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  • Author: A. B. M. ANDERSON x
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A. B. M. ANDERSON, C. G. PIERREPOINT, T. JONES, K. GRIFFITHS and A. C. TURNBULL

Summary.

The metabolism, in vitro, of isotopically-labelled pregnenolone and progesterone by foetal and adult sheep adrenals has been investigated. Both substrates were almost completely metabolized by the adult tissue, whereas, in the case of the foetus, only pregnenolone showed extensive metabolism. The adult adrenal converted pregnenolone mainly to cortisol, corticosterone and 11-deoxycortisol, whereas corticosterone was the major product from progesterone. The foetal adrenal, on the other hand, yielded mainly progesterone from pregnenolone with only a small conversion to the corticosteroids. The substrate, progesterone, was transformed, in the main, to 11-deoxycorticosterone. No 3β-hydroxysteroid sulphokinase-transferase activity was demonstrated in either tissue. The importance of these findings and the probable pathways involved in the formation of the biosynthetic products are discussed.

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I. M. Rao, W. C. Allsbrook Jr, B. A. Conway, J. E. Martinez, J. R. Beck, C. G. Pantazis, T. M. Mills, E. Anderson and V. B. Mahesh

Summary. Immature rats were treated with diethylstilboestrol (DES) or pregnant mares' serum gonadotropin (PMSG) and forward angle light-scatter (FALS) and 90° light-scatter (90° LS) signals were used to measure the size and the granularity (internal organization) of the granulosa cells, respectively. The results confirmed the presence of two major populations of granulosa cells in the ovaries of both groups of rats, with the same percentage of larger cells in both treatments (52·3% in DES, 49·5% in PMSG). Since DES treatment brings about granulosa cell growth while PMSG treatment causes growth and differentiation, it is evident that there is heterogeneity in granulosa cell sizes during different states of growth and differentiation. There was also heterogeneity in sizes of granulosa cells harvested from follicles of small (< 210 μm), medium (210–420 μm) and large (> 420 μm) diameter. Quadrant analysis of granulosa cells in various fractions collected from Percoll gradients suggested an increase in granularity in the small and large granulosa cell populations. Cell cycle analysis of small and large granulosa cell populations collected from large follicles of rats treated with PMSG indicated that each population was distributed in G0/G1, S and G2/M phases. These results demonstrate that populations of small and large granulosa cells exist in rat ovarian follicles during various stages of growth and differentiation.

Keywords: flow cytometry; granulosa cells; heterogeneity; follicle isolation; DNA analysis; rat

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M Bertolini, A L Moyer, J B Mason, C A Batchelder, K A Hoffert, L R Bertolini, G F Carneiro, S L Cargill, T R Famula, C C Calvert, R D Sainz and G B Anderson

Changes in placental development have been associated with foetal abnormalities after in vitro embryo manipulations. This study was designed to investigate bovine conceptus development and substrate levels in plasma and fluids in in vivo- and in vitro-produced (IVP) concepti and neonates. In vivo-produced and IVP embryos were derived by established embryo production procedures. Pregnant animals from both groups were slaughtered on days 90 or 180 of gestation, or allowed to go to term. Conceptus and neonatal physical traits were recorded; foetal, maternal and neonatal blood, and foetal fluids were collected for the determination of blood and fluid chemistry, and glucose, fructose and lactate concentrations. Placental transcripts for specific glucose transporters were determined by quantitative RT-PCR. No significant differences in uterine and conceptus traits were observed between groups on day 90. On day 180, larger uterine, placental and foetal weights, and an increase in placental gross surface area (SA) in IVP pregnancies were associated with increased glucose and fructose accumulation in foetal plasma and associated fluids, with no differences in the expression of components of the glucose transporter system. Therefore, the enlarged placental SA in IVP pregnancies suggests an increase in substrate uptake and transport capacity. Newborn IVP calves displayed higher birth weights and plasma fructose concentrations soon after birth, findings which appeared to be associated with clinical and metabolic distress. Our results indicated larger concepti and increased placental fructogenic capacity in mid- to late IVP pregnancies, features which appeared to be associated with an enhanced substrate supply, potentially glucose, to the conceptus.