Testosterone response in arginine vasopressin desensitized immature rat testis

Direct injection of arginine vasopressin into immature rat testis inhibited basal testosterone synthesis. Simultaneous injection of arginine vasopressin with luteinizing hormone, norepinephrine or cholera toxin inhibited these agonists - induced testosterone response. In arginine vasopressin - desensitized testis, cAMP response to luteinizing hormone, norepinephrine and cholera toxin was not disturbed. However, testosterone response to luteinizing hormone, norepinephrine or cholera toxin was drastically reduced in arginine vasopressin-desensitized testis. This shows that the increased cAMP generated by luteinizing hormone, norepinephrine or cholera toxin in arginine vasopressin desensitized testis did not cause increase in steroidogenesis. This could be due to a lesion in steroidogenic pathway beyond cAMP generation caused by arginine vasopressin.