effects of FSH and LH on cAMP generation by unilateral undescended testes and contralateral descended testes were investigated. Biopsy tissue was preincubated at 37 C for 5 min in 1 ml Krebs-Ringer bicarbonate buffer (KRB) containing 10 mM aminophylline. Half of each specimen was frozen in liquid nitrogen to assess basal levels of cAMP. The other half was incubated for 20 min at 37 C in 1 ml fresh KRB containing aminophylline and FSH (10 microgram) or LH (10 microgram). The mean concentration of cAMP in the descended testes was 1.03 +/- 0.04 pmol/mg protein, whereas in the undescended testes the level was 1.98 +/- 0.07 pmol/mg protein (P less than or equal to 0.01). After the 20-min incubation period with FSH the concentrations of cAMP in the descended and undescended testes were 10.85 +/- 0.86 pmol/mg protein and 11.21 +/- 1.1 mol/mg protein, respectively. Incubation with LH resulted in the generation of equivalent levels of cAMP in both the descended (2.76 +/- 0.30 pmol/mg protein) and undescended (3.0 +/- 0.17 pmol/mg protein) testes. Although marked histological differences were observed in the germinal epithelium, the appearance and numbers of Leydig and Sertoli cells were comparable. The data suggest that the Sertoli cell is the primary receptor for FSH. Leydig and Sertoli cell functions of the undescended testes, at least in terms of cAMP generation, are similar to normal descended testes.