Studies of the Metabolic Pattern of Pregnancy in the Rat

Morrison, Seoras Domnhal (1952) Studies of the Metabolic Pattern of Pregnancy in the Rat. PhD thesis, University of Glasgow.

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(1) The relevant literature on the energy, nitrogen and water metabolism during pregnancy is discussed. (2) The methods employed in the present work, to investigate the metabolism during pregnancy in the rat are described in detail, (3) The construction of a respiration calorimeter for the measurement of the total metabolism for continued successive periods of 24 hr. in the rat is described in detail. (4) The operation of this instrument is described in detail. (5) Theoretical considerations in the computation of energy exchanges from the form of data obtained are stated. The interpretation of these exchanges is discussed. (6) The results, with illustrative diagrams, are presented of a total of 173 days' study of the metabolism of the hooded rat. These results cover six pregnancies and sixteen 3- to 5-day periods of reproductive rest, They include data on the components of energy, nitrogen and water exchange, (7) Energy expenditure was found to rise by 10%, food energy intake by 37%, and energy balance was found to be consistently positive during pregnancy. (8) Nitrogen balance was positive in all parts of pregnancy in which it was studied. Some evidence was found for a decline in nitrogen balance to near zero at about the 19th day of gestation, with subsequent recovery to positive levels. (9) Water balance was not significantly different from zero until about the 15th day of gestation. Thereafter there was a consistent water gain by the pregnant organism. No evidence was found of a maternal water gain during pregnancy, and in five out of the six pregnancies there was evidence of dehydration of the maternal tissues. Water intake, vapourised water loss and urinary water loss rose during pregnancy by 56, 4 and 40%, respectively (10) Significant increases in energy expenditure, intake and balance; in respiratory quotient and in vapourised and urinary water losses, with decreases in fluid water intake, water balance and bodyweight increment were found between the first and second pregnancies. It is pointed out, however, that these changes may not be true parity effects, and may be due, in part, to associated change in litter size. (11) Data are presented on the growth of the rat foetus and placenta. The growth of the foetus can be represented by an allometric equation. The growth of the placenta was found to be linear with time, and no evidence was found of any cessation or slowing of growth before the end of gestation. (12) The significance of these results is discussed and an attempt is made to assess their general validity as representative of the pattern of pregnancy in the rat.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Physiology
Date of Award: 1952
Depositing User: Enlighten Team
Unique ID: glathesis:1952-78934
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 28 Feb 2020 12:09
Last Modified: 28 Feb 2020 12:09

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