Premium
Effects of Orchidectomy and Testosterone Replacement on Numbers of Kisspeptin‐, Neurokinin B‐, and Dynorphin A‐Immunoreactive Neurones in the Arcuate Nucleus of the Hypothalamus in Obese and Diabetic Rats
Author(s) -
Dudek M.,
Kołodziejski P. A.,
PruszyńskaOszmałek E.,
Ziarniak K.,
Sliwowska J. H.
Publication year - 2017
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1111/jne.12453
Subject(s) - endocrinology , medicine , kisspeptin , neurokinin b , hypothalamus , arcuate nucleus , dynorphin , testosterone (patch) , streptozotocin , dynorphin a , arc (geometry) , diabetes mellitus , neuropeptide , biology , substance p , receptor , opioid peptide , opioid , geometry , mathematics
Neurones expressing kisspeptin, neurokinin B and dynorphin A, located in the arcuate nucleus of the hypothalamus ( ARC ), are important regulators of reproduction. Their functions depend on metabolic and hormonal status. We hypothesised that male rats with high‐fat diet‐induced obesity ( DIO ) and/or streptozotocin‐induced diabetes mellitus type 1 ( DM 1) and type 2 ( DM 2) will have alterations in numbers of immunoreactive (‐IR) cells: kisspeptin‐IR and/or neurokinin B‐IR and dynorphin A‐IR neurones in the ARC in the sham condition. In addition, orchidectomy alone ( ORX ) and with testosterone treatment ( ORX +T) will unmask possible deficits in the response of these neurones in DIO , and/or DM 1 and DM 2 rats. Rats were assigned to four groups: a control (C) and one diabetic group ( DM 1) were fed a regular chow diet, whereas the obese group ( DIO ) and the other diabetic group ( DM 2) were fed a high‐fat diet. To induce diabetes, streptozotocin was injected. After 6 weeks, each group was divided into three subgroups: ORX , ORX +T and sham. After another 2 weeks, metabolic and hormonal profiles were assessed and immunocytochemistry was performed. We found that: (1) under sham conditions: (i) DM 1 and DM 2 animals had higher numbers of kisspeptin‐IR cells than controls and (ii) DM 2 rats had increased numbers of neurokinin B‐IR and dynorphin A‐IR cells compared to C animals; (2) ORX and ORX +T treatments unmasked deficits of the studied neurones in DM 1 and DM 2 but not in DIO animals; and (3) DIO , DM 1 and DM 2 rats had altered metabolic and hormonal profiles, in particular decreased levels of testosterone. We concluded that alterations in numbers of kisspeptin‐IR and neurokinin B‐IR neurones in the ARC and their response to ORX and ORX +T may account for disruptions of metabolic and reproductive functions in diabetic but not in obese rats.