Biology subjects

Soma, K. K.

Publications and source records attributed to Soma, K. K..

3 recordsLinked to original sources

bioRxiv2023

Maternal high-sucrose consumption increases maternal and fetal glucocorticoids and decreases fetal androgens in the rat

Maternal diet has long-term effects on offspring brain development and behavior. Sucrose (table sugar) intakes are high in modern diets, but it is not clear how a maternal high-sucrose diet (HSD) affects the offspring. In rats, a maternal HSD (26% of calories from sucrose, which is human-relevant) alters maternal metabolism and brain and also alters adult offspring endocrinology and behavior in a sex-specific manner. Maternal sucrose intake increases corticosterone levels in adult female offspring and increases motivation for a sugar reward in adult male offspring. Here, to identify possible underlying mechanisms, we examined how a maternal HSD affects steroids in the dam, placenta, and fetus at embryonic day 19.5 using liquid chromatography tandem mass spectrometry. Maternal sucrose intake increased glucocorticoids (11-deoxycorticosterone and 11-dehydrocorticosterone) and tended to increase the mineralocorticoid aldosterone in maternal serum. In the placenta, maternal sucrose intake decreased androstenedione and testosterone. Maternal HSD increased aldosterone in the fetal blood. Similarly, in the fetal brain, maternal high-sucrose intake increased aldosterone in the medial prefrontal cortex and nucleus accumbens, decreased testosterone in the nucleus accumbens, and decreased corticosterone in the orbital cortex. In addition, the 11-dehydrocorticosterone/corticosterone and aldosterone/corticosterone ratios were increased in most examined brain regions. Lastly, maternal HSD increased 11-dehydrocorticosterone and aldosterone in the amniotic fluid. In summary, we found dramatic and widespread changes in maternal, placental, and fetal steroids that might mediate the long-term effects of maternal sucrose consumption on adult offspring neuroendocrinology and behavior.

neuroscience↗

bioRxiv2023

Brain and circulating steroids in an electric fish: relevance for non-breeding aggression

Steroids play a crucial role in modulating brain and behavior. While traditionally it is considered that the brain is a target of peripheral hormones produced in endocrine glands, it has been discovered that the brain itself produces steroids, known as neurosteroids. Neurosteroids can be produced in brain regions involved in the regulation of social behaviors and can act locally regulating behaviors like reproduction and aggression. Here, for the first time in a teleost fish, we used liquid chromatography-tandem mass spectrometry (LC-MS/MS) to quantify a panel of 8 steroids in both plasma and brain. We use the weakly electric fish Gymnotus omarorum, a species which shows non-breeding aggression in both sexes, to characterize these hormonal profiles in wild non-breeding adults. We show that: 1) systemic steroids in the non-breeding season are similar in both sexes, although only males have circulating 11-KT, 2) brain steroid levels are sexually dimorphic, as females display higher levels of AE, T and E1, and only males had 11-KT, 3) systemic androgens such as AE and T in the non-breeding season are potential precursors for neuroestrogen synthesis, and 4) estrogens, which play a key role in non-breeding aggression, are detectable in the brain (but not the plasma) in both sexes. These data fall in line with previous reports in G. omarorum which show that non-breeding aggression is dependent on the estrogenic pathway, as has also been shown in bird and mammal models. Overall, our results constitute a fundamental groundwork to understanding the complexity of hormonal modulation, its potential sex differences, the role of neurosteroids and the interplay between central and peripheral hormones in the regulation of behaviors.

neuroscience↗

bioRxiv2021

Androgen synthesis inhibition but not gonadectomy reduces persistence during strategy set-shifting and reversal learning in male rats

Androgens regulate behavioural flexibility, which is essential to adapt to a changing environment and depends on the medial prefrontal cortex (mPFC). Testosterone (T) administration decreases behavioural flexibility. It is well known that T is produced in the gonads, but T is also produced in the mesocorticolimbic system, which modulates behavioural flexibility. It is unclear how T produced in the brain versus the gonads influences behavioural flexibility. Here, we assess the effects of the androgen synthesis inhibitor abiraterone acetate (ABI) and long-term gonadectomy (GDX) on behavioural flexibility in two paradigms. In Experiment 1, ABI independent of GDX reduced the number of trials to criterion and perseverative errors in a strategy set-shifting task. Similarly, in Experiment 2, ABI but not GDX reduced perseverative errors in a reversal learning task. In subjects from Experiment 1, we also examined tyrosine hydroxylase immunoreactivity (TH-ir), and ABI but not GDX increased TH-ir in the mPFC. Our findings suggest that neurally-produced androgens modulate behavioural flexibility via modification of dopamine signalling in the mesocorticolimbic system. These results suggest novel roles for neurosteroids and possible side effects of ABI treatment for prostate cancer.

neuroscience↗