Interactions between testicular serotoninergic, catecholaminergic, and corticotropin-releasing hormone systems modulating cAMP and testosterone production in the golden hamster.
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-3alpha,17beta-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-HT1A and 5-HT2A 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 alpha1/beta1-adrenergic receptors, exerted a stimulatory action. 5-HT1A, 5-HT2, and CRH antagonists showed that the testicular activity of the serotoninergic system, but also the alpha1/beta1-adrenergic receptor system, is mediated by CRH. Moreover, interactions between the 5-HT2A receptor system and alpha1/beta-adrenergic receptors have been established. Thus, these data suggest that alpha1/beta1-adrenergic receptors are involved in the local regulatory action exerted by 5-HT on steroidogenesis through a 5-HT2-receptor-mediated response and the CRH system.
Frungieri
Mónica B
MB
Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina.
Zitta
Karina
K
Pignataro
Omar P
OP
Gonzalez-Calvar
Silvia I
SI
Calandra
Ricardo S
RS
D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002395:Catecholamines / Q000502:physiology*; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D003346:Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors / Q000494:pharmacology / Q000502:physiology*; D006224:Cricetinae; D000242:Cyclic AMP / Q000096:biosynthesis*; D004347:Drug Interactions; D004837:Epinephrine / Q000494:pharmacology; D007150:Immunohistochemistry; D007985:Leydig Cells / Q000378:metabolism; D008297:Male; D008647:Mesocricetus; D009638:Norepinephrine / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology; D017440:Photoperiod; D044402:Receptor, Serotonin, 5-HT2A; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology; D018342:Receptors, Adrenergic, beta-1 / Q000502:physiology; D011985:Receptors, Serotonin / Q000502:physiology; D012701:Serotonin / Q000032:analysis / Q000494:pharmacology / Q000502:physiology*; D012702:Serotonin Antagonists / Q000494:pharmacology; D013737:Testis / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D013739:Testosterone / Q000096:biosynthesis*; D014365:Tryptophan Hydroxylase / Q000032:analysis
D002395:Catecholamines; D006063:Chorionic Gonadotropin; D010446:Peptide Fragments; D044402:Receptor, Serotonin, 5-HT2A; D018340:Receptors, Adrenergic, alpha-1; D018342:Receptors, Adrenergic, beta-1; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D012701:Serotonin; D013739:Testosterone; D003994:Bucladesine; D003346:Corticotropin-Releasing Hormone; C045089:corticotropin releasing hormone (9-41); D000242:Cyclic AMP; D014365:Tryptophan Hydroxylase; D009638:Norepinephrine; D004837:Epinephrine