Significant Decrease In Testosterone Research Articles

Inhibin secretion is influenced by Ley dig cells: evidence from studies using the cytotoxin ethane dimethane sulphonate (EDS)

Adult male rats given a single intraperitoneal injection of the Leydig cell cytotoxin ethane dimethane sulphonate (EDS) show a significant decrease in testosterone from 7 to 14 days, and elevation of serum FSH and LH levels commencing 7 days after treatment, returning to normal at 28 days for LH and 49 days for FSH. A significant rise in serum inhibin levels was seen at day 14 after EDS treatment with levels returning to normal at day 49. In a second series of experiments, silastic implants of testosterone, either 2.5 cm or 22.5 cm in length, were introduced subcutaneously into adult male rats which were treated with EDS 10 days later. Both doses of testosterone suppressed basal LH levels but did not significantly change FSH levels. The rise in FSH and LH levels seen in normal rats after EDS treatment did not occur in either group of testosterone-implanted rats. However, serum inhibin levels rose significantly in both groups after EDS treatment, suggesting that the rise in serum inhibin levels was not due to stimulation arising from the increase in FSH levels after EDS treatment. The data suggest that the rise in serum inhibin levels after EDS treatment is linked to destruction of the Leydig cells through mechanisms that require further investigation.

Effects of Ascorbic Acid on In Vitro Steroidogenesis in Guinea Pigs

Guinea pig ovarian whole tissue homogenates were incubated with [14C]-labelled cholesterol, pregnenolone, and progesterone. Testicular homogenates were incubated with [14C]-progesterone. All incubations were carried out in the presence of 0, 0.5, 1.0, or 2.0 mm ascorbic acid. The conversion of cholesterol to pregnenolone was significnatly decreased in the 1.5 and 2.0 mm ascorbic acid incubations, resulting in a significant decrease in testosterone and progesterone production. The addition of 0.5 mm ascorbic acid increased the conversion of pregnenolone to Δ4 steroids and decreased its conversion to Δ5 steroids, relative to the other ascorbic acid treatments. The conversion of progesterone to 17A-hydroxyprogesterone was significantly decreased in the presence of 1.5 mm ascorbic acid over the O mm treatment. The data supports a general inhibitory effect of high ascorbic acid on the steroid hydroxylations, and a possible regulatory role of ascorbic acid on the conversion of pregnenolone to Δ4 and Δ5 steroids.L-Ascorbic acid steroidogenesis guinea pig

Effects of caudate nuclei and frontal cortical ablations in cats: Testosterone and 17β-estradiol concentrations

Plasma testosterone and 17β-estradiol concentrations and lordotic behavior were measured in male cats which had received lesions of the caudate nuclei and frontal cortices and were compared with intact and other lesion controls. Only the acaudate cats showed significant increases in lordosis whereas all groups with lesions showed significant decreases in testosterone. Only the afrontal animals showed a significant increase in the concentrations of 17β-estradiol but it was unaccompanied by the behavioral change. It is concluded that the striking changes in lordotic behavior seen in the cats with extensive caudate lesions are most probably due to the increased somatosensory reactivity seen in these animals, rather than to a shift in sex hormone balance.

Regional distribution of steroids in the dog epididymis.

Concentrations of delta 4 androstenedione, testosterone and dihydrotestosterone were measured in the post-nuclear supernatant of the dog epididymis. In addition, they were measured in the efferent ducts and the testis. From the efferent ducts to the corpus there was a significant decrease in testosterone and delta 4 androstenedione concentrations. On the contrary, the concentration of dihydrotestosterone increased from the efferent ducts to the corpus where this steroid predominated. The marked differences in steroid concentration along the epididymis of the dog suggested regional differences in androgen metabolism.