Local regulation of testicular immunoreactive-arginine vasopressin and steroidogenesis by naloxone

Presence in mouse Sertoli cell-conditioned medium of a factor that expresses AVP-like inhibition of steroidogenesis by mouse Leydig cells in long-term culture

The influence of spent medium from immature mouse Sertoli cells (SCM) on testosterone production by purified Leydig cells was investigated and compared to that of AVP, a potent local modulator of Leydig cell steroidogenesis. SCM inhibited in a dose-dependent manner the hCG-stimulated testosterone production, but was ineffective in basal conditions. As is known for AVP, (i) a lag period of 72 h was prerequisite for SCM to inhibit Leydig cell function; (ii) the main effect of SCM was located at a step beyond the receptor-adenylate cyclase system, since the hCG- and 8-bromo-cAMP-stimulated testosterone productions were similarly affected. The possibility that the effect of SCM may be related to AVP-like molecule(s) is also supported by the observations that at maximal concentrations the inhibitory effects of AVP and SCM were not additive and that the inhibition of testosterone production was largely (65%) reversed by the presence of [(beta-mercapto-beta, beta-cyclopentamethylenepropionyl, O-Me-Tyr2,Arg8)-vasopressin], a selective vasopressor antagonist. These data indicate that Sertoli cells produce in vitro potent inhibitory factors of Leydig cell steroidogenesis. They provide additional evidence that one of these bioactive factors has an effect on Leydig cell function similar to that of AVP.

Endogenous opiates: 1993

This paper is the sixteenth installment of our annual review of research concerning the opiate system. It is restricted to papers published during 1993 that concern the behavioral effects of the endogenous opiate peptides, and does not include papers dealing only with their analgesic properties. The specific topics this year include stress; tolerance and dependence; eating; drinking; gastrointestinal, renal, and hepatic function; mental illness and mood; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; electrical-related activity; general activity and locomotion; development; immunological responses; and other behaviors.