Structure and cytophysiology of gastric endocrine gland cells after repeated administration of testosterone propionate

By means of light, electron microscopy and morphometry methods contents and structural organization of endocrinocytes have been investigated in gastric glands of rats, to whom testosterone propionate has been injected for 5, 10, 15, 20 days. The hormone produces certain stimulating effect on the endocrine apparatus function. During the first stages of the experiment most of the endocrinocytes are at the state of active secretion; this is testified as a decreasing composition of histochemically revealed cells in epithelium and their degranulation. During the following stages the process of synthesis is activated in the cells and their amount increases. Appearance of numerous agranular, poorly differentiated endocrinocytes and exo-endocrine cells demonstrates certain intensification of cytogenesis of endocrinocytes in the gastric epithelium. The changes observed are considered as adaptive, directed to stabilize homeostasis, when the hormonal balance is disturbed.     

Effect of injections of testosterone propionate on dominance relationships in a group of cows

In a group of eight heifers, four animals whose social ranks were 2, 4, 6, and 8 were injected with testosterone propionate for 70 days. They all became dominant over controls and did not modify their own relationships among themselves. This experiment was replicated 3 months after the end of the first treatment with the same group; animals whose ranks were 2, 4, 6, and 8 at the beginning of the second experiment were treated. Again they all became dominant over controls and did not modify their relationships among themselves. Eighty percent of relationships modified by the first or the second treatment remain unchanged without any hormonal support for 4 to 10 months. A first analysis of social interactions does not seem to indicate a higher increase in the frequency of aggressive interactions in treated animals.     

Plasma testosterone and sexual behavior following intracerebral implantation of testosterone propionate in the castrated male rat

Interpretation of behavioral and other effects of intracranial steroid implants depends on knowledge of the rate of release of the implanted hormones into the general circulation. Testosterone propionate implants (200 μg, pellets) in the median eminence and pituitary were found to result in circulating levels of testosterone (T) twice as high as those in the anterior hypothalamus-preoptic area (AHPOA), posterior hypothalamus (PH), and cortex (Ctx). Implants in all cranial areas examined resulted in plasma T levels in the lower range of circulating T found in normal rats for the first 24 hr postoperatively, decreasing thereafter and reaching very low levels by the end of 2 weeks. There were no significant differences in the plasma T levels in rats with implants in the AHPOA, PH, and Ctx, but AHPOA implants were slightly more effective in restoration of sexual behavior than PH implants, and both of these implants were considerably more effective than those in the cortex. There was no apparent correlation between behavioral responses and peripheral levels of T. The major conclusion of this study was that the effects of hypothalamic implants of T on male sexual behavior cannot be explained by the presence of T in the peripheral circulation.