Figure 3

Functional involvement of sst2A receptor in the regulation of basal (A) and hCG-stimulated (B, C) testosterone secretion by immature porcine Leydig cells pretreated (A, C) or not (A, B) with testosterone. (A) Leydig cells were pretreated (48 h) in the absence of 150 ng/ml testosterone ("-T") or in its presence ("+T"). After 3 rounds of successive washings / incubations (1 h, 32 C), cells were incubated for the additional 3 h in the absence or in the presence of octreotide in the concentration range from 1 pM to 1 μM. At the end of the incubation period cell supernatans were collected for RIA determination of the secreted testosterone. *: p < 0.05 for testosterone secretion measured in the presence of the octreotide compared to that measured in its absence in testosterone pretreated group. b: p < 0.01; c: p < 0.001 for comparisons between testosterone-pretreated and testosterone-untreated cells at a given octreotide concentration. (B) Leydig cells were incubated (3 h) in the presence of the increasing concentrations of hCG (0.065–4 ng/ml range) and either in the absence ("-oct") or in the presence ("+oct") of 1 μM octreotide. Testosterone secretion was measured by RIA in the relevant supernatants. *: p < 0.05; **: p < 0.01 for hCG-stimulated testosterone secretion versus that measured in its absence. a: p < 0.05 for comparisons between octreotide-treated and untreated cells at a given octreotide concentration. (C) Leydig cells were pretreated with testosterone (150 ng / ml, 48 h), then washed as in (A) and incubated for additional 3 h in the presence of the increasing concentrations of hCG (0.065–4 ng/ml range) and either in the absence ("-oct") or in the presence ("+oct") of 1 μM octreotide. Testosterone secretion was measured by RIA in the relevant supernatants. *: p < 0.05; **: p < 0.01 for hCG-stimulated testosterone secretion versus that measured in its absence. c: p < 0.001 for comparisons between octreotide-treated and untreated cells at a given hCG concentration.