Mate choice and reproductive success in the red-legged partridge (Alectoris rufa).

Behavioral patterns, reproductive success, and concentrations of plasma-luteinizing hormone, testosterone, and estrogen were compared in pairs of red-legged partridges which had either selected their own mates or had been randomly paired. Males in self-selected pairs called more frequently than males in non-self-selected pairs. Females in self-selected pairs but not those in non-self-selected pairs guarded their nests. Females in self-selected pairs had a greater egg production and laid more of their eggs in nests than females in non-self-selected pairs. There was a significant difference between the two groups in the concentration of plasma testosterone in males, which was higher in males from self-selected pairs prior to the onset of egg laying. These results are consistent with the hypothesis that mate choice affects both reproductive parameters and nest defense in monogamous birds.

Annual testicular activity in the gray partridge (Perdix perdix L.).

Seasonal changes in plasma androgens, testicular total protein content, gonosomatic index, and spermatogenic activity were studied in the grey partridge, Perdix perdix. Moreover, testicular androgen output after stimulation with ovine LH (oLH) was tested in vitro during different periods of the sexual cycle. Androgens and the gonosomatic index peaked in April, during which all the spermatogenic stages were observed. Total protein content in the testes was highest in January and March. Gonadal responsiveness to oLH was found to increase in the period April-May in coincidence with the hormone peak in the plasma, while February testes were irresponsive.

Long-term results in preventive medicine for type II diabetes.

The authors report the results of a 12-year screening for type II diabetes in their Health District (Emilia-Romagna, Northern Italy). The method consisted of two steps, following Pavel and Sdrobici, for early diagnosis of clinical diabetes and IGT. The authors found 1.03% of clinical diabetes and 2.65% of IGT cases in the population examined (200,000 subjects). Statistically significant correlations existed with regard to the various risk factors (familiarity, obesity, fetal macrosomia, occupation). Follow-up after 6 years for IGT subjects showed a 25.5% return to normal of OGTT values, 21.7% improvement, 19% unchanged, 33.8% deterioration. There was a correlation between these results and life-style (diet, reduction in calorie intake, weight loss). Twelve years after these screenings, a 2.7% drop in incidence was observed for type II diabetes in this Health District.

Effect of progesterone on the sexual behavior of the male Japanese quail.

The reduced metabolites of testosterone produced in the central nervous system of birds are known to be involved in the regulation of male sexual behavior. Since progesterone may compete with testosterone for 5 alpha- and 5 beta-reduction, it may also interfere with the sexual behavior of birds. In order to test this hypothesis, progesterone was administered to male quail either transferred from short days to long days or kept in short days and treated with testosterone. Sexual behavior and crowing were scored at intervals for 21 days and the size of the cloacal gland was measured at the same times. On Day 21, the birds were killed and their testes were weighed. The administration of a large dose (1 mg/day) of progesterone depressed the sexual behavior of the birds stimulated either by long days or by the administration of testosterone. It is suggested that progesterone may compete with testosterone for the active sites of 5 alpha- and 5 beta-reductase; alternatively, its effect may be due to an antiandrogenic activity.

Pavel's "dynamic screening" for diabetes type 2: 14 years results in a district of northern Italy.

The AA. report the results of 14 years' screening for diabetes type 2 in their Health District (Emilia Romagna, North Italy), according to Pavel's method, for early diagnosis of clinical diabetes and impaired glucose tolerance (IGT). The AA. found in a first screening 1.03% of clinical diabetes and 2.65% of IGT cases in the population examined (200,000 subjects). Statistically significant correlations existed in relation to the various risk factors (hereditary factors, obesity, fetal macrosomia, job). The follow-up after 6 years for IGT subjects showed a 25.5% return to normal oral glucose tolerance test (OGTT) values, 21.7% improvement, 19% unchanged, 33.8% impairment. There was a correlation between these results and life-style (diet, physical exercise, weight loss). Fourteen years after these screening, a 2.7% negative incidence was observed for diabetes type 2 in this Health District.

Effect of photoperiod and gonadectomy on testosterone metabolism in vitro by the prostate of the golden hamster.

Testosterone metabolism was studied in vitro in the prostate of intact and castrated golden hamsters maintained either in short days (8 h light: 16 h darkness, 8L: 16D) or in long days (14L: 10D). Testosterone was found to be converted into 17 beta-hydroxy-5 alpha-androstan-3-one (5 alpha-DHT), 5 alpha-androstane-3 alpha, 17 beta-diol, 5 alpha-androstane-3, 17-dione and androstenedione. The mean conversion of testosterone to 5 alpha-DHT was higher in prostates from animals maintained in long days than in short days (P less than 0.0025) while that to androstenedione was higher in short days (P less than 0.0005); no significant changes in the formation of the other three metabolites were noted. Castration of animals maintained in short days resulted in a significant (P less than 0.05) decrease in the mean conversion to all four metabolites. In contrast, castration of animals kept in a long-day regime caused a significant (P less than 0.01) decrease in the mean formation of 5 alpha-DHT but a significant (P less than 0.05) increase in the mean formation of 5 alpha-androstane-3 alpha, 17 beta-diol.

[Euglycemizing effect of partial jejuno-ileal resection in rats treated with streptozotocin]. / Effetto euglicemizzante della resezione digiuno-ileale parziale nel ratto trattato con streptozotocina.

Resection of about 50% of the small intestine was performed in rats diabetised with streptozotocin. The first results show that this operation leads to normalisation of sugar metabolism that is partly referable to partial malabsorption, but above all to loss of weight. Current knowledge with regard to the relation between diabetes and obesity is discussed and an account is given of the modern surgical approaches to the treatment of major obesity. Lastly, the suggestion is made that limited digestive bypass may be indicated in cases of insulin-independent diabetes where weight loss and control of blood sugar cannot readily be achieved by conventional medical management.

[Critical analysis of the 2-hour test in mass screenings for the early detection of diabetes]. / Analisi critica del test delle 2 ore in corso di screenings di massa per la diagnosi precoce del diabete.

Out of 500 random trial subjects, taken for a mass-screening for early detection of diabetes mellitus, the Authors tried a correlation between the reliability of the "two-hour test" and the 2 h OGTT. The latter method provides more reliable results, allowing us to diagnose a high percentage of cases which is not possible if the simple two-hour test were used. Research of glycosuria in the course of OGTT did not show any real reliability, whereas it did prove useful in the preliminary phase of our research in order to distinguish the subjects for whom a deeper investigation would be advisable.

Cloacal gland of the Japanese quail: androgen dependence and metabolism of testosterone.

A cloacal gland complex whose growth and development is androgen-dependent exists in the Japanese quail. In-vitro incubation studies of the cloacal gland using 4-14C-labelled testosterone as substrate allowed the positive identification of five metabolites: androstenedione, 5 beta-dihydrotestosterone (5 beta-DHT), 5 beta-androstane-3 alpha, 17 beta-diol, 5 alpha-DHT and 5 alpha -androstane-3 alpha, 17 beta-diol. More polar metabolites, not yet chemically identified, were detected in trace amounts. Androstenedione appeared to be the main testosterone metabolite in immature birds while in mature birds on long daylengths testosterone was preferentially metabolized to 5 alpha-DHT. This change may have been in response to the higher levels of plasma steroids found in mature birds. When various testosterone metabolites, contained in silicone elastomer capsules, were implanted s.c. into castrated birds maintained on a photostimulatory light regime, 5 alpha-DHT, 5 alpha-androstane-3,17-dione, androstenedione and 5 alpha-androstan-3 alpha-ol-17-one were shown to be equipotent with testosterone in stimulating the development of the cloacal gland. 5 alpha-Androstane-3 alpha, 17 beta-diol and 5 alpha-androstan-3 beta-ol-17-one stimulated some growth while 5 beta-DHT, 5 alpha-androstane-3 beta, 17 beta-diol, 5 alpha-androstane-3 alpha, 17 beta-diol, 5 beta-androstane-3,17-dione, androst-5-en-3 beta-ol-17-one and androst-5-ene-3 beta, 17 beta-diol were completely ineffective.