Posts Tagged ‘Steroidogenesis

Data presented in the current paper clearly establish that testosterone is a primary metabolic product of the medullary/interstitial tissues resulting in elevated plasma concentrations of this steroid. In accordance with the preceding scenario, Gorman and Stone note that, unlike other female insectivores (e.g., shrews), female T. europaea do not increase the size of their territories […]

T europaea is one of four species of the genus Talpa known to have ovotestes. Of interest is how this phenotype could have arisen in the ancestor of the genus Talpa and what advantage this phenotype conveyed in order for it to be conserved in every female of all four of the species examined. Because […]

Similarly, when ovarian production of androstenedione and estradiol is up-regulated during estrus, the secretion of testosterone by the interstitial gland is substantially diminished. It seems paradoxical that steroidogenesis is up-regulated in only one portion of the gonad at any given time. It is possible that the receptors for LH and FSH may be differentially expressed […]

Early histological studies support these data. In a detailed study of the histology of the interstitial gland, Deanesly indicates that the interstitial cells of the anestrous ovotestis are large and glandular and that they contain lipoids, while those from pregnant females are regressing and vacuolated. Also noteworthy in this regard is the similarity of plasma […]

The testis-like histology of the interstitial gland is reflected in its testis-like steroidogenic activity. Circulating levels of testosterone in the reproductively inactive females were exceptionally high for any nonpregnant female mammal: T europaea, 0.79-1.44 ng/ml; spotted hyena, 0.400.50 ng/ml; rhesus monkey, 0.20-0.80 ng/ml; Siberian tiger, 0.20-0.70 ng/ml; rat, 0.16-0.18 ng/ml; rabbit, 0.05-0.10 ng/ml; dog, 0.030-0.7 […]

Similar relative trends were observed when tissue ho-mogenates were incubated with [3H]androstenedione. Interstitial glands from reproductively inactive females metabolized the [3H]androstenedione into predominantly testosterone (Table 3). The ovarian portion from these animals produced significantly less testosterone than the interstitial gland (p < 0.05), and it is possible that contaminating interstitial gland contributed to the testosterone […]

Production of Testosterone In Vitro Interstitial glands from reproductively inactive females metabolized the [14C]progesterone into predominantly testosterone at levels comparable to those observed for the testes from reproductively inactive and active males (Table 2). In contrast, the ovarian portion of the ovotestis from reproductively inactive females converted significantly less of the [14C]progesterone into testosterone (p […]

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