Interactions between Testicular Serotoninergic, Catecholaminergic, and Corticotropin-Releasing Hormone Systems Modulating cAMP and Testosterone Production in the Golden Hamster

• Published in: Neuroendocrinology Vol. 76; no. 1; pp. 35 - 46
• Main Authors: Frungieri, Mónica B., Zitta, Karina, Pignataro, Omar P., Gonzalez-Calvar, Silvia I., Calandra, Ricardo S.
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland S. Karger AG 01.07.2002
• Subjects: Animals; Bucladesine - pharmacology; Catecholamines - physiology; Chorionic Gonadotropin - pharmacology; Corticotropin-Releasing Hormone - antagonists & inhibitors; Corticotropin-Releasing Hormone - pharmacology; Corticotropin-Releasing Hormone - physiology; Cricetinae; Cyclic AMP - biosynthesis; Drug Interactions; Epinephrine - pharmacology; Gonadal Steroids: Central Effects and Neurotransmitter Regulation; Immunohistochemistry; Leydig Cells - metabolism; Male; Mesocricetus; Norepinephrine - pharmacology; Peptide Fragments - pharmacology; Photoperiod; Receptor, Serotonin, 5-HT2A; Receptors, Adrenergic, alpha-1 - physiology; Receptors, Adrenergic, beta-1 - physiology; Receptors, Serotonin - physiology; Serotonin - analysis; Serotonin - pharmacology; Serotonin - physiology; Serotonin Antagonists - pharmacology; Testis - chemistry; Testis - drug effects; Testis - metabolism; Testosterone - biosynthesis; Tryptophan Hydroxylase - analysis; Testis; Serotonin agonists; Serotonin; Immunocytochemistry; Catecholamines; Steroidogenesis; Corticotropin-releasing hormone; Gonadal steroids; Hamster; Serotonin antagonists
• ISSN: 0028-3835; 1423-0194
• DOI: 10.1159/000063682

We previously reported the presence of serotonin (5-HT) in testes from golden hamster, a photoperiodic species which is a useful model for the study of states of male (in)fertility. The aims of this study were to investigate: (1) the presence of intrinsic sources of 5-HT in the testis; (2) the role of 5-HT in in vitro androgen production; (3) the serotoninergic receptor subtypes in the testis, and (4) the existence of interactions among the 5-HT receptors and the testicular catecholaminergic and corticotropin-releasing hormone (CRH) systems. Immunohistochemical studies revealed the presence of tryptophan hydroxylase, a 5-HT-biosynthetic enzyme, in interstitial cells which show the characteristic punctate chromatin pattern of Leydig cells. We describe an inhibitory action of 5-HT on testosterone, dihydrotestosterone, and androstane-3α,17β-diol production from testes of peripubertal and adult hamsters maintained in a long photoperiod (14/10 h light/dark), and adult animals exposed to a short photoperiod (6/18 h light/dark). By using several agonists and antagonists of 5-HT receptors, we characterized 5-HT 1A and 5-HT 2A receptor subtypes involved in the inhibitory action of this neurotransmitter on human chorionic gonadotropin stimulated cyclic adenosine monophosphate and testosterone production. CRH also produced a negative modulation of both parameters, but epinephrine and norepinephrine, through α 1 /β 1 -adrenergic receptors, exerted a stimulatory action. 5-HT 1A , 5-HT 2 , and CRH antagonists showed that the testicular activity of the serotoninergic system, but also the α 1 /β 1 -adrenergic receptor system, is mediated by CRH. Moreover, interactions between the 5-HT 2A receptor system and α 1 /β-adrenergic receptors have been established. Thus, these data suggest that α 1 /β 1 -adrenergic receptors are involved in the local regulatory action exerted by 5-HT on steroidogenesis through a 5-HT 2 -receptor-mediated response and the CRH system.