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In captivity, Tupaiu belungeri (Thailand tree-shrew) frequently show aberrant patterns of maternal care which result in the death of offspring. In order to maximize the potential of the tree-shrew as an animal resource for experimental studies we have developed a program for hand-rearing tupaiidae from birth. Newborn tree-shrews were removed from mothers with a history of poor parental care to a nursery maintained under conditions of controlled relative humidity (70 5 10%) and temperature (25 1 O C) on a 12 h dark: 12 h light cycle. The young tree-shrews were fed on a liquid formula until the eyes opened (Day 18-23) and for the subsequent 10 days on a transitional diet until they could feed themselves on solid food. Our hand-rearing protocol appears to conform to the natural weaning pattern of tupaiids. Food consumption during the liquid diet phase was linearly related to age and the increase in body weight in both sexes. The initial growth rate of male and female hand-reared tree-shrews was slower than that of maternally reared animals during the liquid diet phase. The growth rate accelerated subsequently and the body weight of hand-reared tree-shrews eventually reached that of maternally reared animals of the same sex. Various developmental changes occurred during the same period in artificially and naturally reared animals. In both hand-reared and maternally reared groups, the growth rate of male treeshrews exceeded that of females from about Day 40 onward. The accelerated growth rate of male tree-shrews was in apparent association with an increase in androgen secretion at the onset of puberty. The high fecundity of tree-shrews in captivity reinforced with a program for hand-rearing the young make T belungeri a potential alternative to more conventional laboratory species in specific areas of biomedical research.

The reproductive anatomy of the male tree shrew (Tupaia belangeri) was examined and compared with other Tupaiidae. The testes are located prepenially in a pigmented scrotum which is fused to the base of a pendulous penis. The terminal portion of the vas deferens is differentiated into an ampullary gland and joins the duct of the seminal vesicle to form a short ejaculatory duct. The prostate is a compact bilateral body drained by a main collecting duct. In the aggregate, these features indicate that the reproductive system in Tupaia is primate in character. Testicular function in tree shrews is affected by both social and seasonal factors. When males were housed communally, the majority exhibited testicular degeneration accompanied by a loss in the weight and fructose content of the seminal vesicles and in pigmentation of the scrotum. These changes may be due to the presence of dominant conspecifics since animals kept in isolation undergo normal sexual development. Animals captured throughout the year and isolated show seasonal fluctuations in androgenic and spermatogenic function. Reproductive capacity is maximal during the winter and minimal during the summer. Local environmental factors appear to regulate reproductive function so that the greatest number of births occur during the dry season.

The relationship of structure and function in the adrenal gland of the possum Trichosurus vulpecula, has been studied using in-vitro incubation techniques. It was shown that both 17\g=a\-hydroxycorticosteroids and 17-deoxycorticosteroids were produced from radioactive pregnenolone and progesterone, and that these transformations occurred both in the definitive cortex as well as in a special zone of hypertrophied tissue found only in the adult female.In support of earlier findings, it was also shown that the adrenal cortex of the possum has a remarkable capacity to produce C19 steroids (including androstenedione and testosterone) from the radioactive precursors. While most of the transformations occurred with equal efficiency in both types of tissue, the reduction of androstenedione to testosterone seemed to take place more readily in the special hypertrophied zone of the adult female.In studies in vivo, it was found that levels of testosterone in the peripheral blood of the adult female possum were extremely high compared with man. Variations in testosterone levels were not apparently correlated with the stage of the oestrous cycle. The possible pathways by which the adrenal products are synthesized, and their physiological implications are discussed.

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