Why does castrated male odor attract sexually active male rats?–Attractivity induced by hypothalamus-pituitary-gonad axis block
| Autor: | Himeka Hayashi, Ryoko Kumagai, Yasuhiko Kondo |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Male
endocrine system medicine.medical_specialty medicine.drug_class Hypothalamus Experimental and Cognitive Psychology Biology Human chorionic gonadotropin Gonadotropin-Releasing Hormone Behavioral Neuroscience Follicle-stimulating hormone Internal medicine medicine Animals Horses Gonads Equine chorionic gonadotropin Estrous cycle luteinizing hormone/choriogonadotropin receptor Luteinizing Hormone Rats Endocrinology Odor Pituitary Gland Odorants Female Follicle Stimulating Hormone Gonadotropin hormones hormone substitutes and hormone antagonists |
| Zdroj: | Physiology & Behavior. 230:113288 |
| ISSN: | 0031-9384 |
| Popis: | Sexually experienced male rats show an olfactory preference for estrous female odor compared to male odor. Notably, they also prefer castrated male over gonadally intact male odor. This study examined the role of elevated circulating gonadotropins and gonadotropin-releasing hormone (GnRH) induced by disinhibition of the hypothalamus-pituitary-gonad axis in the castration-induced attractiveness of male rats. Experiment I compared preference of sexually experienced males between odors of castrated males injected with a GnRH antagonist (Cast+Ant), castrated males injected with saline (Cast), and gonadally intact males (Sham). These olfactory preference tests revealed that probe males significantly preferred Cast over Sham and Cast+Ant odors but had no preference between Sham and Cast+Ant odors. Experiment II used hypophysectomy (HPx) to remove the gonadotropin source in place of pharmacologically antagonizing GnRH. Similarly, the probe males preferred Cast (high both GnRH and gonadotropins) over HPx (high GnRH but no gonadotropin) odors, but also preferred HPx than Sham (low both GnRH and gonadotropins) odors. We then examined the effects of exogenous gonadotropins, human chorionic gonadotropin (hCG) and equine chorionic gonadotropin (eCG), to reveal which gonadotropins critically affect on the attractiveness of HPx males. The olfactory preference tests revealed that injecting eCG, but not hCG, significantly increased the probe males` preference compared to HPx male odor, suggesting that the attractiveness is augmented via follicle stimulating hormone (FSH) receptor rather than luteinizing hormone receptor. These results indicate that sexually active male rats show olfactory preference for castrated male rats due to elevated GnRH and FSH blood levels produced by a lack of androgens. |
| Databáze: | OpenAIRE |
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