The pituitary growth hormone cell in space

Growth hormone (GH), produced and secreted from specialized cells in the pituitary gland, controls the metabolism of protein, fat, and carbohydrate. It is also probably involved in the regulation of proper function of bone, muscle and immune systems. The behavior of the GH cell system was studied by flying either isolated pituitary cells or live rats. In the latter case, pituitary GH cells are prepared on return to earth and then either transplanted into hypophysectomized rats or placed into cell culture so that function of GH cells in-vivo vs. in-vitro can be compared. The results from three flights to date (STS-8, 1983; SL-3, 1985; Cosmos 1887, 1987) established that the ability of GH cells to release hormone, on return to earth, is compromised. The mechanism(s) responsible for this attenuation response is unknown. However, the data are sufficiently positive to indicate that the nature of the secretory defect resides directly within the GH cells

Research Notes : A dwarf mutation in \u27Hodgson\u27 soybean

A dwarf mutation was found in a line derived from radiated \u27Hodgson\u27 grown at the Bruner Farm near Ames, IA. The mutant plants were 6 to 10 cm tall, had necrotic leaves, and produced no seeds. twenty-four plants randomly picked from segregating plots were progeny-tested in a greenhouse and in the field

Research notes: Aneuploids and chromosome aberrations from irradiated soybeans

Irradiation treatment of seeds, pollen, or sporocytes has been used successfully to produce aneuploids in a number of genera. When Dr. E. G. Hammond had finished selecting M1 plants from his neutron irradiation experiment, I had the opportunity to go through his radiated material to select off-type and semi-sterile plants and to determine the kinds of aneuploids produced by radiation of soybeans. One- and two-seeded pods from remnant M1 plants were harvested, the M2 plants grown in the field, and the M3 progenies of M2 plants with more than 20% aborted pollen grains were checked for chromosome number and aberrations, using root tip squashes

Animal studies on Spacelab-3

The flight of two squirrel monkeys and 24 rates on Spacelab-3 was the first mission to provide hand-on maintenance on animals in a laboratory environment. With few exceptions, the animals grew and behaved normally, were free of chronic stress, and differed from ground controls only for gravity-dependent parameters. One of the monkeys exhibited symptoms of space sickness similar to those observed in humans, which suggests squirrel monkeys may be good models for studying the space-adaptation syndrome. Among the wide variety of parameters measured in the rats, most notable was the dramatic loss of muscle mass and increased fragility of long bones. Other interesting rat findings were those of suppressed interferon production by spleen cells, defective release of growth hormone by somatotrophs, possible dissociation of circadian pacemakers, changes in hepatic lipid and carbohydrate metabolism, and hypersensitivity of marrow cells to erythopoietin. These results portend a strong role for animals in identifying and elucidating the physiological and anatomical responses of mammals to microgravity

Heterogeneity in the growth hormone pituitary gland system of rats and humans: Implications to microgravity based research

The cell separation techniques of velocity sedimentation, flow cytometry and continuous flow electrophoresis were used to obtain enriched populations of growth hormone (GH) cells. The goal was to isolate a GH cell subpopulation which releases GH molecules which are very high in biological activity, it was important to use a method which was effective in processing large numbers of cells over a short time span. The techniques based on sedimentation are limited by cell density overlaps and streaming. While flow cytometry is useful in the analytical mode for objectively establishing cell purity, the numbers of cells which can be processed in the sort mode are so small as to make this approach ineffective in terms of the long term goals. It was shown that continuous flow electrophoresis systems (CFES) can separate GH cells from other cell types on the basis of differences in surface charge. The bioreactive producers appear to be more electrophoretically mobile than the low producers. Current ground based CFES efforts are hampered by cell clumping in low ionic strength buffers and poor cell recoveries from the CFES device

Experiment K-6-02. Biomedical, biochemical and morphological alterations of muscle and dense, fibrous connective tissues during 14 days of spaceflight

Findings on the connective tissue response to short-term space flight (12 days) are discussed. Specifically, data regarding the biochemical, biomechanical and morphological characteristics of selected connective tissues (humerus, vertebral body, tendon and skeletal muscle) of growing rats is given. Results are given concerning the humerus cortical bone, the vertebral bone, nutritional effects on bone biomechanical properties, and soft tense fiber connective tissue response

Some Factors Influencing the Life Span of Golden Hamsters

The golden hamster has found increased use as a laboratory animal over the last two decades. It is of particular interest because it hibernates although its periods of dormancy are short compared to those of other hibernators (1). The complete spectrum of physiological norms should be determined for this common animal just as they were for the laboratory rat. In the list of normal values for the hamster there is little published information on life span (2). This paper will present records of life spans of 126 hamsters kept under controlled laboratory conditions. Approximately 43% of the colony were maintained with a daily light cycle in a coldroom (6 ± 2 ° C.) for about 4 months each winter. Other conditions of the experiment have been described earlier in detail (1). For the purposes of this analysis the cold-exposed group was treated as a homogenous population, in spite of the fact that some of the animals hibernated. This combining of animals was due to the fact that there was such variation in the total duration of hibernation over the winter periods. Some hamsters hibernated for one day, others were in hibernation for a total of 95 days. The systematic pattern of results justifies this approach to this analysis. To be specific, the data treated in this paper look as if cold-exposure with or without hibernation produced the same effects upon the animals, in most respects. Furthermore, the hibernators were distributed nearly equally among four groups of cold-exposed animals. Later analyses will attempt to consider the influence of hibernation as a separate factor. We will ref.er in this report only to the cold-exposed group: this means a mixed group of males and females of two strains of animals, most of which were coldexposed 4 months, but a few of which received only 3 months of cold-exposure at 6° C. and a few weeks at 16° C. About 12 of the males and 10 of the females hibernated for variable periods of time

New Multiline Oats - Designed to Breeak the Chain of Crown Rust

Until now, oat breeders have been in a race to keep ahead of new strains of crown rust. Now multiline oats show promise of outdistancing the disease. Here\u27s the full story on development and early results with the first multiline oats in the world

Noise power spectral density of the Sundstrand QA-2000 accelerometer

There are no good data on low frequency (less than 0.1 Hz) power spectral density (PSD) for the Q-Flex accelerometer. However, some preliminary stability measurements were made over periods of 12 to 24 hours and demonstrated stability less than 0.5 micro-g over greater than 12 hours. The test data appear to contain significant contributions from temperature variations at that level, so the true sensor contribution may be less than that. If what was seen could be construed as a true random process, it would correspond to about 0.1 micro-g rms over a bandwidth from 10(exp -5) Hz to about 1 Hz. Other studies of low frequency PSD in flexure accelerometers have indicated that material aging effects tend to approximate a first order Markhov process. If we combine such a model with the spectrum obtained at higher frequencies, it suggests the spectrum shown here as a conservative estimate of Q-Flex noise performance

Experiment K-6-22. Growth hormone regulation, synthesis and secretion in microgravity. Part 1: Somatotroph physiology. Part 2: Immunohistochemical analysis of hypothalamic hormones. Part 3: Plasma analysis

The objectives of the 1887 mission were: (1) to determine if the results of the SL-3 pituitary gland experiment (1) were repeatable; and (2) to determine what effect a longer mission would have on the rat pituitary gland growth hormone (GH) system. In the 1887 experiment two issues were considered especially important. First, it was recognized that cells prepared from individual rat pituitary glands should be considered separately so that the data from the 5 glands could be analyzed in a statistically meaningful way. Second, results of the SL-3 flight involving the hollow fiber implant and HPLC GH-variant experiments suggested that the biological activity of the hormone had been negatively affected by flight. The results of the 1887 experiment documented the wisdom of addressing both issues in the protocol. Thus, the reduction in secretory capacity of flight cells during subsequent extended cell culture on Earth was documented statistically, and thereby established the validity of the SL-3 result. The results of both flight experiments thus support the contention that there is a secretory lesion in pituitary GH cells of flight animals. The primary objective of both missions was a clear definition of the effect of spaceflight on the GH cell system. There can no longer be any reasonable doubt that this system is affected in microgravity. One explanation for the reason(s) underlying the better known effects of spaceflight on organisms, viz. changes in bone, muscle and immune systems may very well rest with such changes in bGH. In spite of the fact that rats in the Cosmos 1887 flight were on Earth for two days after flight, the data show that the GH system had still not recovered from the effects of flight. Many questions remain. One of the more important concerns the GRF responsiveness of somatotrophs after flight. This will be tested in an upcoming experiment