D-Aspartic acid (D-Asp) and nitric oxide (NO) are two biologically active molecules playing important functions as neurotransmitters and neuromodulators of nerve impulse and as regulators of hormone production by endocrine organs. We studied the occurrence of D-Asp and NO as well as their effects on testosterone synthesis in the testis of boar. This model was chosen for our investigations because it contains more Leydig cells than other mammals. Indirect immunofluorescence applied to cryostat sections was used to evaluate the co-localization of D-Asp and of the enzyme nitric oxide synthase (NOS) in the same Leydig cells. D-Asp and NOS often co-existed in the same Leydig cells and were found, separately, in many other testicular cytotypes. D-Asp level was dosed by an enzymatic method performed on boar testis extracts and was 40+/- nmol/g of fresh tissue. NO measurement was carried out using a biochemical method by NOS activity determination and expressed as quantity of nitrites produced: it was +/- nmol/mg of tissue. The effects of the two molecules on steroid hormone production were evaluated by incubating testis homogenates, respectively with or without D-Asp and/or the NO-donor L-arginine (L-Arg). After incubation, the testosterone presence was measured by immunoenzymatic assay (EIA). These in vitro experiments showed that the addition of D-Asp to incubated testicular homogenates significantly increased testosterone concentration, whereas the addition of L-Arg decreased the hormone production. Moreover, the inclusion of L-Arg to an incubation medium of testicular homogenates with added D-Asp, completely inhibited the stimulating effects of this enantiomer. Our results suggest an autocrine action of both D-Asp and NO on the steroidogenetic activity of the Leydig cell.
I was a ketogenic/no carb dieter for several years. I lost 102 lbs in 2004 (and was ‘too skinny’ from others pov’s) and kept it off by only eating no carb foods for 8 years. I fell off the wagon 18 months ago and have gained back 75 lbs. I got back on the wagon 27 days ago and am down lbs already. I’m walking a lot too. 3 miles, or 1 hour, every morning before breakfast to help burn the fat before breaking the fast. My biggest question that I just can not find an answer to, because every place I go to contradicts the other, is about muscle loss – Why do they call it muscle loss? it’s not the muscle tissue that’s going anywhere, it’s the glycogen and water in the muscles. So what’s the big deal? All I really want to know is if I’m doing myself any favors with the power walking twice/day, or am I actually hurt myself. Common sense tells me it’s good for my muscles to get them working hard like I am, after having been sedentary for more than a year, and it’s good for the fat burning process as well. Am I right? or am I wrong???